1 Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5- ANNEX 4 Soil Survoy Study FEDERAL DEMOCRATIC REPUBLIC OF ETHIOPIA MINISTRY OF WATER RESOURCES FEASIBILITY STUDY AND DETAIL DESIGN OF BALE GADULA IRRIGATION PROJECT FINAL FEASIBILITY REPORT VOLUME 5- ANNEX 4 SOIL SURVEY STUDY MAY 2010 WWDSE In Association with ICT Final Feasibility Study Report4 5 3 r r r ITFedoral Democratic Republic of Ethiopia- Ministry of Wator Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study List of Volumes in the Final Feasibility Report Vol 1 Executive Summary Vo) 2 Main Report Vol 3 Annex 1 Meteorological and Hydrological Study Vol 4 Annex 2 Geological and Geotechnical Investigations Vol 4 Annex 3 Hydro-geological Study Vol 5 Annex 4 Soil Survey Vol 5 Annex 5 Land Evaluation I Vol 6 Annex 6 Socio Economic Study Vol 6 Annex 7 Settlement Study Vol 7 Annex 8 Irrigation Agronomy Vol 7 Annex 9 Farm Mechanisation Vo) 7 Annex 10 Agricultural Marketing Vol 8 Annex 11 Livestock Study Vol 9 Annex 12 Environmental Impact Assessment Vol 9 Annex 13 Watershed Management Vol 10 Annex 14 Institutional Dev. Vol 11 Annex 15 Financial & Economic Analysis WWDSE In Association with ICT Final Feasibility Study ReportFederal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soli Survey Study List of Volumes in the Final Feasibility Report Vol 1 Executive Summary Vol 2 Main Report Vol 3 Annex 1 Meteorological and Hydrological Study Vol 4 Annex 2 Geological and Geotechnical Investigations Vol 4 Annex 3 Hydro-geological Study Vol 5 Annex 4 Soil Survey Vol 5 Annex 5 Land Evaluation Vol 6 Annex 6 Socio Economic Study Vol 6 Annex 7 Settlement Study Vol 7 Annex 8 Irrigation Agronomy Vol 7 Annex 9 Farm Mechanisation Vol 7 Annex 10 Agricultural Marketing Vol 8 Annex 11 Livestock Study Vol 9 Annex 12 Environmental Impact Assessment Vol 9 Annex 13 Watershed Management Vol 10 Annex 14 Institutional Dev. Vol 11 Annex 15 Financial & Economic Analysis WWDSE In Association with ICT Final Feasibility Study ReportFederal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study TABLE OF CONTENTS LIST OF TABLES. Ill LIST OF FIGURES III ABBREVIATIONS AND ACRONYMS EXCUTIVE SUMMARY.................................................................................................................-,x 1. INTRODUCTION—-1 1.1 Background~...................................................................................................................................................... 1 1.2 Objective-.......................................................................................................................................................— 1 1.3 Scope of the Survey-1 2. DESCRIPTION OF THE PROJECT AREA'.. 2.1. Location and Extent 2.2. Climate 2.3. Geomorphology and Geology 2.4. The land Use and Vegetation Cover 2.5. Hydrology 3.1. Preparation for Field Work~........................................................................................... .............9 3.1.1 Image interpretation field survey planning and Identification of the study area10 3.2. Fielo Investigations10 3.2.1. Site and soil morphological description, and soil sampling..13 3.2.2 Infiltration and Hydraulic Conductivity measurements~14 3.3. Post Fieldwork Stage15 3.3.1 Laboratory Analysis15 3.3.2. Data entry, elaboration and manipulation17 3.3.3. Legend Construction and Thematic Map Preparation18 3.3.4. Presentation of Results19 4. LANDSCAPE CHARACTERISTICS20 4.1 Landform20 4.2 Elevation20 4.3 Topography20 4.3.1 Slope20 4.3.2. Micro-relief.21 4.4 Presence of Surface and Subsurface Rock Fragments21 4.5 Erosion Status21 5. SOIL PHYSICAL CHARACTERISTICS23 5.1 Parent Material23 5.2 Effective Soil Depth23 5.3 Deep boring..23 5.4 Soil Colour24 5.5 Soil Texture24 5.6 Soil Structure25 5.7 Special Structural Features25 5.8 Consistence25 5.9 Surface Cracks„.................................................................................................................................................25 5.10 Bulk Density26 6. SOIL BIOLOGICAL CHARACTERISTICS27 WWDSE In Association with ICT Final Feasibility Study Report JFederal Democratic Republic of Ethiopia- Ministry of Water Resources feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study 6.1 Organic Matter Content............................................................................... ........................................... 6.2 Content of Roots 6.3 Biological Features 7. SOIL HYDROLOGICAL CHARACTERISTICS29 7.1 Drainage29 7.2. Infiltration Rate29 7.3 Hydraulic Conductivity29 7.4 Field Capacity30 7.5 Permanent Wilting Point (PWP)30 7.6 Available Water Capacity31 8. SOIL CHEMICAL CHARACTERISTICS33 8.1 Soil Reaction33 8.2 Electrical Conductivity33 8.3 Calcareousness.................................................................. ......................................................................34 8.4 Mineral Nodules35 8.5 Cation Exchange Capacity35 8.6 Base Saturation35 8.7 Exchangeable Sodium (Na*)36 8.8 Exchangeable potassium (K*)36 2 8.9 Exchangeable Calcium (Ca *)........................................................................:.......................................... 37 2 8.10 Exchangeable Magnesium (Mg *)37 8.11 Cationic Ratios37 8.12.1 Potassium to Magnesium Ratio (K: Mg)37 8.11.2 Calcium to Magnesium Ratio (Ca: Mg)38 8.11.3 Potassium to CEC Ratio (K: CEC)38 8.12 Total Nitrogen38 8.13 Carbon to Nitrogen Ratio (C: N)38 8.14 8.15S0DICITY39 Available Phosphorus39 9. THE SOILS OF THE STUDY AREA-................... 40 9.1. Review of Previous Studies40 9.2 Soil Formation41 9.3 Soil Classification System42 9.3.1 Nitisols43 9.3.2 Luvisols44 9.3.3 Vertisols45 9.3.4 Leptosols48 10. SOIL MAPPING UNITS51 10.1 Legend Formation51 10.2 DESCRIPTION of Soil Mapping Units 10.2.1 Soil Mapping Units V82ccVRhu-peB 10.2.2 Soil Mapping Unit VB2so-ccVRhu-peB99 10.2.7 Soil Mopping Unit VB2moVRca-peB..................................................................................................& 1100..22..83 SSooiill MMaappppiinngg UUnniitt VPBisolccV-ccVRpRecr-st-stACfa................................................................................................... 59 1100..22..94 SSooiill MMoappppiinngg UUnniitt VPBiccVlso-RccVpeCRfhau-pe-stA 1100..22..150SSooililMMaappppininggUUnnititVVBBlccV 2haRNwTnh-ucr-stAB.................................................................................................... fa 1100..22..161SSooililMMaappppininggUUnnititVVBB22hccV aVRRcawn-h-pueCB.................................................................................................. fa 10.2.12 Soil Mapping Unit VBlmoVRca-wnA WWDSE In Association with ICT 77 Final Feasibility Study Report iiFederal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5- ANNEX 4 Soil Survey Study 10.2.13 Soil Mopping Unit VB2hoLVhe-clB........................................................................................................79 10.2.14 Soil Mopping Unit VBlhaLVhe-crB...................................................................................................... 81 10.2.15 Soil Mapping Unit PiccLVhe-crC...........................................................................................................83 10.2.16 Soil Mopping Unit VBlvrLPcaA.............................................................................................. -..............85 10.2.17 Soil Mapping Unit PiccVRhu-peA......................................................................................................... 87 10.2.18 Soil Mopping Units PimoVRca-huC...................................................................................................... 89 10.2.19 Soil Mapping Unit VBlso-ccVRhu-peA........................................................................................ -........ 91 10.2.20 Soil Mapping Unit -R:............................................................................................................................ 93 11. CONCLUSIONS AND RECOMMENDATION........................................................................................ ~.......... 96 11.1 Conclusion..................................................................................................................................-.................. 96 11.2. Recommendation....................................................................................................................................... — 98 11.2.1 Gypsum application..................................................................................................................... .......... 98 11.2.2 Addition of Organic Manures............................................................................................... -.............— 99 11.2.3. Fertility................................................................................................................................................ 100 11.2.4 Soil Erosion Control............................................................................................................................. 101 11.2.5 Leveling and Grading........................................................................................................ .......... ........ 102 11.2.6 Stone Removing................................................................................................................................... 102 REFERENCE............................................................................................................................................................. 103 APPENDIX................ ................................................................... »............................................................ .. ............104 LIST OF TABLES Table 2.1: Monthly mean of climate condition..................................................................................... .. ......... 6 Table 3.1: Soil Field Activities Achievement...................................................................................................is Table 4.1 Slope Class of the Bale-Gadula Command Area....................................................................... 21 Table 5.1: Deep boring........................................................................................................................................... 24 Table 7.1: Summary of Infiltration Rate and Hydraulic Conductivity Measurement...................... 30 Table 7.2: Water Holding Capacity of Bale Gadula.................................................................................... 32 Table 10.1: Legend Description........................................................................................................................... 52 Table 10.2: The Physical and Chemical Characteristics of Soil mapping Units of Bale-Gadula of Command Area........................................................................................................................... 95 LIST OF FIGURES Figure 2.1 : Location and Extent of Bale-Gadula Irrigation Project..........................4 Figure 3.1 : Observation points of the study area......................................................12 Figure 9:1: Soil Unit Map.............................................................................................. 50 Figure 10.1: Soil Mapping Units of Bale-Gadula Irrigation Project..........................94 iiiFederal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5- ANNEX 4 Soil Survey Study LIST OF APPENDIXES Appendix I: Land and Soil Characteristics: Meaning and Classification............ 104 Appendix II:: Field Guideune..................................................................................109 Appendix III: Format for Data Collection........................................................... 119 LIST OF ANNEXES (GIVEN IN SEPARATE VOLUME) Annex 4.1: Data base for Auger Hole Description Annex 4.2: Data Base for Profile Description Annex 4.3(a): Data Base for Libratory Result Annex 4.3 (b and c): Data Base for Infiltration rate measurement and Hydraulic Conductivity WWDSE In Association with ICT Final Feasibility Study ReportFederal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5- ANNEX 4 Soil Survey Study ABBREVIATIONS AND ACRONYMS CaCO3 CEC Calcium Carbonate Cation Exchange Capacity cm Centimetres ECe EVDSA Electncal Conductivity of Saturated Paste Extract Ethiopian Valley Development Studies Authority FAO Food and Agriculture Organization FC Field Capacity G' Gram Ha Hectare ho 22 Hydrogen Peroxide HCI Hydrochloride ITC ISRIC K Km KCI LUT International Institute for Aerospace Survey and Earth Science Potassium Kilometres Potassium Chlonde Land Utilization Type LUP Land Unit Map Mg Magnesium m Meter masl Meters Above Sea Level mm Millimetres M Mole MoWR Ministry of Water Resources Na Sodium NWRC °C PWP PH ToR Natural Water resources Commission Degree Celsius Permanent Wilting Point Soil Reaction (log H*ions, acidity, basicity) 10 Term of Reference WWDSE In Association with ICT Final Feasibility Study ReportFedoral Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study UNESCO - United Nations Educational Scientific and Cultural Organization UTM Universal Transverse Mercator WWDSE In Association with ICT Final Feasibility Study Roport viFederal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Projoct VOL 5- ANNEX 4 Soil Survey Study EXCUTIVE SUMMARY Feasibility level soil study had been carried out in Bale-Gadula Irrigation Project covering 7721 ha of land The main objective of the investigation was to provide detail information on the land and/or soils of the study area, which may form a basis for confirming/rejecting the irrigation potential, crop selection, irrigation design and agricultural input requirements such as fertilizer application. The Bale-Gadula irrigation project area is found in the south-eastern part of the country and it stretches over some part of Goro, Sinana and Ginir weredas in Bale administrative zone of Oromiya Regional State. The project area is categorized in to traditional kola agro climatic zone with bio- modal rainfall system. The mean rainfall is estimated to be 998.7 mm/year .The average minimum temperature is 15.60C and the maximum temperature is 29.1 OC. The average monthly relative humidity is 69.42 % the maximum is in November month 74.11%. The minimum value of RH is 57.64% in March. The land cover of the project area is intensively cultivated land. The major land use is agro-pastoralism. The head of Weyib River originates from high volcanic mountain of Mount Bale and finally drains to Genale-dawa River Basin. The project area is reachable by an asphalt road and graveled after traveling some 500 km from Addis Ababa via Shashemene to Bale-Robe and Goro towns. The present investigation adopted rigid grid survey techniques. The auger soil description has been made every 250 x 400m along transect to a depth of 1.20m. One auger observation represents for 10 ha area and the achieved observations include a total number of 779 auger observations and 75 profile pits observations, and 182 soil samples were collected from 48 profile pits and analyzed in WWDSE soil laboratory for standard analysis. Infiltration rate and hydraulic conductivity were measured in situ at 8 representative sites each in triplicates. To check the depth of the impervious horizon and to monitor the fluctuation of the water table 8 deep borings were made by auger boring from the bottom of the profile pits below 2m depth down to a depth of 3-5m on model profile sites. WWDSE In Association with ICT Final Feasibility Study Report ixFederal Democratic Republic of Ethiopia- Ministry of Water Resources feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soli Survey Study Soils of the project area are developed on colluvail and alluvial process. The soil classification of the study area has been made based on the World Reference Base for Soil (FAO, 2006) As a result of the investigation five major soil units namely: Vertisols, Cambisols, Luvisols, Nitisols and Leptosols. The most extensive soil unit is Vertisols. The soils of project area have been grouped into 18 soil mapping units based land form, phases such as stoniness, erosion and shallow soil depth and soil units and in addition to that there have been identified 1 miscellaneous land unit. Soil nutrient status of the project site is generally moderate to high. The content of organic carbon of the area is high, ranging from 0.21 3 91% with an average of 1.18%; the soils have very high CEC & BSP and their soil reaction slightly acidic to extreme alkaline. The CEC value of the project soil types is very high, ranging from 3.2 to 118.33 with am average value 56.2 meq/100g soils. The content of phosphorus is very low to low and the average value is 2.99 ppm Supplementary phosphate will be required. The total nitrogen content of the soil is medium to high. Nitrogen value is between 0.02 and 0.39%; where as the average value is 0.1%. Supplementary nitrogen fertilizer would be required. Generally, the content of exchangeable Ca is high, which ranges from 3.62 to 86.46, with average of 30.07 meq/100 grams of soil Exchangeable Mg is high, varying from 1.34 to 40.77 with an average value 9.16 meq/100 gram of soil. The reserve of K is low to high (0.64 to 5.63 meq/100g soil with an average value of 0.648 meq/100g soil). The EC value of all mapping units is low and thus salinity will not be any problem. The soil is in some cases calcareous and sodic. The major constraints of the area are soil sodicity in some areas, soil erosion, dense vegetation cover and surface stoniness. To alleviate the above mentioned and others related problems should be taken the following mitigation measures. 1) The Organic Carbon and Nitrogen content levels in top soil are medium to high, indicating definite necessitates for liberal N-fertilization for realizing potential high yields of crops. Besides that to maintain fertility status at optimum level it is vital to apply organic and inorganic fertilizers concurrently. WWDSE In Association with ICT Final Feasibility Study Report XFederal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study 2) Ploughing back of crops residues and mulching should be encouraged to raise very maintaining carbon levels and to improve top soils structure of the soils and competing soil loss. Legumes may also help in getting better topsoil structure, adding nitrogen to soil by fixation from atmosphere and there by improving the structure of top soils. 3) Available phosphorous and exchangeable potassium for most of the soils within the study area have been found to be at low. Thus application of chemical fertilizers of phosphorus and potassium are essential. 4) The soil reaction of the soils of the command area is moderately to strongly alkaline and thus it requires immediate amelioration measure, such as applying of gypsum to the soil. 5) The electrical conductivity values of the soils of the command area are low so there may not be any immediate fear of soil-salinity development. 6) Erosion hazard should be controlled by appropriate anti-erosive control mitigation measure. 7) Considerable part of the project area is covered by common to many stones and thus required removal of stones. 8) Most of the command area is in need of leveling/grading. WWDSE In Association with ICT Final Feasibility Study Report xiul..Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Balo Gadula Irrigation Project VOL 5- ANNEX 4 Soil Survey Study 1. INTRODUCTION 1.1 BACKGROUND The WWDSE has entered to an agreement with MoWR to provide consultant services for Bale-Gadula Feasibility Irrigation Project. One of among the study component is the investigation of soil survey and land evaluation, which assist the design of Irrigated agricultural development of the area. The feasibility irrigation project is planned to be conducted in Goro woreda, Bale zone, Oromia Regional State following the course of Weyib River, which stretches from west to east in the zone. The Weyib River sub-basin is found in Genele-Dawa River Basin. The Weyib, having its source in Bale Mountain, drains into Genale River. The soils of the study area have been investigated during pre-feasibility level soil studies of the Bale-Gadula Valley (EVDSA, 1990). The soil survey of the Bale-Gadula irrigation project is covered an area of about 7721 ha in Bale-Gadula valley, however in the TOR stated that the project area is 5,000 ha. 1.2 OBJECTIVE The main objective of the present soil survey is to provide detail information on land and soils of the command area of the project as basis for confirming /rejecting the irrigation potential (all or part of the area), crop selection, irrigation design, agricultural input requirements such as fertilizer applications etc. The study also focuses on identifying the various topographic forms, soil types, present land use assessment and evaluating the existing land use pattern and serve as a basis for assessment of land and crop suitability for irrigation. 1.3 SCOPE OF THE SURVEY The soil survey and land suitability will be carried out using internationally accepted standards, methods and procedures. It will be designed to confirm the standards and requirements for the feasibility level study to be earned out. Therefore, even though it has not been mentioned in the TOR, the study shall address tasks and salient components that the consultant deems requisite to be WWDSE In Association with ICT Final Feasibility Study Report 1IFederal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Dotall Design of Balo Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study integrated. The scope of the work to be undertaken to achieve the objectives of the study will include, but not limited to: • Investigate, identify, analyze and descnbe the distribution of different soil and terrain units. • Prepare soil and land suitability map at scales of 1:10,000 respectively and, observation map for project site at appropriate scales. • Survey to an average density of one per 10 ha over an area of about 7721 ha, which is equivalent to 779 observations has been carried out. About 10% of the auger holes were profile pits (75) and 10% of profile pits were selected for physical test and core ring sampling (8). • Conduct standard soil physical and chemical analysis. • Carry out deep boring to depths of 3 to 5 m for all 10% profile pits. In order to check the fluctuation of water table and salinity test. • Determination of the permeability of the soils to establish the drainage class, in triplicate at representative sites as the soil conditions permit, • Measurement of infiltration tests using double ring infiltrometer, in triplicate at .representative sites as soil condition permit • Collect undisturbed core samples for.determination of moisture release characteristics at representative sites (infiltration, permeability tests and core samples were carried out at the representative sites). • Auger observations to a depth of about 1.20 m and 2m (pit) or lithic contact, wherever was shallower ? ■■■■-_ ■— WWDSE In Association with ICT Final Fallibility Study Riport 2Fed oral Domocratlc Republic of Ethiopia- Ministry of Wator Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Projoct VOL 5-ANNEX 4 Soli Survoy Study 2. DESCRIPTION OF THE PROJECT AREA 2.1. LOCATION AND EXTENT The Bale-Gadula irrigation project area is found in the south-eastern part of the country, itself located about 500 km south-east of Addis Ababa and it stretches over some part of Goro, Sinana and Ginir weredas in n Bale administrative zone of Oromiya Regional State and it occupies an area of 7721 ha. The study area is located in UTM zone 37 and lies between the following coordinates: South-North: 778016-793118 East-West 647584 UTM E - 677784 E ha WWDSE In Association with ICT Final Feasibility Study Report 3rM- 600000 1 650000 700000 \garfa Ag a rf a Diversion weir insho ^OCL.- . °Q FEDERAL DEMOCRATIC REPUBUC OF ETHIOPIA MINISTRY OF WATER RESOURCES Bale Gadula Irrigation Project Area WELMEL, YADOT AND BALE GADULAJRRIGATION PROJECTS erbere BALE GADULA IRRIGATION PROJECT CONSULTANT . WATER WORKS DESIGN AND SUPERVISION ENTERPRISE I SUB INTERCONTINENTAL CONSULTANTS AND CONSULTANT TECHNOCRATS PVT. LTD Location map the Project AreaFederal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5- ANNEX 4 Soil Survey Study 2.2. CLIMATE The study area categorized in to " Woina-Dega" traditional agro climatic zone. The average annual rainfall is 895.5 mm. The rainfall in the Bale-Gadla project area is characterized by bio-modal type. The monthly rainfall varies from 51.66 mm in November to 91.2 mm in May. The monthly average rainfall is estimated to be 74.63 mm. The dry seasons ranges from November to January and May to July. The average minimum temperature is 7.99°C and the maximum temperature is 21.44 °C. The mean monthly temperature is 14.72°c. The monthly wind speed ranges from 1.44 m/second to 3.97 m/second. The monthly sunshine varies from 5.8 hrs/day (July) to 8.54 hrs/day (December). The average monthly relative humidity is 77.21 %; the maximum is in June month 84%. The minimum value of RH is 63.37% in February. WWDSE In Association with ICT Final Feasibility Study ReportFederal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project Table 2.1 : Monthly mean of climate condition VOL 5-ANNEX 4 Soil Survey Study Monthly mean of climate condition of Sinnana station | Parameter (type Months Jan. Feb. Mar. Apri. May June July Aug. Sept. Octo. Nov. Dec. Total Ave. Maximum | tempratu r(oC) 21.65 21.64 21.52 20.71 20.82 21.08 21.69 21.77 21.98 21.39 21.56 21.50 257.30 21.44 Minimum temperature (oC) 7.65 7.93 8.66 9.07 9.04 .9.03 8.24 7.60 6.90 6.84 7.48 7.43 95.88 7.99 Relative humidity 64.64 63.37 68.96 81.23 81.57 84.00 81.24 81.02 83.19 83.50 79.00 74.78 926.50 77.21 Wind speed (m/sec) 1.76 2.08 2.38 2.23 2.41 3.40 3.97 3.71 2.74 1.72 1.44 1.57 29.40 2.45 Sunshine hours (hr) 8.01 8.54 8.12 5.98 6.82 7.69 7.09 6.82 5.80 6.03 7.72 8.09 86.72 7.23 | Rainfall (mm) 71.23 87.93 89.20 79.64 91.20 89.70 82.70 54.22 72.67 71.40 51.66 53.99 895.53 74.63 Source: Metrological and Hydrological Study Report WWDSE In Association with ICT Final Feasibility Study RoportFederal Democratic Ropubllc of Ethiopia- Ministry of Water Resources ■Feasjblllty Study and^Detail Design of Bale Gadula Irrigation Project 2.3. GEOMORPHOLOGY AND GEOLOGY VOL 5- ANNEX 4 Soil Survey Study The plateau and foothills, as well as the valley bottom and terrace are underlain by olivine basalt and tuffs of the lower Tertiary Trap series. The area has four geomorphic units. They are Plateau with undulating summit, the undulating older valley bottom, nearly level river terrace and alluvial valley. 2.4. THE LAND USE AND VEGETATION COVER The land covers of the study area include manly intensively cultivated land, residential area and grazing land. The land use of the area is principally intensively rainfed peasant cultivation of cereals, spices and pulses. The major food crops grown in the project area are cereals, pulses, spices and oil seeds. The major cereal crops are maize, wheat, barley, teff and oats. The man pulse crops are haricot bean, pea, chick pea and pea. Spices that are grown in the area are coriander, black cumin and fenugreek. The main oil crop is flax. Most of the people are mainly engaged in subsistence farming system. The family is the major source of farm labor. Children also contribute labor, particularly to livestock tending. There is division of labor by sex and age. Women and children contribute to weeding, harvesting, threshing and transporting grain. Livestock husbandry activities (feeding, milking, herding, barn-cleaning, dung cake-making and forage collection) are shared among the household members. The responsibility of women includes milking cow (at times assisted by men), barn cleaning and dung cake-making. Men are involved in forage collection and feeding livestock. Herding of livestock is mostly the responsibility of children. Ploughing is done by men and in general farming is their responsibility. Cattle are the most important livestock species in the project area. Their principal contributions include draught power for cultivation, threshing and to provide manure. Goats are economically important in the area. Farmers keep goats for various reasons. They are a significant source of investment, security end cash. They are easily sold off at times of economic difficulties. WWDSE In Association with ICT Final Feasibility Study Report 7Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Balo Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study Crop and livestock subsystems are highly integrated. Crop residues provide a major share of the livestock feed while milk, meat, hides, manure and income are major livestock outputs. Livestock also serve as stored wealth in the form of physical animal number, and therefore serve as an asset and security. Land preparation is accomplished by using local plough drawn by a pair of bullocks or oxen. The plough is made of wood and is fitted with a pointed iron bar. It is locally called "maresha”. The number of plowing depends on the intensity of weed infestation, crops and its seed size. 2.5. HYDROLOGY The main river is in the study area is Weyib River. The Weyib River, having its sources in Bale Mountain, flows from north-west to east by bordering the command area from south. There are other intermittent rivers such as Asendabo. These small rivers collect runoff from their catchment and discharging into the main river Weyib River and at the end the Weyib River drains in to the Genale- Dawa River Basin. WWDSE In Association with ICT Final Feasibility Study Roport 8Foderal Democratic Republic of Ethiopia- Ministry of Wator Resources feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5- ANNEX 4 Soli Survey Study 3. METHODOLOGY The whole study process for best use of the assignment was sub-divided in to three phases, namely preparation for fieldwork, fieldwork and post field work. Accordingly, the materials and methods will be discussed in detail as follows: 3.1. PREPARATION FOR FIELD WORK Both the soil scientists and soil survey team carried out different preparatory tasks to begin the field soil survey. The pre fieldwork was scheduled in such way that the teams have adequate time to gather all relevant information, working materials and logistics before departure to the project area. The accomplished pre field works were concerted on review of previous studies, identification of data gap, identification of the study area and planning of the field survey. At this stage construction of preliminary legend, satellite imagery, which ever is available have bee made. However, interpretation of aerial photographs at this stage was not available. Location, probable numbers and depth of pits, augers, deep borings etc has been given. Updated work plan and preliminary soil mapping unit has been prepared for the subsequent ground field surveys and the soil survey investigation crew mobilized to the area. Having data and information from secondary source, the field survey was planned in line with TOR and technical proposal. On the other hand field survey checklists and field data collection formats for soil profile description, soil auger description, in-situ infiltration and hydrologic conductivity test recording sheet were prepared. Out of the existing soil survey crew, soil survey experts and technicians were assigned to execute the survey. All necessary field equipment, material, vehicle and other logistics were arranged and fulfilled Since, the survey teams are experienced in soil survey discussion on how to proceed and familiarizations of the proposed survey methodology were made before of the team departure to the survey. Interpretative soil base map was prepared using previous studies maps and Global map imagery. The survey was planned by combining both grid survey approaches. Auger hole observation follow pre-determined grid which was located on the base map at WWDSE In Association with ICT Final Feasibility Study Ro port 9Federal Democratic Republic of Ethiopia- Ministry of Wator Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study 400m apart transects and auger observation sites were placed at every 250m intervals (400 m X250 m). While, profile pits pre located at every 1km intervals (1km X1km). The profile pits and auger hole observations were planned to ensure a minimum density of one observation per 10 ha. 3.1.1 Image interpretation field survey planning and Identification of the study area Boundaries of major land characteristics were drawn based on observable features of aerial photographs and satellite imageries. The base map was prepared at scale of 1:25,000 on 10m contours interval, which was used as a base for the field planning. The remaining land units, which were considered as less suitable for irrigation within the command area, were surveyed at lesser intensity. That is one observation per 30 ha at representative sites at less potential land. The auger survey teams were free to locate the specific auger observation in less potential area at the above-mentioned intensity within the given area. The details of the observation made during this study, both profile pits and auger observation are given as separate map 3.2. FIELD INVESTIGATIONS Ground investigation constitutes the main stage of field data gathering, upon which the soil survey report, soil map preparation and hence the land suitability evaluation and development possibilities have been based. The soil survey team mobilized to the Bale-Gadula area in June 21, 2009. The team for two days made camping, reconnaissance site visit and discussion with local administrative bodies and then the actual work started on June 24, 2009 and completed July 25, 2009. Bale-Gadula project soil survey team were composed of four auger crew, one infiltration and hydraulic conductivity measurement group, and two team leaders or profile pit. The team leaders were responsible for entire field level planning, leading the field survey and profile pit description. The field coordinator was responsible for overall technical advice, overall coordination of the crew, management and facilitation of logistics. Most of the survey team members have direct or related academic qualification and sufficient experience in soil survey. WWDSE In Association with ICT Final Feasibility Study Roport 10Federal Democratic Republic of Ethiopia- Ministry of Water Resources feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study Hence, duties and responsibilities of the survey crew were given as per individual educational background and experience. In the present study rigid grid survey technique was applied with an average observation density of one per ten ha. However, the observation density has varied between one per 4 ha and one per 30 per ha deepening on the homogeneity and heterogeneity of the area. The group has made a total of 779 auger hole observation, dug 75 profile pits, and 8 infiltrations and hydraulic conductivities measurement and collected 182 soil samples from 48 profile pits in Bale-Gadula. WWDSE In Association with ICT Final Feasibility Study Report 11648000 656000 664000 672000 l' 20 Diversion wier A B*P-04A *G^0€A I A Ala A AAA a▲aa ▲ A . *00107* * * AAAA AAAAAA AAAAAAAAA AAAAAAAAAA aaaaaaa AAAAAAAAA BAP42 * AAAA AAAAA AA Bale Gadula Irrigation Project Area FEDERAL DEMOCRATIC REPUBLIC OF ETHIOPIA MINISTRY OF WATER RESOURCES WE LN EL, YADOT AND BALE GADULA IRRIGATION PROJECTS PROJECT bale GADULA IRRIGATION PROJECT CONSULTANT WATERWORKS DtSTGN ANO SUFtRVIMGN ENTERPRISE sue CONSULTANT • INTCTCONTA ..’.ANTS a?© •_ <rg TECHNOCRATS PVT LTD MAPTITL1 Soil Observation Points DATE 648000 ----- 1---- 656000 ----- 664000 “i SCALE Flfl. No. May, 2010 1:80.000 3.1 672000 782000 788000 794000Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5- ANNEX 4 Soil Survey Study 3.2.1. Site and soil morphological description, and soil sampling The density of auger hole and profile pit observations is discussed in this section. The auger and profile pits site were physically located on the field by the help of GPS using pre-determined coordinates on the base map. The site condition of every auger and profile pits were carefully filled on the first pages of the description sheets. In all observation sites, the most possible land characteristics as well as other pertinent information like UTM coordinate and elevation (using GPS and Altimeter), topography, land form, land element, slope percentage (with the help of Clinometers), micro topography, land use and vegetation, parent material, presence of rock outcrops and stoniness, surface sealing and cracks, erosion condition, surface drainage, flooding, etc were recorded. Beside, filling the site condition physical features was sketched on the description sheets to aid final mapping. Auger hole drilling was carried out up to a depth of 1.2 m unless restricted by lithic contact. Soil morphological characteristics less affected by simmering effect of auger such as thickness of each horizons, soil color (with help of Munsel Color Charts); presence and characteristics of mottles, field texture, rock fragments, cementation/compaction, mineral nodules, and presence of CaC03 (using 10% HCI) were described and recorded on the formats. Accordingly a total of 779 auger hole observations were made to satisfy observation density of one per 10 ha in potential area and one per 30 ha in less potential area. Profile pits were opened up to depth of 2m at representative sites if not prohibited by lithic contact. Location of profile pits was made after review of auger holes observation of each land unit. The density of profile pits stated on the TOR was corrected to 10% of the total observation out of which 60% of opened profile pits were sampled. Hence a total of 75 profile pits were opened, and site conditions as well as morphological characteristics were described. Out of the total opened profile pits, 48 profile pits were sampled for routine soil physical and chemical laboratory analysis, which was carried out at WWDSE and NSRC laboratory. All morphological characteristics indicated on Guideline for Soil Description (FAO, 2006) were described for all profile pits. A total of 182 soil samples were collected from each WWDSE In Association with ICT Final Feasibility Study Report In oFederal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Balo Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study natural horizon of sampled profile pits for routine physical and chemical laboratory analysis. Deep auguring and core sampling were made for 8 profiles. Samples of deep augers were taken at every one-meter depth interval up to depth of 3 meter from the bottom of profile pits and core samples were taken at every natural horizon up to 2m depths unless limited by lithic contact from model profiles (Table3.1) 3.2.2 Infiltration and Hydraulic Conductivity measurements Double Ring Infiltrometer and Inverted Auger Hole method respectively in triplicate at 8 representative sites measured infiltration and permeability of soils of different land unit's in-situ. All possible cares which affect infiltration such as careful removal of vegetations, insertion of both rings to required depth (15 cm), maintaining the water level of the outer ring to the level of inner ring, avoiding turbidity while putting water, etc were well taken during the test. All field level physical tests and sampling (infiltration and permeability measurement, core ring sampling, deep auguring and sampling) were done in and around model sampled profiles of the potential area. It has been carried out measuring of tree trunk diameter and counting of the number of trees of various diameter classes on representative sites on area of 50 meter x 200 meter for estimation of clearance of vegetation cost. Stone counting were made on representative sites of about 10 m x10 m for the purpose of estimation stone picking. In order to accomplish the given task on time and analysis other input activities of the final outputs (final report and annexes) such as data entry, mapping, soil samples laboratory analysis were carried out parallel to the fieldwork. However, generally the activities classified as post field works includes data entry, data elaboration & manipulation, laboratory analysis, legend construction and mapping, data interpretation, final map production, report writing, etc. WWDSE In Association with ICT Final Feasibility Study Report 14Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project Table 3.1: Soil Field Activities Achievement VOL 5- ANNEX 4 Soil Survey Study Sr No Activities Unit Number of Observation Number of I samples 1 Sampled Profile Pits No 48 182 2 Non Sampled Profile Pits No 27 3 Auger Boring No 779 4 Deep Boring No 8 5 Infiltration Rate No 8 6 Hydraulic Conductivity No 8 I - 3.3. POST FIELDWORK STAGE Prior and during this stage a systematic re-interpretation of aerial photographs and/or imagery, field and laboratory data entry, analysis and interpretation of the results, final legend construction, thematic map preparation and report writing were be made. 3.3.1 Laboratory Analysis Soil samples collected from natural horizons (ranging from 3-5 samples) of representative profile pits were analyzed for usual physical and chemical characteristics. Bulk density and moisture characteristics were determined from core ring samples while deep auger samples were tested for salinity. This has been served for the purpose of soil classification and assessment of fertility level. The soil samples analyses were carried out at the Water Works Design & Supervision Enterprise and National Soil Research Centre (NSRC) Soil Laboratories. All analyses except for bulk density determination were made on air dried and crushed to pass through a 2-mm sieve size according to the procedures outlined by Van Reeuwijk (1993). The important physical and chemical parameters determined in the laboratories, based on standard methods as follows: • Soil pH measured in H O and 1 M KCI at a soil/solution ratio of 1:2.5. 2 • Organic carbon (OC) determined by the wet combustion procedure of Walkley and Black method. WWDSE In Association with ICT Final Feasibility Study Report 15Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5- ANNEX 4 Soil Survey Study • The available phosphorus content of the soils has been determined by 0.5 M sodium bicarbonate extraction solution (pH 8.5) method of Olsen. • Electrical conductivity (EC) was determined at a soil/water ratio of 1:2.5 • The cation exchange capacity (CEC) were be determined by saturation with NH OAc (ammonium acetate) at pH 7 and subsequent replacement of 4 NHZ by NaCI extraction. • Particle size distribution was determined by hydrometer method following pre-treatment with H O to remove organic matter and dispersion aided by 22 sodium hexametaphosphate. • Exchangeable Ca & Mg measured by following ammonium acetate leachete using Atomic Absorption Spectrophotometer (AAS), • Exchangeable Na & K has been measured by Flame Photometer. • The free CaCO content of the soils was determined by acid neutralization 3 method. • Total nitrogen was determined by the Kjeldah method. • Moisture volume at field capacity (1/3 atm) and at permanent wilting point (15 atm) by pressure plate extraction Calculated Parameters The following values of parameters are calculated from the available data as follows: ■ Soil organic matter (SOM): Assuming that organic matter forms 58% of organic carbon, SOM values are obtained by multiplying values of soil organic carbon by 1.724. The values are expressed in percentages of SOM contents. ■ Percentage base saturation (PBS): This is a measure of the degree of saturation of the soil with bases. It is obtained by dividing the sum of bases (Ca, Mg, K and Na) by CEC values. It is expressed in percentages. ■ Cation - ratio This is a measure of saturation of the soil with a specific cation. • Exchangeable sodium percentage, ESP (deduced from CEC and exchangeable Na). WWDSE In Association with ICT Final Feasibility Study Report 16Federal Democratic Republic of Ethiopia- Ministry of Water Resources VOL 5- ANNEX 4 ^Feas ibility Study and Detail D oslgn of Bale Gadula Irrigation Project Soil Survey Stu dy * Available water ho lding capacity (AWC) : This is a m easure of easily ava ilable (soil) water to be absorbed by plant ro ots. Findin g differen ces between field capacity (FC) and permanent wilting point (PWP) obtain it. The result is then expressed in percentages. • Carbon/nitrogen ratio (C: N): This measures the degree of mineralization of total nitrogen in relation to soil organic carbon level. It is obtained by dividing the value of percent organic carbon by value of percent total nitrogen. 3.3.2. Data entry, elaboration and manipulation All data to be collected during the fieldwork and laboratory results have been entered into a database. Parallel to the field data collection: laboratory analysis, entry of both field and laboratory data in computer; systematic reinterpretation of aerial photographs and satellite imagery were made. The field survey and laboratory analysis data encoding into Microsoft Access and Microsoft Excel for appendix attachment production, electronic storage and GIS data processing were made simultaneously. Three data encoders under supervision of the consultant made the data encoding. The consultant checked all the row and encoded data and edited errs made while data encoding. The soil data bases encoded were site description, morphological description of both profile pits and auger holes, laboratory analysis results, results of infiltration and hydraulic conductivity measurement. The data entered in MS Excel have been transformed in database IV format for use in Arc GIS. The soil database and GIS used to generate statistical and cartographic information. At the same time acquisition of other important maps and data prepared by other disciplines and stored in GIS of the project were made Aerial photographs and 1:50,000 scale topographic maps; of the study area were collected from Ethiopian Mapping Authority (EMA) and interpreted. The preliminary interpretative base map was used together with the primary image sources like 1:50,000 scale aerial photographs, and satellite imagery, field survey data to reinterpret the mapping units and prepare appropriate indicative legend. Land units boundaries were drown on the bases of observable tone and characteristics of aerial photographs, and satellite imagery and assisted by field level sketches on base map. Detail analyses were made using field and laboratory data to construct the legend. The interpreted soil WWDSE In Association with ICT Final Feasibility Study Report 17Fcdoral Democratic Republic of Ethiopia- Ministry of Water Resources Feas I bility Study and Detail Design of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study boundaries were transferred from the aerial photographs to the base map and digitized for production of soil maps. Observation points were located on location map and used for characterization of each mapping units and inclusions. The observations were categorized and grouped together as per site conditions, morphological & physic-chemical characteristics of each soil mapping units. 3.3.3. Legend Construction and Thematic Map Preparation Initially the command area was mapped by the help of GIS based on the slope condition to identify the potential and less potential area within the pre-determined boundary. A 1:50,000 scale aerial photograph purchased from Ethiopian Mapping authority were located on topographic map prepared by the project GIS. To ease the aerial photograph interpretation topographic map having photo index and different land features such as streams, road and etc were re-digitized and produced base map. The aerial photographs were interpreted using table stereoscope. The properties used to draw boundaries on aerial photographs and satellite imageries are land and soil characteristics. Characteristics that have direct relation with soil formation used in delineation of boundaries on aerial photograph include soil gray tone difference, slope, vegetation, drainage pattern, etc The soil boundaries were transferred from aerial photographs to the digitized base map and produced interpretative soil map. Primary legend was constructed for interpretative soil map based on major land characteristics such as slope, soil gray tone difference, vegetation cover and drainage pattern. As discussed in above, observation pointes (auger, profile pit & profile pits with field physical tests etc) were located on base map to assist the re-interpretation of images in combination with field and laboratory data. The delineated mapping units as per interpretation are characterized using field and laboratory data. Following detail analysis of field and laboratory data and characterization of each mapping unit legend was again rectified and finalized. Parallel to soil map production all observation points located by GPS readings were entered in to database and is connected to GIS to produce location map. The soil map and the I — — WWDSE in Association with ICT Final Feasibility Study Report 18Federal Democratic Republic of Ethiopia- Ministry of Wator Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study observation location map were used together by overlaying one on the other. The 1: 1 0,000 soil-terrain map with final self-contained legend has been prepared. 3.3.4. Presentation of Results The following standard soil report and thematic maps (with complete self- contained legend) at appropriate scales has been presented, but not limited to: • Project location map • Location map of soil profile pits, auger holes, deep borings, infiltration and hydraulic conductivity test sites • Soil at 1:10,000 scale • Soil Mapping Unit maps at 1:10,000 scale • Standard soil survey report, with all necessary tables, appendices and annexes accompanying the report. WWDSE In Association with ICT Final Feasibility Study Report 19Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Dotall Design of Balo Gadula Irrigation Project VOL 5- ANNEX 4 Soil Survey Study 4. LANDSCAPE CHARACTERISTICS 4.1 LANDFORM Upper plain base on slope is regrouped into three classes i.e. nearly to level land with slope gradient 0-1%, very gently land with in slope range 1-2% and undulating sloppy land wit with slope gradient 2-4%. 4.2 ELEVATION The height of a point on the earth's surface, relative to mean sea level (MSL). Elevations of the site above mean sea level is generally measured by means of an altimeter, calibrated with reference to a point of known elevation, and are expressed in meters. The project site is situated with in elevation range of 1527 and 2096 masl. The elevation is gradually decreased from west to east of the command area. 4.3 TOPOGRAPHY The topography or surface configuration of the area is the most important landform characteristic considered in estimating the land development costs and the suitability of land for certain purposes. It is studied with respect to its two important aspects i.e. slope and micro-relief, as discussed below. The level to gently slopping topography of the area is favorable for mechanization and irrigation. Some areas of gentle slopes (3-4%) may require land leveling work. 4.3.1 Slope Slope refers to the inclination of land surface from the horizontal, which is generally measured with the help of clinometers and expressed in terms percentage or in descriptive terms (0-1%: flat. 1-2 almost flat, 2-4% gently sloppy , sloping 4-6% and strongly sloping 6-15% ). In the case of present work the slope class is categorized in five class 0-1%, 1-2%, 2-5%, 5-8% and >8%. The studied area is predominated by 0-1% slope class, covering about 55%, then 1-2% class WWDSE In Association with ICT Final Feasibility Study Roport 20Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Doslgn of Bale Gadula Irrigation Project VOL 5- ANNEX 4 Soil Survey Study occupying some 23%. Thus the area is suitable for mechanization and irrigation development. Table 4.1: Slope Class of the Bale-Gadula Command Area Sr No Slope Class in % Description Area Ha % 1 0-1 Flat 3854 50 2 1-2 Almost flat 1943 25 3 2-4 Very Gently Sloping 684 9 4 4-6 Gently Sloping 281 3.6 5 6-8 Sloping 177 2.3 6 >8 Strongly Sloping 782 10.1 Total 7721 100 4.3.2. Micro-relief Micro-relief applies to minor undulations and irregularities of the land surface or, in other words, minor differences of height between the crests and the troughs, which commonly imply differences in soils. The major micro-reliefs of the area are gilgai and termite mound. Termite mounds occurred in well drained soils, including Luvisols. While gilgai occurs on Vertisols. 4.4 PRESENCE OF SURFACE AND SUBSURFACE ROCK FRAGMENTS The major soils of the project area are free of stones and stoniness and there will be no limitation for irrigation development. The presence of stones and boulders common to many coverage has been noted in some areas and the coverage of stoniness. The occurrence stones and boulders have been identified in particular in reddish brown soils. In sub surface stones and boulders has been found in some reddish ad dark reddish soils. 4.5 EROSION STATUS The rill and gully erosion are common in some places of the surveyed area. Mild to moderate sheet erosion is distributed in many locations. High level of gully, river bank and rill erosion have been noticed at vicinity of some intermittent stream. It WWDSE In Association with ICT Final Feasibility Study Report 21Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5- ANNEX 4 Soli Survey Study has been also noticed that considerable severe rill and gully erosion occurrence in the command area of Bale-Gadula. The major causes of soil erosion are known to be intensive rainstorm, human influence especially animal trucks, poor agricultural practices in the area and the erosion susceptibility nature of the existing soils in particular due to the sealing surface of the soil. WWDSE In Association with ICT Final Feasibility Study Ro port 22Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study 5. SOIL PHYSICAL CHARACTERISTICS 5.1 PARENT MATERIAL The soils studied area predominantly developed on alkaline olivine basalt and tuffs rhyolitees of lower Tertiary Trap Series by alluvial, colluvil and in situ weathered process of basaltic parent material 5.2 EFFECTIVE SOIL DEPTH Rotting conditions are controlled by soil effective depth and ease of root penetration. It is an important property for evaluating soils agricultural property. The soils, which are found in the project area, are categorized in to shallow, moderately deep, deep and very deep. The maximum depth ranges from 4.5 to 5 meters and the minimum depth is 25-50 cm. Deep to very deep soils are mainly found in almost to flat land of the command area. While shallow to moderately deep soils are situated gently to sloppy land. Most of the command area lies under very deep depth (>150 cm) category. 5.3 DEEP BORING To check the depth of the impervious horizon and to monitor the fluctuation of the water table 8 deep boring were made by auger boring from the bottom of the profile pits below 2m depth down to the depth of 3-5m on model profile sites. Out of eight profiles in three profiles achieved boring up to 5 meter depth. While in the remaining n two profiles had been made deep boring up to 2 - 3 meter depth and in three profiles did not achieved deep boring due to presence of stones. There have been collected 13 samples from 5 profile pits for determination of soil reaction and salinity. The result of the analysis indicated that the soil reaction is varying from moderately alkaline to strongly alkaline and the pH values are vary from 7.99 to 9.26 with an average of 8.62, indicating the presence of high pH value in the subsurface. Electrical conductivity (EC) of the soils, depicted by tests in deep borings found to be low. The value ranges from 0.58 mS/cm to 2.16mS/cm. This shows that soils are non-saline in substratum of the inspected profile. WWDSE In Association with ICT Final Feasibility Study Report 23Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study Table 5.1: Deep boring Profile Code Depth Jem) P -H2O h p -KCL H (1:2.5) (1:2.5) ApH EC(ms/cm) [1:2.5) BGP05 200-230 9.12 7.56 1.56 1.89 230-250 9.12 7.77 1.35 1.84 250-290 9.06 7.61 1.45 2.16 BGP35 200-240 8.46 6.97 1.49 1.25 240-370 8.12 6.85 1.27 1.13 370-450 8.68 7.09 1.59 0.95 BGP48 200-300 8.58 7.23 1.35 2.00 300-400 7.99' 6.90 1.09 1.82 400-450 8.11 6.92 1.19 1.68 BGP53 200-300 8.51 7.19 1.32 2.15 300-400 8.52 7.21 1.31 1.91 400-500 8.55 7.21 1.34 1.86 BGP68 200-245 9.26 7.60 1.66 0.58 Average 8.62 7.24 1.38 1.63 Min 7.99 6.85 1.09 0.58 Max 9.26 7.77 1.66 2.16 5.4 SOIL COLOUR Soil colour is the most perceptible facial appearance of the soils that can be without difficulty known by any person. It is related to precise chemical, physical and biological properties of the soils. The well drained soils of the study area have a color of, dusky red, Nitisols and dark reddish brown Luvisols. While the soils with imperfect drainage system are black and dark grey to grayish brown in colour (Vertisols). 5.5 SOIL TEXTURE Soil texture implies relative proportion of sand, silt and clay in the fine earth fraction-the soil material smaller than 2mm in diameter. It has been described by feeling method in the field and by hydrometer method in the laboratory. The overall textures of the investigated soils vary from sandy clay loam to clay on surface soil. While, in subsoil varies form loam to clay. The result of laboratory analysis showed that the clay on top soil varied from 29.4% to 73.57%, with an average value of 49.12%. The clay content increases in sub soil and ranging from WWDSE In Association with ICT Final Feasibility Study Rs port 24Federal Democratic Republic of Ethiopia- Ministry of Water Resources feasibility Study and Detail Design of Balo Gadula Irrigation Project VOL 5- ANNEX 4 Soil Survey Study 11.98% to 84.85% with mean value of 67.27%. The top soil content of sand is ranging from 9.62 to 53 76% with an average of 31.26%, while in sub soils it decreased and ranging from 9.50 to 52.74% with an average of 20.44%.The silt content in top soil is between 6.48 and 55 54%, where as its content decreases from 2.13 -62.37% wit an average of 12.29%. 5.6SOIL STRUCTURE In the project area, the top soil being black and dark gray color (Vertisols) are characterized by granular or blocky structures and moderately developed fine and medium singular or strongly developed prismatic structure at subsurface. In these soils, there is no hardpan or cementing materials in the surface and subsurface soil and as such compaction will not be a problem under careful machinery operation planning However, the upper layer of soils with red and reddish brown, including Luvisols have weak granular structure while the subsoil have moderate and medium sub angular blocky structure. 5.7 SPECIAL STRUCTURAL FEATURES It refers the presence of some special features like cutans and slickenside on the pedfaces. Predominantly on Vertisols have been recorded slickenside. Meanwhile it has been noted that clay cutans and shiny faces on pressure face of reddish soils. 5.8 CONSISTENCE Consistence refers to the response of soil material to applied force or pressure. The Vertisols are hard when dry, very firm when moist and very sticky and very plastic when wet, whereas the reddish to reddish brown clay soils (Nitisols & Luvisols) are hard when dry and very friable to friable when moist and slightly sticky and slightly plastic when wet. 5.9 SURFACE CRACKS Surface crack has been observed in most surveyed areas. Generally surfaceFederal Democratic Republic of Ethiopia- Ministry of Water Resources Feas I b i 11 ty Study and Detail Design of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study swelling clay soils (Vertisols). According to the field observations, the width of cracking ranges from fine (<1cm) to wide (2 to 10 cm). 5.10 BULK DENSITY Bulk-density of a soil is the weight of a known soil volume compared to the weight of an equal volume of water, or weight per unit volume. Bulk densities above 1.75g/cm2 for sandy and 1.46-1 63 gm/cm3 for silty and clays are quoted as causing hindrance to root penetration. Generally in normal soils bulk density ranges from 1.0-1.65g/cm3. In very compact soils, sometimes, it goes up to 2.0g/cm .To measure bulk density of the soils in Bale-Gadula irrigation project area undisturbed soil samples taken by using PF core sampling cylinder, were sent to Soil Laboratory The sub-soil bulk density of the soils is between 1.01 and 1.80 g/cm , the average value being 1.50g/cm . While, in substratum it varies from 3 3 3 1.17 to 1.94 g/cm3 with an average of 1.59 g/cm . Hence, in few places there 3 might be compaction problem. These high bulk densities have been measured on Vertisols. Vertisols have bulk density of 1.8 to 2.0 g/cm3 in the middle of the horizon and therefore are denser than most soils, probably resulting from repeated expansion and contraction which causes closer and closer packing. WWDSE In Association with ICT Final Feasibility Study Report 26Federal Democratic Republic of Ethiopia- Ministry of Wator Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5- ANNEX 4 Soil Survey Study 6. SOIL BIOLOGICAL CHARACTERISTICS 6.1 ORGANIC MATTER CONTENT Organic matter is taken as a crude indicator of fertility status of a soil. It is an important characteristic that influences the stability of soil structure and microbial activity. It has been determined by using Walkly and Black method in the laboratory and has been expressed in percentage (%).The value of organic matter has been obtained by multiplying the organic carbon content by factor 1.72 assuming that the soil organic matter contains 58% carbon. The overall organic carbon (C) content on surface soils, varied from 1.02%, to 6.97% with an average of 3.19%, indicating that the level of organic carbon is in high level. In most cases the organic C decreased with profile depth downwards. In present study the organic matter content on surface soil is between 1.75 to 11.99%, being an average is 5.49% and its content below surface soil is ranging from 0.17 % to 5.20% with an average of 2.56%. Generally, the organic matter is at high level. 6.2CONTENT OF ROOTS In dark gray soils with some what imperfect drainage the amount roots on upper surface are many, but in depth it is minimized. In the well drained reddish soils have many fine and medium and very few coarse roots have been observed mostly on the top soil up to the depth of 40-50cm. The abundance of roots decreased to deep depth and very few coarse and fine roots have been encountered in depths from 50 to 200cm. 6.3BIOLOGICAL FEATURES The evidence of biological activity is indicated, other than roots, by the presence of krotovinas- the irregular tubular infillings of the tunnels made by burrowing animals, insect casts/nests, termite colonies and snail shells etc. In the case of the present investigation the main biological features are the termite colonies and casts/nests However, the amount of termite or ant channels and nests are WWDSE In Association with ICT Final Feasibility Study ReportFodoral Democratic Ropublic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Projoct VOL 5- ANNEX 4 Soil Survey Study differing from soil to soil. The biological activity in reddish brown soil is more intensive than in dark grey to black soil due to favorable condition. The amount of ants and termite are mostly few in numbers in these soils. WWDSE In Association with ICT Final Feasibility Study Report 28Federal Democratic Republic of Ethiopia- Ministry of Water Resources Dotail Design of Bale Gadula Irrigation Project VOL 5- ANNEX 4 Soil Survey Study 7. SOIL HYDROLOGICAL CHARACTERISTICS 7.1 DRAINAGE The moisture condition of the Vertisols was slightly moist in topsoil up to 30cm deep but increasing downwards while other type of soils were dry and slightly moist. While the soils of upland and the hills are somewhat excessive drain (Leptosols) and well drained (Nitisols and Luvisols). The ground water table of the investigated area is very deep and there is not any record of occurrence of flooding in the area 7.2. INFILTRATION RATE Infiltration rate refers to the measurement of vertical intake of water into a soil surface and it is important parameters in design of irrigation system and soil conservation. The results are also used for determining the most efficient methods of applying irrigation and making runoff calculations. The measurement of infiltration rate was conducted by using of double ring infiltrometer method, which is de scribed in the FAO soils bulletin 42. It is the rate at which water enters the soil surface under given conditions. It is measured in the field for representative soils, generally using the Double-ring infiltrometer method. Infiltration is important for selection of suitable methods and design, selection of irrigation type, calculation deep percolation losses, irrigation efficiencies and crop water management. In the case of present work the rate of infiltration rate is ranging from 0.9 to 7.8 cm/hr with an average value of 2.86 cm/hr, showing that in most cases the result is with in the optimum range except at site profile pit BGP-05 only (see Table 7.1). 7.3 HYDRAULIC CONDUCTIVITY The soil hydraulic conductivity or permeability refers to the ability of a soil to transmit water through its body, vertically as well as horizontally. It was measured by using the Inverse Auger-hole method test described in the FAO soils bulletin WWDSE In Association with ICT Final Feasibility Study Report 29Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasi bIIIty Study and Detail Design of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study 42. The overall result of the hydraulic conductivity varying from 0.17 (slow) to 1.3 m/day (moderately rapid) and its mean value is 0.65 m/day (moderately slow) (see Table 7.1). Table 7.1: Summary of Infiltration Rate and Hydraulic Conductivity Measurement Profile Code SMU Texture Mean (cm/hr) HC (m/day) BGP-05 VB2VRpe-kB Sandy Clay Loam 7.8 0.04 BGP-18 VBIVRpekA clay 2.3 0.1 BGP-34 VB2LVeu-rB clay 3.3 0.12 BGP-35 VB2LVeUrB clay 0.9 0.07 BGP-39 VBILVeuB clay 1.00 0.11 BGP-48 VB2VRhyso-peB Clay 1.1 0.04 BGP-53 VBILPeuA Clay Loam 3.1 0.06 BGP-68 VB1VRso-kA Clay 51 0.07 7.4 FIELD CAPACITY If a=soil,-not under cultivation, is saturated and left to drain, the moisture stored in the pore space after drainage is known as field capacity. The moisture is held against gravity by a force known as moisture tension. The tension is expressed in equivalent atmosphere. One atmosphere is equal to a section or negative pressure of 1 kg/cm2. At field capacity soil retains moisture at about 1/3'd atmosphere. The field capacity of soil most necessarily depends on the soil texture. A fine textured soil will retain more water than a coarse textured soil. The field capacity value of the present work has not yet received. 7.5 PERMANENT WILTING POINT (PWP) Removal of soil moisture by crop roots reaches a stage when the soil particles exert a greater tension on the soil moisture than the crop roots can exert to extract the remaining moisture. When this condition is reached the soil is said to be at permanent wilting point. The corresponding soil moisture tension is about 15 atmospheres. The laboratory result PWP of the project area has not yet received. WWDSE In Association with ICT Final Feasibility Study Report 30Federal Democratic Republic of Ethiopia- Ministry of Water Resources feasibility Study and Detail Design of Bale Gadula Irrigation Project 7.6 AVAILABLE WATER CAPACITY VOL 5- ANNEX 4 Soli Survey Study Available water capacity (AWC) is the volume of water retained between field capacity and permanent wilting point. However, all available moisture is not accessible to plants due to imperfect drainage, hydraulic conductivity of soil, root concentration at different depths and stage of plant growth. A rule of thumb is that the readily available soil moisture is about two third of the total available moisture between field capacity and Permanente wilting point. To calculate AWC the following formula is used (FC - Plff) x horizondepth ,v BD AWC = ' 100 Table 7.2 shows the average available water capacity (AWC) and readily available water capacity (RAWC) value and textural, relationship of soils of the study area. However, laboratory analysis result has not yet received. AWC determines the available soil moisture content and the frequency of irrigation water to be applied, and thus a rating is done based on irrigation method requirement. Soils with AWC of above 140 mm within 1m depth are suitable for furrow irrigated agriculture and AWC of below 50 mm m’1 can not be irrigated (FAO, 1979; Sys et al., 1991b). In the case of the present study the analysis result is greater than 140 mm/m and thus the soil moisture condition is favorable for surface irrigation. — WWDSE In Association with ICT Final Feasibility Study Ro port 31\ 11 — U- L- Foderal Democratic Republic of Ethiopia- Ministry of Water Resources FeasIbllityStudyand Dotall Design of Balo Gadula Irrigation Project Table 7. 2: Water Holding Capacity of Bale Gadula VOL 5- ANNEX 4 Soil Survey Study FC PWP ---------- 1----------------- Profile code Depth (Cm) (0.33) Bar ' (15.0) Bar FC- PWP Thick. (mm) BD AWC (mm/m) % (Wt) % (Wt) Total AWC (mm/m) Texture Soil Mapping Unit 0-60 48.08 30.28 17.8 600 1.70 181 6 317 Sandy clay loam VB2VRpe-KB 60-100 47.63 28.77 18.86 400 1.80 135.8 clay BGP -05 100-160 46.77 28.73 18.04 600 1.75 189.4 clay 0-50 38.23 30.22 8.01 500 1.71 68.5 150 clay VB2LVeu-rB 50-100 37.27 28.61 8.66 500 1.88 81.4 clay BGP -34 100-150 37.76 28.67 9.09 500 1.70 77.3 clay 0-50 57.76 43.75 14.01 500 1.47 103.0 222 clay VB1VRso-kA BGP -68 50-100 58.23 39.81 18.42 500 1.29 118.8 clay 0-50 48.34 37.39 10.95 500 1.67 91.4 246 clay VB2LVeUrB BGP -35 50-100 57.98 38.42 19.56 500 1.58 154.5 clay 215 VBIVRpeKA 0-26 40.15 29.58 10.57 260 1.49 40.9 clay 26-77 42.94 29.94 13 510 1.90 126.0 clay BGP -18 77-160 36.19 25.47 10.72 830 1.94 172.6 clay 0-30 43.46 32.47 10.99 300 1.58 52.1 139 Sandy clay loam BGP -14 30-60 53.30 34.92 18.38 300 1.58 87.1 clay 0-30 45.05 33.15 11.9 300 1.35 48.2 135 Clay loam VBILPeuA BGP -53 30-70 48.33 36.14 12.19 400 1.56 76.1 clay 0-30 36.07 20.91 15.16 “. 300 1.37 62.3 165 clay VBILVeuB BGP -39 30-70 37.24"1 20.36 16.88 400 1.52 • 102.6 i clay WWDSE In Association with ICT Final Feasibility Study Roport 32Federal Democratic Republic of Ethiopia- Ministry of Water Resources feasibility Study and Detail Design of Bale Gadula Irrigation Projoct VOL 5- ANNEX* Soil Survey Study 8. SOIL CHEMICAL CHARACTERISTICS Chemical properties of soil, in general, influence the planning of agronomic development programs best suited to the proposed irrigation projects and evaluation and monitoring schemes. The chemical characteristics of soils have been analyzed and discussed on the basis of results of laboratory analysis of soil samples collected in the field. Ratings of all chemical parameter are presented in Annex 1, of this document. 8.1 SOIL REACTION pH value of soil is an important indicator, which describes acidity and alkalinity of the soil and the availability and toxicity of macro and micronutrients. pH value is determined by pH-meter in a 1: 2.5 soil-water suspensions. The overall pH value of all soils in the project area is between 6.33 and 9.35 with on average value of 8.30, while on top soil its value varies from slightly acidic pH= (6.33) to strongly alkaline (pH=9.07) with an average of 7.80 (moderately alkaline. In sub soil the soil reaction is varying from slightly acidic (pH=5.26) to strongly alkaline (pH=9.35) with an average of pH value of 8.48 Soil alkalinity is determined on the basis of contents of sodium, salt and CaCO3 found within the soils. In calcareous soils, the occurrence of CaCO3 is often associated with the presence of alkaline soil reaction. CaCO mainly exists in 3 the soil pH range of 7.0 to 8.5 and shows a tendency to raise the soil pH with increasing its concentration in the soil (Landon, 1984). Problems of phosphorus and micronutrients availability commonly occur in calcareous soils due to the effect of CaCO . 3 8.2 ELECTRICAL CONDUCTIVITY The electrical conductivity (EC) is measured in a saturation of extract of the soil water suspension using a conductivity meter. The electrical conductivity measurements are used as an indicator of total soluble salts in the soil. The EC of the project area varied from 0.05 to 0.56 with average of 0.18 mS/ cm. In general, the EC values indicate that the soils in the project area are free from salinity. Hence, EC should not be a constraint for any crop production. WWDSE In Association with ICT Final Feasibility Study Report 33Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Balo Gadula Irrigation Project VOL 5- ANNEX 4 Soil Survey Study 8.3 CALCAREOUSNESS The determination of free carbonate is used for soil classification of calcaric of calcic subunits of the FAO-UNESCO-ISRIC legend. The presence of free carbonate normally indicates that the clay complex is dominated by exchangeable Ca, which usually implies favorable soil physical conditions. The content of free carbonate (CaCO ) has been determined qualitatively at 3 field level by using a 10% HCI solution and quantitative analyses have also been done in laboratory. The presence of calcium carbonate affects both physical and chemical characteristics of the soil. Calcium carbonate can have the effect of increasing moisture diffusivity in soil, causing water movement to faster than in non- calcareous soils of similar particle size distribution. Again this effect is a function of the amount of CaCO3 present and the particle size. Up to 10 or 15% CaCO3 may assist formation of stable aggregate associated with relatively large pores and rapid water movement. In the case of present study this occurs in soil mapping units like VB2moVRca-peA, VB2haVRca-huC, VB1moVRca-wnA, VB1vrLPca-huC and PimoVRca-huC. With an increase content of CaCO3 up to 20 or 25% in the case of present work like soil mapping units VB2ccVRhu-peB, VB2so-ccVRhupeB, Piso-ccVRcr-stC, VB1so-ccVRhu-peA, VB2ccVRwn-peB, and PiccVRhu-peA, precipitation of carbonate within capillary tubes tends to increase the proportion of very small pores and reduce diffusivity. Surface crusting can be a serious problem in newly irrigated calcareous soils, especially those of low organic matter content. Crusts not only affect infiltration and soil aeration but also impede or prevent the emergence of seedlings. Heavy application of water on soils with a high content of fine-grained carbonates encourage the formation of thick crust will require a frequency irrigation sufficient to prevent drying and hardening of the soil surface. The laboratory results indicate that the over all carbonate content ranges between minimum value of trace and maximum value of 27.1% with an average value of 15.19% Out of the total 182 samples 167 samples have calcium carbonate value between 2.47 and 27.71% calcium carbonate, 67 samples have value greater than 15% calcium carbonate and 15 samples are trace level. Therefore, those soils with value greater than 15% are categorized as calcic soils and those soils with value between 2 and 15% are grouped as calcareous soils. WWDSE In Association with ICT Final Feasibility Study Report 34Federal Democratic Republic of Ethiopia- Ministry of Wator Resources study and Detail Design of Bale Gadula irrigation Project VOL 5-ANNEX 4 Soli Survey Study High levels of CaCO3 content (>15%) in the soil indicates that the clay complex is dominated by high level of exchangeable Ca, which can lead to deficiencies of micro-nutrients and antagonizing the action of other elements, particularly P, K and Mg. Phosphorus tends to be fixed as Ca - phosphate and becomes less available to plants due to alkaline reaction in calcareous soils. Besides, the existence of high CaCO3 concentration, particularly in the very fine fractions, brings risks of lime- induced chlorosis for many crops. This factor is well considered in the land quality rooting conditions and in avoiding interactions it is removed from being considering it in land quality salinity/alkalinity. 8.4 MINERAL NODULES On most soil profiles have been noticed common to many manganese and calcium carbonate nodules and concretion. While in Nitisols and Luvisols have been recorded ferro-manganese nodules and some times calcium carbonate nodules. 8.5 CATION EXCHANGE CAPACITY Cation Exchange capacity (CEC) is the capacity of a soil to attract and exchange species of positively charged ions (cations) in reversible chemical reactions with in the soil solution is a quality important for soil fertility and soil genesis studies. The CEC value was obtained by using ammonium acetate method at pH value 7 and in miliequivalent/100 gram of soil. Generally, the soils have very high CEC. The CEC value on top soil is ranging from 37.98 to 97.28 meq/100 gm of soil with mean value of 64.18 meq/100g of soil, while on sub-surface soils the average CEC is 59.08 meq/100 g soils and its maximum and minimum value is 82.30 and 25.30 meq/100g soil respectively. The high CEC of these soils indicate their richness of weathering and /or the less intensity of leaching and serves as a storehouse of nutrient for plant use. 8.6 BASE SATURATION The value of the Percentage Base saturation (PBS) is obtained by dividing the sum of exchangeable cations by Cation Exchange Capacity and is expressed in WWDSE In Association with ICT Final Feasibility Study Report 35Federal Democratic Republic of Ethiopia- Ministry of Water Resources F oa s I b i 11 ty Study and Detail Design of Bal^Gadula lrrigatlon Project^^ VOL 5-ANNEX 4 Soil Survey Study percentage. PBS value of 50% or above are referred to as "Eutric" and classified as high, while values below 50% are referred as Dystric low In general calculated value of base saturation of soils is between 61% and 206%, with an average of 115%. PBS on top soil is between 61 and 151% with an average of 104%. The PBS in sub-soil is between 63 and 205%. The PBS value exceeding 86.1% in the study indicates inflated conditions. It could be under estimated CECS of the soils are calcareous. Calcareous soils present a problem with ammonium acetate method as a consequence of the solubility of CaCO3 in the ammonium acetate solution giving lower value of CEC. This is because the dissolved Ca present in theNH OAC solution prevents complete saturation of 4 exchange positions with ammonium. 8.7 EXCHANGEABLE SODIUM (Na*) The overall content of exchangeable sodium on soil surface is between 0.13 and 12.66 meq/100 g soils Beneath surface its content increased downward the profile, ranging from 0.18 to 20.26 with an average of 7.08 meq/100g soil. Generally, the soils of the project area are at high level and thus, it will imply an adverse effect on soil properties and required to apply mitigation measure. 8.8 EXCHANGEABLE POTASSIUM (K*) Potassium has a counter balancing effect on the result of nitrogen excess. It enhances the synthesis and translocation of carbohydrates, thereby encouraging cell wall thickness and stalk strength. In studied soil in surface soils the content potassium varies from 0.32 to 19.35 meq/100g soil with an average of 1.67 meq/100 grams of soil. In subsoil its content is between 0.25 and 11.42 meq/100g soil, with a mean value of 0.88 meq/100g soils. In general the level of K is high to very high. The availability of potassium in the soil is usually judged by Ca + Mg/k ratio. If the ratio exceeds 40 there would be lack of K. The optimal range is 15 to 25. In the case of present study the ratio varies from 2.57 to 31926 with average of 94.55. In most cases the result of the analysis indicates that the deficiency of potassium and high content of Mg and Ca. The low content of K may be as a result of the nature of the parent material. Also, it has been indicated that K is in a WWDSE In Association with ICT Final Feasibility Study Report 36Federal Democratic Republic of Ethiopia- Ministry of Water Resources ^^sfblllty S£udy and Detail Dosign of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study fixed state. Since such fixation also means high K buffering c apa city, the low K content per se may not be enough to warrant any inadequacy for plant growth in soil of the project area. About 10 to 20% of such fixed K may be released dur ing 2 the cropping season. 8.9 EXCHANGEABLE CALCIUM (Ca *) Calcium is essential for the growth and functioning of root tips. It helps movement of carbohydrates from one part of the plant to the other and for helping to regulate sap acidity. According to the laboratory results, the content of exchangeable calcium on surface soil is varying from high (19.98 meq/100g soil) to very high (79.94 meq/IOOg soil) with an average of 53.36 meq/100 grams of soil. On sub soil the content of exchangeable calcium varies from 18.53 meq/100g soil to 66.12 meq/100g soil with mean value 44.57 meq/100g of soil. Generally, the level of calcium in most cases is very high 8.10 EXCHANGEABLE MAGNESIUM (Mg2+) Magnesium is a constituent of chlorophyll It is with other nutrient elements, a deficiency of magnesium results in characteristics discoloration of leaves. The top soils of the project area have low to high exchangeable magnesium varying from 0.90 to 23.50 meq/100 g soils with an average value of 10.49 meq/100 gram of soil. While, it’s content below surface is varying from 2.22 to 70.78 meq/100g soil, with an average value of 17.51 meq/100g soil. Thus, the over all status of exchangeable magnesium is very high. 8.11 CATIONIC RATIOS 8.11.1 Potassium to Magnesium Ratio (K: Mg) If the ratio of potassium to magnesium is more than 2:1, magnesium up take may be inhibited. The ratios of K and Mg on top soil as recorded for the project area range from 0.01 to 3.29, with an average value of 0.14, which indicates that the result is at recommended level. WWDSE In Association with ICT Final Feasibility Study Ro port 37Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feas I bllity Study and Detail Design of Bale Gadula Irrigation Project 8.11.2 Calcium to Magnesium Ratio (Ca: Mg) VOL 5-ANNEX 4 Soil Survey Study The minimum ratio of calcium to magnesium (Ca: Mg) in most soils of the project area is 0.43 while maximum is 60.0 with an average value of 5.08. Out of the total analyze samples 43% of the values of sample are between 1 and 3, showing that there would be inhibition of the uptake of phosphorus. Out of the total samples 24% is greater than or equal to 5, which indicates that the magnesium is increasingly unavailable to plants due to antagonistic effect of calcium and magnesium each other. This means that there is a high calcium level in these soils. Besides that there would be deficiency of phosphorus as a result high concentration of calcium. About 30% of the sample values are between 3:1 and 4:1 indicating that it is at optimum range for most crops. In few cases (about 3% is less than 1) the result showing that there would be calcium deficiency. 8.11.3 Potassium to CEC Ratio (K: CEC) Two percent of K: CEC ratio suggests a minimum level to avoid K deficiency and soils with more than 25% ratio is considered to be potassium rich soil. The minimum K: CEC ratio of the soil units in project area was 0.001 and maximum was 0.07 with an average value of 0.02. Hence, all the soils in the areas under investigation have the ratio less than minimum level which indicates K deficiency. 8.12 TOTAL NITROGEN Nitrogen is an essential nutrient element, which highly influences the plant growth. It is a constituent of chlorophyll, plant proteins and nucleic acid. The total nitrogen content of the project area has been determined by using kjeldahi method in the laboratory. The top soil total nitrogen of project area ranged from 0.08 to 0.69 % with an average of 0.34%. In the sub soil it varies from 0.12 to 0.31 % with an average of 0.12 %. Generally, the content of TNT is at very high level. 8.13 CARBON TO NITROGEN RATIO (C: N) Nitrogen most often controls the rate of organic matter decomposition; it is needed to build protein in new bacterial and fungal population. The nitrogen in microorganism and organic material is given as the carbon; nitrogen ratio. Soils or materials with small or narrow are relatively rich in nitrogen, while those with higher or wider ratios are relatively low in nitrogen. The plant residues with C: N WWDSE In Association with ICT Final Feasibility Study Report 38Federal Democratic Republic of Ethiopia- Ministry of Wator Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5- ANNEX 4 Soil Survey Study ratios 20:1 or narrower have sufficient nitrogen to supply the decomposing microorganism and to release nitrogen for plant use Residues with C: N ratios of 20.1 to 30:1 supply sufficient nitrogen for decomposition, but not enough to result in much release of nitrogen for plant use. The C: N ratio of humus ranges between 10 and 12, which is considered as a good quality of organic matter. The over all C: N ratio of the present work varies from 7 to 20 with an average of 10. The mean value of the C: N ratio is indicating that out of the total data most of the result is falling in to optimum range of organic level. 8.14 AVAILABLE PHOSPHORUS Available phosphorus is the amount of phosphorus readily available for nutrient absorption by plant roots. The content of available phosphorus on surface soil of the project area ranges from 0.07 to 42.18 ppm with an average value of 4.35 ppm, while the available P under surface soil varies from 0.01 to 33.52 ppm with an average value of 2.25 ppm. Thus, from the result it is possible to conclude that there is deficient of phosphorus. Therefore, phosphorus fertilizer is required. 8.15 SODICITY Exchangeable sodium percentage indicates sodicity in the soil. Soils with ESP <15% is generally non-sodic where as soils with ESP >15% is sodic and require amendment. Sodic soils are characterized by displacement of adsorbed ca2+, Mg24 and K4 on the cation exchange complex by Na4. This results in sealing of soils and impeding or slowing infiltration rate. Sodic soils are highly erodible as the excess sodium results in dispersal of clay minerals on contact with water with consequent structural deterioration. Such soils appear to be particularly susceptible to tunnel erosion. The maximal value of ESP on top the soil depth between 0 and 100 cm is ranging from 0.32 to 47.00% with an average value of 4.38%. Out of the total result most of the result are non sodic. However, some of the results are slightly sodic and the remaining is moderately sodic. The soil mapping units that are affected by sodicity problem are Piso-ccVRcr-stC, VB2so- ccVRhu-peB, VB1so-ccVRhu-peA, eroded phase and VB1so-ccVRhu-peA. So these soil mapping units are required amendment measure such as application of gypsum. WWDSE In Association with ICT Final Feasibility Study Report 39Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bate Gadula Irrigation Project VOL 5- ANNEX 4 Soil Survey Study 9. THE SOILS OF THE STUDY AREA 9.1. REVIEW OF PREVIOUS STUDIES This section presents the review of previous works, which were conducted in the Weiyb River Valley Previous soil studies of the project area range from site specific to basin wide and exploratory. The general and exploratory are countrywide studies that provided mapping of landforms and soils at 1:1,000,000 scale but which were largely exercised in imagery interpretation with a minimum of ground truthing. The other reconnaissance level soil study was also carried out at 1:250,000 scale as part of the Genele-Dawa River Basin Integrated Development Master Plan Study. This study was based on satellite imagery, aerial photo interpretation and some field investigations including the present project area. This section will give more attention for site specific studies and discussed briefly as follows. FAO/UNDP and WRDA 1992 The study area was located on the bank of upper Weyb River in Bale zone, Oromiya Regional State The organization conducted a pre-feasibility level of soil survey in 1992 over an area of 968 ha with an observation density of 1 per 4 ha and made a total of 156 augers boring up to the depth of 200cm along the transects at interval of 200m over a total length of about 14 km. A total of 7 pit descriptions dug up to 2meter depth, including soil sampling for laboratory analysis. Infiltration and permeability tests excuted in all seven soil profiles site and deep boring were done on 4 profile sites. Undisturbed core samples were taken from selected profiles for determination of moisture release characteristics (FC& PWP) and bulk density. The classification was conducted based on revised legend of the FAO-UNESCO soil map of the world, 1988/91. The study identified three major soil series. These are Kubsa soil series (Chromic-Hypo-Calcic Vertisols; FAO 1988/91, Asendabo soil series (Pellic- Hypo-Calcic Vertisols; FAO, 1988/91), Weib soil series (Pellic- WWDSE In Association with ICT Final Possibility Study ReportFederal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Doslgn of Balo Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study Eutric Vertisols; FAO 1988/9). In general, about 97% of the total area is covered by very deep, somewhat imperfectly drained, black brownish black, moderately to strongly alkaline, medium to high calcareous cracking clay soils. In addition, the document had also classified the soils in to three major irrigation suitability classes based on the soils features favoring irrigation. In total about 583 ha (60% of the total command area) classified as moderately suitable for irrigation development due to poor workability. About 995 ha (22% of the total area) is downgraded to marginally suitable as result steep slop and sodicity. The remaining 120 ha is downgraded to unsuitable because of steep slop and rock out crop. The study gave the following major conclusions and recommendation: • Considerable part of the project area about 401 hectare of land is covered by common to many stones and thus required removal of stones. • About 244 ha of land are in need of leveling or grading. In general, the study conducted by FAO/UNDP is found to be sufficient and has been conducted based on standards. The output of the study has valuable contribution and can be used as back ground information for the present study. However, since the investigation is made in smaller area than the present study and large area is not covered by the study. Thus, the present feasibility investigation is very essential to carry out verification and updating of the existing information with careful field checking. This will assist the project to provide updated and site specific information for the irrigation design work for the sites. 9.2 SOIL FORMATION The types of soils, which are developed in the study area is largely controlled by five major factors, including climate, living organisms, parent material, topography and time. These soils forming factors are also the cause of soil forming processes. The following processes are which are considered to be dominant in the surveyed area. WWDSE in Association with ICT Final Feasibility Study Report 41Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study Weathering is basically a combination of destruction and synthesis. Rocks are first broken down into smaller rocks and then into the individual minerals of which they are composed. Simultaneously, rocks fragments and the minerals therein are attacked by weathering forces and are changed to new minor modification or by complete chemical changes. As weathering is common in tropical area it goes smoothly in Bale-Gradual command area. Because of the high temperature and rainfall weathering process is relatively rapid. The weathering products vary from sandy loam to clay for the studied soils. Ferrugination releases of iron by weathering and dispersion of particles of iron oxide in increasing amounts, their progressive oxidation, giving the soil mass brownish, reddish brown and red colours respectively. In the Bale-Gadula irrigation project all the soils with good drainage have dark reddish brown colour because of ferrugination. Pedoturbation is the process of mixing in the soils. Pedoturbation is the common process in soils with vertic properties. As the result of pedoturbation slickensides and cracks are formed. In Bale-Gadula takes place mostly in dark clay soils (Vertisols). But in Nitisols pedoturbation is caused by termites, worms, small rodents etc. and by root action. 9.3 SOIL CLASSIFICATION SYSTEM The soil classification was carried out according to the World Reference Base for Soils Resources (FAO, 2006). Based on field morphological observation and laboratory analytical data the soils of area soils of the area have been classified on hierarchical system, with increasing specific criteria used to differentiate soils up to the lowest level of the system. The classification has three levels. At first level the classification is based on the recognition of diagnostic horizon, the second level on diagnostic properties and the third level is subdivided on the basis of diagnostic materials. Soil classification of the project area is based on field morphological characteristics, which were observed and measured or inferred from field observations. In addition to the morphological properties, physical and WWDSE In Association with ICT Final Feasibility Study ReportFederal Democratic Republic of Ethiopia- Ministry of Water Resources feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study chemical properties of the soils such as textural class, and content of free carbonate were used to define the soil classes. Soils were further subdivided based on soil phases, which indicate surface and subsurface features of land that have an impact on soil management and agricultural use The physiographic position, drainage characteristics of the soil, soil depth and textural classes were also important to the soil classification in the area. Accordingly the soils of Bale-Gadula Irrigation Project broadly fall into five major units, including, Leptosols, Nitisols, Luvisols, Vertisols and Cambisols. Nitisols and Luvisols occur on upper plains, while Vertisols occur on the lower plain. 9.3.1 Nitisols According to World Reference Base for Soil Resources 2006 soil classification Nitisols are soils having an argillic B horizon with diffuse horizon boundaries and subsurface horizon with more than 30% clay and moderate to strong angular blocky structure with shiny pedface. Nitisols are soils, which have B horizon with shiny pedefaces and an average clay distribution which does not show a relative decreases from its maximum of more than 20% within 150cm of the surface and their hues is 2.5YR and value (moist) less than 4. In this case the soil color is dusky red 2.5YR3/2) to dark reddish brown (2.5YR3/3). The soil textural class through out the profile is greater than 30%, with in the range of 36.5 to 93.3% with an average of 77.6%. The ratio of silt to clay is less than 0.4, with an average value of 0.2. The clay content of top soil is varied from 44.9% to 87.3 with an average of 66.4% while the clay of subsoil is greater by about 16% than the surface soil and it is ranging from 58.3 to 93.3% with an average of 82.5%. The minimum pH value is 4.02 and the maximum is 6.2 with an average value of 5.2. As a result the soil reaction is strongly to slightly acid. The organic matter is ranging from 1 to 6.1 with an average of 4.1%, indicating that it is at high level. The TNT is at high level and varied from 0.09 to 0.36 with an average of 0.36%. The average of proportion of organic carbon to total nitrogen (C/N) is 13. The available phosphorus is low with average value of 7.9ppm on top soil. The Nitisols WWDSE In Association with ICT Final Feasibility Study Roport 43Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soli Survey Study of the project area is reclassified as Haplic Nitisols (Humic). Nitisols have covered 718 hectares of land and constitute 9.3% out of the total command area. Haplic Nitisolsols (Humic) Nitisols having that organic carbon contents in the fine earth fraction as a weighted average: in 1.4 percent or more to a depth of 100 cm from the mineral soil surface. 9.3.2 Luvisols The other soils, present in the project area, are Luvisols. It occupies 800 ha and took about 10% out of the total area. The Luvisols are deep to very deep, dark reddish brown, sandy clay and silty clay over clay. These soils are characterized by well drainage, many fine and medium pores with faint cutanic features on the 'B' horizon. They are distributed on flat plain and occupy -ha and form -% out of the total irrigable area. The color of the soil is dark brown ((7.5YR %) to brown (7.5YR4/4). The clay content of top soil is varied from 28.6 to 67.01 with an average value of 39% while in sub soil the clay content is increasing and its value varied from 12.34 to 61% with an average of 40.5%. The soils have high level of organic matter, which varies from 1.68 to 7.41% with an average of 3.24%.The bulk density of the Luvisols of the project area is ranging from 1 14 to 1.74 with an average value of 1.50. The soil reaction is slightly to very acidic (pH=5.6 to 7.7). The minimum value of total nitrogen is 0.14 and the maximum value is 0.46 and its average is 0.23%, indicating that the status of the nitrogen is at medium level. The proportion of organic carbon and nitrogen is 8. The content of available phosphorus is very low, ranging from 0.2 to 3.16 ppm. This soil has high CEC with an average value of 21.06 meq/100 g soils and the BSP is 60%. Luvisols subdivided in to three units, namely Haplic luvisols (Hypereutric, Clayic), Haplic Luvisols (Hypereutric, Chromic) and Calcic Luvisols (Hypereutric, Chromic). WWDSE In Association with ICT Final Feasibility Study Roport 44Federal Democratic Republic of Ethiopia- Ministry of Water Resources .FeaslbH lty_Study and Detail Design of Bale Gadula Irrigation Project VOL 5- ANNEX 4 SoM_Sunzey_Stucty_^ Hapli c Luvisols (Hypereu tric, clayic) Soils those have typical Luvisols characterist ics with a base saturation of greater than 50 percent through out between 20 and 50 cm from the soil surface and a texture of clay in a layer, 30 cm or more thick, within 100 cm of the soil surface. Haplic Luvisols (Hypereutric, Chromic) Luvisols that having a base saturation of greater than 50 percent throughout between 20 and 50 cm from the soil surface and a Munsell hue redder than 7.5 YR or that has both, a hue of 7.5 YR and a chroma, moist, of more than 4. 9.3.3 Vertisols Vertisols are dark montmorillonite-rich clays with characteristic shrinking/swelling properties. This group of soils with a high clay content (>30% to at least 50 cm from the surface) and in dry state with typical cracks which are at least 1 cm wide and reach a depth of 50 cm or more, are often also called heavy cracking clay soils. Vertisols are a Reference Soil Group of the World Reference Base (WRB) soil classification system. A vertisol is a soil with dark gray to black and very dark grayish, brown to dark brown color, clay to heavy clay and deep to very deep, in depth with imperfect to poor drainage. Vertisols owe their specific properties to the presence of swelling clay minerals, mainly montmorillonite. As a result of wetting and drying, expansion and contraction of the clay minerals take place. Contraction leads to the formation of the wide and deep cracks. The cracks close after rain when the clay minerals swell During expansion of the clay minerals high pressures are developed within these soils, causing a characteristic soil structure with wedge-shaped aggregates in the surface soil and planar soil blocks in the subsoil. The slippage of one soil block over the other leads to the formation of typical polished surfaces, "slickensides" on the blocks. Expansion and contraction also cause the formation of micro-topographic features known as "gilgai", a distinctive microrelief of knolls and basins that develops by internal mass movements in the soil and heaving of the underlying material to the surface. WWDSE In Association with ICT Final Feasibility Study Report 45Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Balo Gadula Irrigation Project VOL 5- ANNEX 4 Soil Survey Study Vertisols are the most extensive soil units in the command area, covering 5452 ha of land, which constituting about 71% of the total area. The Vertisols of the project area have clay texture through out the profile with greater than 30% and it ranges from 22.75 to 88.75% with an average of 51.26% on top soil. In sub soils it is varying from 42 23 to 93.67%. The consistence of Vertisols is extremely hard when dry, friable during moist condition and very sticky and very plastic when wet These soils crack widely with 2-3 cm width during the dry season. However, the cracks close up again on rewetting and as a result of this expansion and contraction forms grooved shiny pedfaces, known as slickenside and granular over sub-angular blocky structure. The bulk density is ranging from 1.3 to 1.90 g/cm with an average of 1.67 g/cm 3 3 These soils are predominant in the study area. They are difficult to till and require greater skill in management for better production than any soils in the study area. Vertisols occur on flat and almost flat land and developed on basic rocks and alluvial deposits. Soil reaction of this Vertisols ranging from slightly alkaline (pH=5.89) to strong alkaline (pH=8.89). The organic carbon on surface soil varied from 0.83 to 7.3% with an average of 2.8%, showing that the soil has low to medium level organic carbon content. It has medium level total nitrogen with an average of 0.26% and the proportion of organic carbon to nitrogen ranging from 6 to 21 with an average value of 11.On top soil the CEC value is varying from 31.2 to 80.4 meq/100g soil with an average value of 69.62 meq/100g soil and Ca to Mg ratio varies from 1 to 57 with average of 4. The average available content of phosphorus is very low and its value is 3.27 ppm. The Vertisols in the project area is sub divided in to Eutric, Calcareous, Calcic, Sodic and Hyposodic Vertisols. Calcic Vertisols (Humic, Pellic) Vertisols, those having 15% or more calcium carbonate and organic carbon contents in the fine earth fraction as a weighted average 1 percent or more to a depth of 50 cm from the mineral soil surface with a Munsell value, moist, of 3.5 or less and a chroma, moist, of 1.5, clay in texture angular and sub angular blocky structured and well to imperfectly drain. WWDSE In Association with ICT Final Feasibility Study Report 46Fedoral Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project Sodi-Calcic Vertisols, (Humic, Pel lie) VOL 5- ANNEX 4 Soil Survey Study Vertisols having that 15% or more ESP and 15% or calcium carbonate with organic carbon contents in the fine earth fraction as a weighted average 1 percent or more to a depth of 50 cm from the mineral soil surface with a Munsell value, moist, of 3.5 or less and a chroma, moist, of 1.5, clay in texture angular and sub angular blocky structured and well to imperfectly drain. Sodi-Calcic Vertisols, (Chromic) Vertisols having that 15% or more ESP and 15% or calcium carbonate with a Munsell hue redder than 7.5 YR or that has both, a hue of 7.5 YR and a chroma, moist, of more than 4. Calcic Vertisols (Pellic) Vertisols, those having 15% or more calcium carbonate and a Munsell value, moist, of 3.5 or less and a chroma, moist, of 1.5, clay in texture angular and sub angular blocky structured and well to imperfectly drain. Calcic Vertisols (Hyposodic, Chromic) Vertisols, those having 15% or more calcium carbonate and 6% or more ESP on the exchangeable complex in a layer, 20 cm or more thick, with in 100 cm of the soil surface with a Munsell hue redder than 7.5 YR or that has both, a hue of 7.5 YR and a chroma, moist, of more than 4. Haplic Vertisols (Calcaric, Humic) Typical Vertisols those have material that conatins 2 percent or more calcium carbonate equivalent between 20 and 50 cm from the soil surface and organic carbon contents in the fine earth fraction as a weighted average 1 percent or more to a depth of 50 cm from the mineral soil surface. Mollie Vertisols (Calcaric, Pellic) A Vertisol that having material that contains 2 percent or more calcium carbonate equivalent between 20 and 50 cm from the soil surface and a Munsell value, WWDSE In Association with ICT Final Feasibility Study Report 47Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study moist, of 3.5 or less and a chroma, moist, of 1.5, clay in texture angular and sub angular blocky structured and well to imperfectly drain. Calcic Vertisols, (Hposodic, Pellic) Vertisols, those having 15% or more calcium carbonate and 6% or more ESP on the exchangeable complex in a layer, 20 cm or more thick, with in 100 cm of the soil surface with a Munsell value, moist, of 3.5 or less and a chroma, moist, of 1.5, clay in texture angular and sub angular blocky structured and well to imperfectly drain. Mollie Vertisols (Calric, Hyposodic) Vertisols that have a thick, well-structured, dark-colored surface horizon with a high base saturation and a moderate to high content of organic matter and material that contains 2 percent or more calcium carbonate equivalent between 20 and 50 cm from the soil surface with 6% or more ESP on the exchangeable complex in a layer. Mollie Vertisols (Calcaric) A Vertisol that has a thick, well-structured, dark-colored surface horizon with a high base saturation and a moderate to high content of organic matter and material that contains 2 percent or more calcium carbonate equivalent between 20 and 50 cm from the soil surface. 9.3.4 Leptosols Leptosols accommodate very shallow soils over hard rock that is extremely gravelly and I or stony. They are a zonal soils with incomplete solum and / or without clearly expressed morphological features. It is sub grouped in to Eutric Leptosols. The Leptosols identified in the project area is Vertic Leptosols (Calcaric, Humic). It occupies a portion of land of the command area, covering about 53ha of land. WWDSE In Association with ICT Final Feasibility Study Roport 48Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula irrigation Project Vertic Leptosols (Calcaric, Humic) VOL 5-ANNEX 4 Soli Survoy Study Leptosols those having material that contains 2 percent or more calcium carbonate equivalent between 20 and 50 cm from the soil surface with organic carbon contents in the fine earth fraction as a weighted average 1 percent or more to a depth of 50 cm from the mineral soil surface. Table 9.1: Soil Units and their Distribution in the Bale-Gadula Command Area Area Sr No. Major Soil Units Soil Units Ha % 1 Calcic Vertisols (Humic, Pellic) 313 4.1 2 Calcic Vertisols (Humic.Pellic) 98 1-3 3 Calcic Vertisols (Hyposodic, Chromic). 607 7.9 4 Calcic Vertisols (Pellic) 815 10.6 5 Calcic Vertisols. (Hposodic, Pellic 445 5.8 6 Haplic Vertisols (Calcaric-Humic) 206 2.7 7 Mollie Vertisols (Calcaric. Humic) 225 2.9 8 Mollie Vertisols (Calcaric, Pellic) 857 11.1 9 Mollie Vertisols (Calric. Hyposodic) 468 6.1 10 Sodi-Calcic Vertisols. (Chromic) 610 7.9 11 Sodi-Calcic Vertisols. (Humic.Pellic) 88 1.1 12 Vertisols Sodi-Calcic Vertisolsols (Humic. Pellic) 721 9.3 - 5452 70.6 13 Leptosols ---------------------------- Vertic Leptosols ( Calcaric, Humic) 53 0.7 14 Haplic Luvisols (Hypereutric. Chromic) 532 6.9 15 Haplic Luvisols (Hypereutric. clayic) 200 2.6 16 Luvisols Calcic Luvisols (Hypereutric, Chromic) 67 0.9 800 10.4 17 Nitisols Haplic Nitisolsols (Humic) 718 9.3 18 Ridge 699 9.0 7722 100 WWDSE In Association with ICT Final Feasibility Study Roport 49652000 664000 FEDERAL DEMOCRATIC REPUBLIC OF ETHIOPIA MINISTRY OF WATER RESOURCES WELMEL, YADOT AND BALE GADULA IRRIGATION PROJECTS PROJECT BALE GADULA IRRIGATION PROJECT CONSULTANT WATER WORKS DESIGN AND SUPERVISION ENTERPRISE SUB CONSULTANT • INTERCONTINENTAL CONSULTANTS AND | TECHNOCRATS PVT. LTD _ MAP TITLE Soil Units map DATE SCALE Figure Q December, 2009 1:80,000 ’’1 652000 664000 676000 792000Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study 10. SOIL MAPPING UNITS The soils are categorized into 19 soil mapping units by using the following differentiating criteria: ■ Physiographic position (terraced, depression or concave surface) • Micro-topography (termites, gilgai) • Surface slope • Surface texture ■ Soil depth • Erosion hazard ■ Stoniness • Chemical characteristics (sodiciy and calcareousness) The map legend has been prepared based on the data obtained from field survey and laboratory analysis. The map unit has been drawn on the basis of the land characteristics such as soil depth, slope class, land form, water logging and stoniness. 10.1 LEGEND FORMATION The legend to the soil mapping units was structured at three levels of generalization in hierarchical order, namely geomorphic units (land form) - level 1; soil units - level 2, and phases (flooding & erosion) - level 3. The mapping unit symbols representing the three elements were designated by upper and lower case letters as follows: • First upper case letters with arabic number showing the first level of generalization (geomorphic units) • Second Upper case letters showing the second level of generalization (soil units class) • Third upper case letters showing the third level of generalization (Slope). Example: -Geomorphic unit (Gently Undulating Plain) r~ VB1 VRso A Soil unit (Sodic Vertisols) Slope class (2-4%) WWDSE In Association with ICT Final Feasibility Study Report 51Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Balo Gadula Irrigation Project 10.2 DESCRIPTION OF SOIL MAPPING UNITS VOL 5- ANNEX 4 Soil Survey Study In this section the description of each soil mapping units and their extent and distribution have been presented in table 10.1. The soil variation in the project area mainly depends on land and physiographic position. The landscape of the project area is grouped into four based on landform and presence of termites i.e. very genteel to gently undulating plain. Table 10.1: Legend Description Mapping Units Description VB2ccVRhu-peB Very deep, clay, very dark gray (10 YR3/1) over black (10YR 2/1), imperfectly drained strongly develop sub-angular blocky-structure, Consistency is hard when dry, friable when moist and slightly sticky and slightly few or no stones, developed on gently undulating plain (1-2%), (Calcic Vertisols (Humic,Pellic) ........... VB2so-ccVRhu-peB Very deep, clay, very dark gray (10YR 3/2) over very dark grayish brown (10 YR3/1), imperfectly drained, common stones and boulders, sub- angular blocky structure, Consistency is hard when dry, friable when moist and slightly sticky and slightly , gently undulating plain (1-2%), ( Sodi-Calcic Vertisols, (Humic,Pellic) Piso-ccVRcr-stC Very deep, clay, very dark grayish (10 YR3/2) to very dark brown (10YR2/2), imperfectly drained, fine granular over angular to sub angular blocky structure. Consistency is hard when dry, friable when moist and slightly sticky and slightly few and Common stones and boulders, slightly eroded, developed on piedmont plain (2-4%), (Sodi-Calcic Vertisols. (Chromic), stony phase PiccVRpeC Very deep, clay, very dark gray (10YR 3/1) over black (10YR2/1), somewhat imperfectly drained, granular structure over sub-angular blocky structure, Consistence is hard when dry, friable when moist and slightly sticky and slightly, slightly eroded and Common stones and boulders, strongly calcareous, developed on piedmont plain (2-4%), (Calcic Vertisols (Pellic). eroded phase VB1ccVRwn-crA Very deep, sandy clay loam over clay, , black (10YR 2/1) over very dark brown (10YR 2/2), imperfectly drained, sub angular blocky structure, Consistence is hard when dry, friable when moist and slightly sticky and slightly plastic, Common stones and boulders, developed very gently undulating plain (0-1%), (Calcic Vertisols (Hyposodic, Chromic). VB2haVRca-huC Very deep, clay loam over sandy clay loam, dark gray (10YR 4/1) over very dark gray (10YR 3/1), imperfectly drained, fine granular over sub- angular blocky-structure, common surface stones, developed on gently undulating plain (2-4%), Haplic Vertisols (Calcaric-Humic) stony phase VB2moVRca-peB Very deep, clay, very dark gray (10YR 3/1) over very dark brown (10YRR 2/2), some what imperfectly drained, weak fine granular over moderate fine and medium sub-angular blocky structure, common to many surface stones, extremely calcareous, developed on gently undulating plain (1-2%), (Mollie Vertisols (Calcaric, Pellic). WWDSE In Association with ICT Final Feasibility Study Report 52Federal Democratic Republic of Ethiopia- Ministry of Water Resources feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study VBIccVRpeA Very deep, clay, dark gray (10YR 4/1) over dark brown (10YR3/3), somewhat imperfectly drained, sub-angular blocky structure, moderately eroded and common stones and boulders, developed under dense shrubby wood land on nearly level (0-1%), (Calcic Vertisols (Pellic VB1so-ccVRhu-peA Very deep, clay, very dark gray (10YR3/3) over black (10YR2/1), fine moderately developed sub-angular blocky over medium moderately developed sub-angular blocky structure, common surface stones and boulders, developed on nearly level (0-1%), Sodi-Calcic Vertisols, (Humic,Pellic) VB2haNThu-stB i very deep, sandy clay over clay, sandy clay over clay), well drained, fine weakly developed sub-angular blocky structure, strongly calcareous, common surface stones and boulders, developed under on very gently undulating (1-2%), (Haplic Nitisols (Humic) stony phase VB2ccVRwn-peB Very deep, clay, very dark gray (10YR 3/1) over very dark brown (10YR 2/2), imperfectly drained, sub angular blocky structure, moderately eroded, developed under on very gently undulating (1-2%), Calcic Vertisols, (Hposodic, Pellic VB1moVRca-wnA Very deep, clay, very dark grayish brown (10YR 3/2) over very dark gray (10YR3/1), imperfectly drained , weak fine granular over moderate medium sub angular blocky structure, few surface stones developed on nearly level land (0-1%), (Mollie Vertisols (Calric, Hyposodic) VB2haLVhe-crB Very deep, clay, very dark grayish brown (10YR4/2) over dark brown (7.5 YR 3/2), well drained , moderate medium granular over sub angular blocky structure, many stones and boulders, developed on very gentle undulating (1-2%), Haplic Luvisols (Hypereutric, clayic) Stony phase VB1haLVhe-crB Very deep, clay, 7.5YR 3/3) over very dark brown (7.5YR2.5/2), well drained, moderate medium granular structure over strong medium to coarse sub-angular blocky, extremely calcareous, developed on very gentle undulating land (1-2%), (Haplic Luvisols (Hypereutric, Chromic)). PiccLVhe-crC Very deep, clay loam over clay, dark brown (7.5YR 3/2) over very dark brown (7.5YR3/1), well drained, sub angular blocky structure, moderately sodic. developed on piedmont plain (2-4%), (Calcic Luvisols (Hypereutric, Chromic). VB1vrLPca-huA shallow, silty clay loam, is very dark grayish brown (10 YR3/2), excessively drained , moderate fine granular and/or wedge shape over sub angular blocky structure, extremely calcareous, very few on non stones, developed on nearly level to level (0-1%), Vertic Leptosols ( Calcaric, Humic) PiccVRhu-peA Very deep, clay, very dark gray (10YR3/1), imperfect drained , moderate fine granular over sub angular blocky structure, extremely calcareous, common to many surface stones, developed on nearly level to level (0- 1%),Calcic Vertisols (Humic. Pellic), Stony phase PimoVRca-huC Very deep, clay, very dark gray (10YR 3/1) over black (10YR2/1), imperfect drained , moderate fine granular over sub angular blocky structure, extremely calcareous, very few on non stones, developed on undulating sloppy land (2-4%), Mollie Vertisols (Calcaric, Humic) VB1so-ccVRhu- peA Very deep, clay, black (10YR 2/1) over dark gray (10YR3/1), imperfect drained , moderate fine granular over sub angular blocky structure, extremely calcareous, very few on non stones, developed on nearly level and (0-1%), (Sodi-Calcic Vertisolsols (Humic, Pellic), WWDSE In Association with ICT Final Feasibility Study Report 53Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project 10.2.1 Soil Mapping Units VB2ccVRhu-peB VOL S- ANNEX 4 Soil Survey Study This unit refers to Calcic Vertisols (Humic, Pellic) and developed on the foot slopes within the slope range between 1 and 2%, under cultivated land. It is subjected to colluvial processes. The total extent of the unit is 98 ha (1.3%). The soils are very deep (>200 cm), imperfectly drained, very dark gray (10 YR3/1) over black (10YR 2/1) and the soil texture is clay loam over clayey, which the clay the content is 39.48%. Clay increases with depth. Consistencies are hard when dry, friable when moist and very sticky and very plastic when wet Surface soils have moderate medium angular blocky structure, while subsurface soils have weak to moderate medium sub angular blocky structure. The cracks were developed to a depth of about 90 cm in all the studied profiles. Their width at the soil surface ranged from 3 to 6 cm. Slickensides were observed and the paralleled structures were attributed to the soil texture, swelling, and shnnkage and pedoturbation in these soils. The infiltration rate is 7.8 cm/hr and it is marginally suitable. The hydraulic conductivity value is very slow with an average value of 0.19 m/day. The water holding capacity is 135 mm/m. The pH result on surface soils are strongly alkaline (pH=8.87) and values decrease with depth (pH=8.25). A value of EC is 0.99 mS cm-l indicating that these soils are not saline. Base saturation is greater than 100% throughout the soil profiles due to the presence of free CaCO3. The CEC is very high with value of 53.06 meq/100g soil on top soil. Under sub soils it increased with depth along with clay content of the soils. The organic C and total N values are 4 64% and 0.49% respectively and decreased with depth. The C/N ratios are 10. Available phosphorous value is 5.51 ppm and decreased with depth. The upper horizons showed lowest values and levels of phosphorous were not adequate in soils of this mapping unit. Ca values are 43.84 meq/100 g soils and increased to Bw horizons up to 54.24 meq/100g soil, indicating that the level of calcium is very high. Mg values are 5.88 meq/100 g soils and increased with depth and highest in the Bk horizons. The value of free carbonate in upper horizon up to depth of 125 cm is 27.71%, indicating that the soils are calcic. The ratio of Ca: Mg is 7, indicating that it is at recommended level for many crops. The proportion of potassium to magnesium is 3.3, it is favorable fro vegetables crops. WWDSE In Association with ICT Anal Feasibility Study Rspon 54Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study Model Soil Profile Description Profile code: BGP-02 Mapping unit: VB2ccVRhu-peB Status: Sampled profile Date: 25/06/09 Soil classification, FAO (2006): Calcic Vertisols (Humic, Pellic) Coordinates, Long (N): 0766767, Lat (E): 0650372, Elevation: 2024 Author: Addisu Land form: Plateau terrace Relief intensity: <100 Map sheet No. Regional slope: Flat to gently undulating Depth to bedrock: 0740 C4 >200 cm Slope class: Very gently slope to gently Rock out crops: None Surface coarse fragments: None Position: Medium Surface cracks: Wide Micro topography: Level Surface sealing: weak Parent material: Alluvial deposits Slope form: Convex cultivated land Effective soil depth: Very deep cultivation Drainage class: Moderate well drained Drainage external: Well Water table: None Flooding: None Land cover: Settlement & Intensively Land use: Residential use & Rain fed arable Fertilizers: None Erosion status: None 0-30 cm: Very dark gray (10YR 3/1) when moist; clay loam texture; moderate fine and medium granular structure, very friable when moist, sticky & plastic when wet; abundant fine and medium roots, common termite or ant channels and nests; abundant fine and medium pores; extremely calcareous; clear and smooth boundary. 30-80 cm: Black (10YR 2/1) when moist; clay texture; strong medium & coarse structure; firm when moist, very sticky & very plastic when wet; patchy faint clay jeommon fine and medium roots; many fine pores; extremely calcareous cutans ;clear and smooth boundary. 80-140 cm: Very dark grayish brown (10YR 3/2) when moist; clay texture; strong medium & coarse columnar structure; friable when moist, very sticky & very plastic when wet; continuous prominent slickensides; few fine roots; common fine pores; extremely calcareous; clear and smooth boundary. 140-200 cm: Dark brown (10YR 3/3 )when moist; clay texture; strong medium & coarse columnar & angular blocky structure; friable when moist, very sticky & very plastic when wet, continuous prominent slickensides; many reddish brown soft carbonate segregation ; very few very fine roots; common fine pores; extremely calcareous . WWDSE In Association with ICT Final Feasibility Study Roport 55Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study 10.2.2 Soil Mapping Unit VB2so-ccVRhu-peB This unit refers to Sodi-Calcic Vertisols, (Humic, Pellic) and developed on the foot slopes within the slope range between 1 and 2%, under cultivated land The mapping unit covers an area of 209 ha or 2.7% of the project area .The soil texture of this unit is sandy clay loam to clay on surface soil. The clay content on surface soil varied from 32.4 and 52.92% with an average of 44.5%. Under surface soil the clay content is increases and reaches up to 83.85%. It is very deep (>150 cm) with imperfectly drained and common stones and boulders on surface. The colour of the soils is very dark gray (10YR 3/2) on surface soil and under surface soil it is very dark grayish brown (10 YR3/1). The Land cover is open shrub land with sparsely cultivated land. The soils have moderate fine and medium granular structure on top soil and moderately to strongly develop sub- angular blocky-structure in sub-surface soil. Consistence is hard when dry, friable when moist and very sticky and very plastic when wet. The cracks were developed to a depth of about 90 cm in all the studied profiles. Their width at the soil surface ranged from 3 to 6 cm. Slickensides were observed and the paralleled structures were attributed to the soil texture, swelling, and shrinkage and pedoturbation in these soils. The infiltration rate is 7.8 cm/hr, which is marginally suitable for surface irrigation. The hydraulic conductivity is 0.19 m/day (slow). The bulk density is on surface soils varied from 1.23 to 1.70 g/cm3 and it increased with depth, ranging from 1.50 to 1.92 g/cm3. The water holding capacity of this mapping unit is 317 mm/m and rated as very high class. The pH values on upper horizon ranged from 7.11 to 8.67 and increased with depth up to pH=9.28. The upper horizon showed that the soil reaction of this unit is slightly to strongly alkaline. Values of EC ranged from 0.10 to 0.19 with an average of 0 15 mS/cm on upper surface and increased with depth up to (0.14 to 2.16 mS/cm), showing that in general the soils are non-saline. Values of ESP varied from 11 to 23%, indicating that the soils are sodic. Thus, these soils are required gypsum application. The soils have very high CEC on top soil and the value varied from 59.42 to 79.37meq/100g soil with an average of 68.78 meq/100g soil. Under surface soil it is also very high 45 to 78.4 meq/100g. The WWDSE In Association with ICT Final Feasibility Study Report 56Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study base saturation is very high and exceeding 100% through out the profile due to the presence of free CaCO3 The organic carbon is very high varied from 2.47 to 3.98% on surface soil. While under surface it decreases (1.24-3.02%). The value of total nitrogen on top soil is y high with values ranged from 0.19 to 0.38% with an average value of 0.27%. Beneath surface soil it decreases (0.06-0.2%). The ratio of organic carbon to nitrogen varied from 10 to 13. The available phosphorus on surface soil is very low with values ranged from 1.14 to 3.83 ppm, and it decreases in sub soil and its value ranged from 0.54 to 8.40 ppm. The concentration of CaCO varied from 3 12.9 to 27.15% with an average value of 18.82%. These soils have high exchangeable sodium, rating from 0.14 to 1.47 meq/100g soil on surface soil. Beneath surface soil it increases considerably and its value reaches up to14.61 meq/100g soil. Thus, it might have an adverse effect on soil property. The exchangeable potassium ranged from 0.98 to 3.10 meq/100g soil with mean value of 1.64 meq/100g soil on top soil. Under surface soil it's varied from 0.43 to 2.79 meq/100g soil, showing that the soils have very high exchangeable potassium. These soils have very high calcium content with values rated from 43.46 to 60.48 meq/100g soil on top soil. Under surface soil there its amount slightly decreased and the values varied from 31.36 to 65.41 meq/100 g soils. The magnesium level also vey high with value ranged from 7.62 to 11.65 meq/100g soils with mean value of 10.19 meq/100g soil on surface soil and in sub-soil it is increases slight (3.58 -21.95 meq/100g soil with mean value of 11.74 meq/100g soils. The ratio of Ca: Mg is between 5 and 6 as a consequence the availability of magnesium and phosphorus may be inhibited due to high concentration of calcium. The proportion of potassium to magnesium is 0.15 and it is favorable for vegetables crops. WWDSE In Association with ICT Final Feasibility Study Report 57Fodoral Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Dotail Design of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study Model Soil Profile Description Profile code: BGP-05 Mapping unit: VB2so-ccVRhu-peB Status: Sampled profile Date: 27/06/09 Soil classification, FAO (2006): Sodi-Calcic Vertisols, (Humic, Pellic) Coordinates, Long (N): 0786702, Lat [E):0653113, Elevation: 1946 Author: Addisu Land form: Valley floor Relief intensity: <100 Regional slope: Flat Map sheet No. 0740 C4 Slope class: Level Slope form: Uniform Depth to bedrock: >290 cm Rock out crops: None Surface coarse fragments: Common stones Position: Low Surface cracks: Wide Micro topography: None Surface sealing: Weak and moderate Parent material: Alluvial deposits Land cover: Open shrub land & intensively cultivated land Effective soil depth: Very deep grazing Land use: Rain fed arable cultivation & extensive Drainage class: Moderate well drained Fertilizers: Drainage external: slow Water table: None Flooding: None Erosion status: None None 0-20 cm: Very dark grayish brown (10YR 3/2) when moist; silty clay texture; weak fine granular structure; friable when moist, very sticky & very plastic when wet; few fine roots; abundant fine and medium pores; extremely calcareous, clear and smooth boundary. 20-95 cm: Very dark gray (10YR 3/1) when moist; clay texture; moderate medium angular blocky structure; friable when moist, very sticky & very plastic when wet continuous prominent slickenside; common white soft carbonate segregation; few fine and medium roots; many fine pores; extremely calcareous ;clear and smooth boundary. 95-135 cm: Very dark brown(10YR 2/2) when moist; clay texture ;strong medium and coarse sub angular blocky structure; friable when moist; very sticky & very plastic when wet; continuous prominent slickenside; weakly cemented nodular clay & carbonate, many white /black soft carbonate/manganese segregation ; few fine roots; common fine pores; extremely calcareous ;diffuse and smooth boundary. 135-200 cm: Very dark brown(10YR 2/2) when moist; clay texture; moderate medium angular blocky structure, friable when moist, very sticky & very plastic when wet; continuous prominent slickenside; weakly cemented nodular clay & carbonate; abundant white black soft carbonate segregation ; very few fine roots; common fine pores; extremely calcareous .clear and smooth boundary 200-230 cm: Black (10YR 2/1) when moist; clay texture; moderate medium angular blocky structure; friable when moist; very sticky & very plastic when wet; continuous prominent slickenside; many white soft carbonate segregation; common fine pores; extremely calcareous; clear and smooth boundary. 230-250 cm: Very dark brown (10YR 2/2) when moist; clay texture; weak fine and medium angular ‘blocky structure; friable when moist, sticky & plastic when wet; broken prominent slickenside; abundant white soft carbonate segregation; few fine pores; extremely calcareous; clear and smooth boundary. 250-290 cm: Very dark gray (10YR3/1) when moist; clay loam texture; common fine and medium gravel rock fragment; weak fine and medium angular blocky structure; friable when moist; sticky & plastic when wet; broken prominent slickenside; abundant white soft carbonate segregation & nodules; few fine pores; extremely calcareous. WWDSE In Association with ICT Final Feasibility Study Report 58Foderal Democratic Republic of Ethiopia- Ministry of Wator Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5- ANNEX 4 Soil Survey Study 10.2.3 Soil Mapping Unit Piso-ccVRcr-stC This mapping unit refers to Sodi-Calcic Vertisols, (Chromic), stony phase and developed on the foot slopes within the slope range between 2 and 4%, under cultivated land It is subjected to colluvial processes. The total extent of the unit is 88 ha (1.1%). The soils are very deep (>200 cm), imperfectly drained, very dark grayish (10 YR3/2) to very dark brown (10YR2/2) and the soil texture is clay through out the profile, which the clay content is 52.86 %. Clay increases with depth up to 76.35%. Consistencies are hard when dry, friable when moist and very sticky and very plastic when wet. Surface soils have moderate medium angular blocky structure, while subsurface soils have weak to moderate medium sub angular blocky structure. Common to many stones and boulders have been noted on surface. The cracks were developed to a depth of about 90 cm in all the studied profiles. Their widths at the soil surface ranged from 3 to 6 cm. Slickenside were observed and the paralleled structures were attributed to the soil texture, swelling, and shrinkage and pedoturbation in these soils. The infiltration rate is 7.8 cm/hr and it is marginally suitable. The hydraulic conductivity value is very slow (19 m/day) and the bulk density is 1.64 g/cm3. The AWC of these soils is high (200 mm/m). The pH value of the topsoil is 8.43, showing that the soil reaction is moderately alkaline. In sub soil the soil reaction increases and the soils reaction is strongly alkaline (pH=9.3). The soils have high organic carbon and its value is 3.59% and decreases downward the profile up to 1.69%. The content of total nitrogen on top soil is very high (0.36%) and decreases with depth. The proportion of organic carbon and total nitrogen is 10, showing it is good. The available phosphorus is very low (2.22 ppm) on surface soil and decreases with depth. The cation exchange capacity of topsoil is very high with value of 61.36 meq/100gm of soil on top soil and slightly decreases with depth (59.41 meq/100g soil). The average base saturation percentages of all soils are greater than 100% because of presence of high calcium carbonate. The soil is non saline with an average value of EC less than 0.2 mS/cm. The highest value of ESP up to depth of 100 cm is 34.72%, indicating that the soils are classified as sodic. Thus, these soils are required gypsum application. The value of CaCO3 is 24.80% and it may affect WWDSE In Association with ICT Final Feasibility Study Report 59Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and D etail Design of Bale Gadula Irrigation Project VOL 5- ANNEX 4 Soil Survey Study some sensitive crops such as potato, banana and citrus etc. The exchangeable sodium of the top profiles is 0.58 meq/100g soil and below surface soil it increases from 8.77 to 17.92 meq/100g soil. In this case the sodium might cause hazardous effect on soil property. In general the exchangeable of potassium is very high with value of 2.70 meq/100g soil on surface soil. However, it decreases under surface soil. The whole value of calcium of this unit is at very high level and its value is 53.76 meq/100 g soils on surface soil. Beneath surface soil the amount calcium is reducing up to 38.08 meq/100g soil. The Mg is at very high level (10.3 meq/100g soil) on top soil and it decreases with depth. The ratio of Ca: Mg is 5 decreases with depth as a result the availability of phosphorus and magnesium may be limited due to occurrence high calcium and pH value. The proportion of potassium to magnesium is 0.26 and it is favorable for vegetables crops. Model Soil Profile Description Profile code: BGP-06 Mapping unit: Piso-ccVRcr-stC Status: Sampled profile Date: 03AJ7/09 Soil classification, fao (2006): Sodi-Calcic Vertisols, (Chromic), stony phase Coordinates, Long (N): 0785774, Lat (E): 0653406, Elevation: 1925 Author: Atelbachew & Endalk Land form: Valley floor Relief intensity: <100 Map sheet No. 0740 C4 Regional slope: Flat to gently undulating Depth to bedrock: >200 cm Slope class: Very gently slope to gently Rock out crops: None Slope form: Uniform boulders Surface coarse fragments: Many stones and few Position: Low Micro topography: None Parent material: Alluvial deposits cultivated land Effective soil depth: Very deep grazing Drainage class: Well drained Drainage external: Well erosion Water table: None Flooding: None Surface cracks: Surface sealing: Fine to medium None Land cover: Open shrub land & intensively Land use: Rain fed arable cultivation & extensive Fertilizers: None Erosion status: Moderate rill & sheet 0-26 cm: Very dark brown (10YR 2/2) when moist; clay texture: moderate medium granular structure; firm when moist, very sticky & very plastic when wet; many fine to coarse roots; many fine to coarse pores; extremely calcareous; diffuse boundary. 26-98 cm: Very dark gray (10YR 3/1)when moist; clay texture; strong coarse prismatic structure; very firm when moist, very sticky & very plastic when wet; continuous prominent pressure face & slickenside; common white soft carbonate segregation ;common fine and medium roots; common fine and medium pores; extremely calcareous ;clear and smooth boundary. WWDSE In Association with ICT Final Feasibility Study Ro port 60Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Projoct VOL 5-ANNEX 4 Soil Survey Study 98-200 cm: Very dark grayish brown (10YR 3/2) when moist; clay texture ;very few coarse gravel rock fragment; strong medium sub angular blocky structure; firm when moist , very sticky & very plastic when wet ; broken prominent slickenside ; common white soft carbonate segregation ; few fine roots ; few fine pores ; extremely calcareous . 10.2.4 Soil Mapping Unit PiccVRpeC The mapping unit covers an area of 231 ha or about 3% of the project area. The soils of this unit are classified as Calcic Vertisols (Pellic), eroded phase, according to WRB, 2006. The soils developed from in situ weathered basaltic parent material and occur on piedmont plain with in slope gradient 2-4%. It has very deep effective soil depth (200 cm), with well to imperfect drained. Common stones and boulders on surface have been recorded It has been noticed common rill and gully features in this mapping unit. The color of the soils is very dark gray (10YR 3/1) over black (10YR2/1). The Land cover is open shrub land with moderately cultivated land. The soils have moderate and medium granular over moderate fine and medium sub angular blocky structure. Consistence is hard when dry, friable when moist and slightly sticky and slightly plastic when wet. The infiltration rate is 2.3 cm/hr. The hydraulic conductivity is 0.1 m/day. The soils are sandy clay textured on upper horizon. The clay content on surface soil is 38.38%. Under surface soil the clay content increases with depth. The sand silt fraction on surface soil is 48.45 and 13.16 respectively and they are decrease with depth. The bulk density is 1.78 g/cm3. The water holding capacity is 228 mm/m, indicating that it is very high level. The pH value on surface soils is 8.15 indicates that the soils are moderately alkaline. Beneath sub soil it increases with depth and reaches up to strongly alkaline (pH=9.03). The soils are non-saline with an average value of EC 0.15 mS/cm. The soils are slightly sodic with an average value of ESP is 3.08% with in 100 cm on top soil. The soils are calcic with maximum value of free carbonate on top soil up to depth is 23.11%. The soils have medium BS% with 56%. The CEC is very high with value of 60.43 meq/100g soil on upper horizon. Under surface soils its distribution is irregular The organic carbon is very high with value of 2.99% on surface soil and decreases with depth. The value of total nitrogen on top soil 0.293%, depicting that it is at high status. Beneath surface soil it decreases WWDSE In Association with ICT Final Feasibility Study Report 61Fedoral Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study (0.02%). The ratio of organic carbon to nitrogen is 10. The available phosphorus on surface soil is 3.22 ppm, indicating that it is at very low level and increases below surface soil it is also categorized to high class (6.25 ppm). These soils have low exchangeable sodium 0.25 meq/100 g soils on surface soil and increases with depth up to 1.67 meq/100g soil. Thus, it might have an adverse effect on soil property. The exchangeable potassium is at high level 0.86 meq/100g soil on top soil. Under surface soil is also it is high (0.89 meq/100g soil). These soils have very high level calcium content with value of 51.98 meq/100g soil on top soil. Under surface increased to B horizon and its content is 52.48 meq/100 g soils. The soil have very high magnesium level with value of 19.44 meq/100g soils and increased at B horizons (20.79 meq/100g soil.) The ratio of Ca: Mg is 3 and it is showing that it is an optimum range. The proportion of potassium to magnesium is 0.04 and it is favorable for vegetables crops. Model Soil Profile Description Profile code: BGP-16 Mapping unit: PiccVRpeC Status: Sampled profile Date: 27/06/09 Soil classification, FAO (2006): Calcic Vertisols Coordinates, Long (N): 0787561 Author: Land form: Relief intensity: Regional slope: Slope class: Slope form: Position: Micro topography: Parent material: Addisu & F/Mariam Lat (E): Valley floor <100 Elevation: Level Concave Low Level Alluvial 0651412 None 1931 Map sheet No. 0740 C4 Flat to gently undulating Depth to bedrock: >200 cm Rock out crops: Effective soil depth: Very deep Drainage class: Moderate well drained Drainage external: Slow Surface coarse fragments: Common stones Surface cracks: None Surface sealing: None Land cover: Open shrub land & intensively cultivated land Land use: Rain fed arable cultivation & Extensive grazing Fertilizers: None Erosion status: Common rill & gully Water table: None Flooding: None 0-25 cm: Very dark gray (10YR 3/1) when moist; clay loam texture; weak fine and medium granular structure; very friable when moist, sticky & plastic when wet; patchy faint clay cutans; abundant fine and medium roots, abundant fine and medium pores; extremely calcareous jclear and smooth boundary. 25-75 cm: Black (10YR2/1) when moist; clay texture; moderate medium angular blocky structure; friable when moist, very sticky & very plastic when wet; broken distinct slickenside cutans; common white/ black both hard and soft carbonate/manganese segregation /nodules; many fine and medium roots; many fine and medium pores; extremely calcareous. 75-180 cm: Very dark grayish brown (10 YR3/2)when moist; clay texture; strong medium and coarse angular blocky structure; firm when moist, very sticky & very plastic when wet, continuous prominent slickenside; many white soft carbonate segregation ; lm- —as— WWDSE In Association with ICT Final Feasibility Study Report 62Federal Democratic Republic of Ethiopia Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5- ANNEX 4 Soil Survey Study common fine roots; many fine pores; extremely calcareous . 180-200 cm: Very pale brown (10 YR 8/2 )when moist; clay loam texture; weak structure; firm when moist, sticky & plastic when wet; moderately cemented nodular carbonates; abundant white soft carbonate segregation ; few fine roots; common fine pores; extremely calcareous . 10.2.5 Soil Mapping Unit VB1ccVRwn-crA These soils of this unit are Calcic Vertisols (Hyposodic, Chromic). They are somewhat imperfect drained. These soils occur on very gentle slope (0-1% slope) and have developed on alluvial deposits. This unit is the one of most extensive and its extent is 607 ha (7.9%). They are very deep, sandy clay loam over clay textured, black (10YR 2/1) over very dark brown (10YR 2/2) in color. The clay content on surface soil is 33.34% and it increases with depth up to 70.51% at the bottom of the profile. While the sand and silt fraction is 53.76 and 12.90% respectively and their values reduced with depth. The Land cover is moderately cultivated land with scattered trees. The land is used for rain fed arable cultivation. Common stones and boulders have been noted on surface. The soil has weak fine granular over moderately develop sub-angular blocky-structure. The consistence of the soil is hard when dry, friable during moisture condition and slightly sticky and slightly plastic. The infiltration rate is 2.3 cm/hr and it is suitable for surface irrigation. The hydraulic conductivity is 0.1 m/day and it is slow. The bulk density is 1.58 g/cm . The available soil moisture of the soils is 139 mm/m. The soil reaction is moderately alkaline with pH value of 8.38 on surface soil. Under surface soil the pH increases with depth up to 9.1. The soils are calcic with value of 15.48%. The soils in this unit are non saline with EC value of 0.8 mS/cm. The soils are sodic with value of 11.54%. The soils have very high CEC level with value of 75.83 meq/100g soil on surface soil. However, in sub soil its content decreased slightly from 73.85 to 64.36 meq/100g soil. The content of organic carbon is very high with value of 2.57% on top soil. As usual it decreases down the profile up to 1.29%. The value of total nitrogen on top soil is 0.277% and with depth decreases, the result of the analysis depicting that the total nitrogen is high. The ratio of organic carbon to nitrogen is 9, indicating that the quality of organic matter is good. The available phosphorous is at medium level on surface soil and beneath surface soil it decreases. These soils have high level exchangeable 3 WWDSE In Association with ICT Final Feasibility Study Report 63Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study sodium on top and increased to C horizons. The exchangeable potassium is very high on surface soil (1.25 meq/100g soil) and decreased with depth (0.64 meq/100g soil. These soils have very high calcium content (59.28 meq/100g soil) on top horizon. Meanwhile in substratum it decreased to C horizon (39.32 meq/100g soil) The soils have very high magnesium level 12.74 meq/100g soils and increased to Ck horizons. The ratio of Ca: Mg is 5 and it may adversely affect the availability of phosphorus and magnesium due to high concentration of calcium. The proportion of potassium to magnesium is 0.1 and it is favorable for vegetables. Model Soil Profile Description Profile code: BGP-14 Date: 01/07/09 Mapping unit: VBlccVRwn-crA Status:S«mpted profile Soil classification, fao (2006): Calcic Vertisols (Hyposodic, Chromic) Coordinates, Long (N): 0783013, Lat {E):0657406 Elevation: 1868 Author: Land form: Relief intensity: Regional slope: Slope class: Slope form: Atelbachew & Eyouale Valley floor <100 Flat Level Uniform Medium Level Alluvial deposits Map sheet No. Depth to bedrock: Rock out crops: 0740 C4 >200 cm None Surface coarse fragments: common stones & coarse grave/ Position: Micro topography: Parent material: land Effective soil depth: Very deep cultivation Drainage class: Drainage external: erosion Water table: Flooding: We// drained Slow None Biennially 1-15 days Surface cracks: Surface sealing: Land cover: Land use: Fertilizers: Erosion status: None None Intensively cultivated Rain fed arable None Slight sheet and splash 0-30 cm: Black (10YR 2/1) when moist; , clay texture; weak mgedium sub angular blocky 30-108 cm: 108-200 cm: structure; friable to firm when moist, very sticky & very plastic when wet; common fine and medium roots; common fine and medium pores; strongly calcareous; diffuse boundary. Very dark brown (10YR2/2 )when moist; clay texture; strong coarse platy structure, firm when moist, very sticky & very plastic when wet; continuous prominent pressure face cutans; few fine root; few fine pores; strongly calcareous .clear and smooth boundary. Dark brown (10 YR3/3 )when moist; few yellowish brown mottle ;day texture: strong medium sub angular blocky structure; firm when moist, very sticky & very plastic when wet; broken distinct slickenside cutans; few white soft carbonate segregation ; few fine roots; very few fine pores; strongly calcareous . WWDSE In Association with ICT Final Feasibility Study Report 64Federal Democratic Ropublic of Ethiopia- Ministry of Wator Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5- ANNEX 4 Soil Survey Study 10.2.6 Soil Mapping Unit VB2haVRca-huC This mapping unit covers an area of 206 ha or 2.7% of the project area. The soils of this unit are classified as Haplic Vertisols (calcaric, Humic) stony phase, according to WRB, 2006. This mapping unit is developed on old alluvial material over laying in situ weathered parent material on almost flat to flat landform (1-2%). The Land cover is open open grass land with cultivated land. The land use is arable rainfed cultivation with extensive grazing and browsing. It is prone to slight sheet and rill erosion. The soils are very deep (156-200 cm), imperfectly drained, with common surface coarse fragments. The soil is dark gray (10YR 4/1) over very dark gray (10YR 3/1) in color, with weak medium granular over strongly developed medium and coarse sub angular blocky structure, clay loam over sandy clay loam in texture. The clay content is 39 86% on top soil and the content of sand and silt is 34.28% and 25.86% respectively on surface soil. While the silt content reduced up to 20.69%, the sand fraction increased to B horizon and the clay content increases (49.00%).Average infiltration rate is 2.3 cm/hr. The average hydraulic conductivity is 0.1 m/day. The bulk density is 1.3 g/cm3 on top soil and increased to B horizons up to 1.76 g/cm . The available moisture is 200 mm/m. The soils reaction of this mapping unit is slightly alkaline with pH value is 7.11 on top soil. In sub soil it increased with depth and the soils are moderately alkaline. The CaCO3 content up to depth of 100 cm is 13.13%. The soils have very high organic carbon with value of 3.98% on top soil and decreased with depth. The total nitrogen is at very high level on upper soil with value of 0.38% and decreased downward the profile. The proportion of organic carbon to nitrogen is 11. This mapping unit has very low available phosphorus on surface soil (1.75 ppm) and decreased with depth. The sol is non sodic and non saline. The exchangeable sodium on top soil is 0.14 meq/100g soil and in sub soil it decreases. Thus, in both cases Na is at minimum level and there will not be any adverse effect on soil property. The soils have very high exchangeable potassium on surface is 3.10 meq/100g soil and decreased with depth. On surface the exchangeable calcium is very high with value of 43.46 meq/100g soil. In sub soil it increased to Bk horizon up to 49.73 meq/100g soil. These soils have very high magnesium on surface soil (7.62 meq/100g soil) and in sub soil it increased to Bk horizons. The 3 WWDSE In Association with ICT Final Feasibility Study Report 65Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study proportion of calcium to magnesium is 6, indicating that the availability of magnesium and phosphorus is limited due to the presence of calcium content The proportion of K: Mg is 0.41, showing that it is at recommended level for vegetables. The cation exchange capacity is very high with value of 69.63 meq/100g soil on top soil and under top soil it decreased with depth. The soils have vey high BS% with average value of 78%. Model Soil Profile Description Profile code: BGP-11 Date: 04/07/09 Mapping unit: VB2haVRca-huC Status: Sampled profile Soil classification, fao (2006): Calcic Vertisols (Humic, Pellic) Coordinates, Long (N): 0784949 Lat (E): 0656397 Elevation: 1891 Author: Land form: Atelbachew & Eyouale Plain Relief intensity: <100 Regional slope: Flat Map sheet No. 0740 C4 Slope class: Very gently slope Slope form: Convex Position: Medium Depth to bedrock: 156 cm Rock out crops: Common Surface coarse fragments: Common stones Surface cracks: Medium Micro topography: None Parent material: Alluvial deposits over in situ cultivated land Effective soil depth: Very deep Surface sealing: None Land cover: Bush shrub grass land & intensrvety Land use: Rain fed arable cultivation & extensive grazing Drainage class: Well drained Drainage external: Well erosion Water table: None Flooding: None Fertilizers: Erosion status: None Slight sheet and splash 0-17 cm Dark gray (10YR 4/1) when moist; clay texture; weak fine and medium granular structure; firm when moist; sticky & plastic when wet, common fine and medium roots; common fine and medium pores; slightly calcareous; diffuse boundary. 17-82 cm: Very dark gray (10YR3/1) when moist; clay texture; strong coarse sub angular blocky structure; firm when moist, very sticky & very plastic when wet; broken distinct slickenside cutans; few white both soft and hard carbonate segregation ; common fine roots jeommon fine pores; strongly calcareous .clear and smooth boundary. 82-156 cm: Very dark brown(7.5 YR 2.5/2 ) when moist; clay texture; weak medium granular structure; firm when moist, very sticky & very plastic when wet; patchy faint shiny faces cutans; abundant white both hard and soft carbonate segregation & nodules ; few fine roots; few fine pores; extremely calcareous . WWDSE In Association with ICT Final Feasibility Study Report 66Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study 10.2.7 Soil Mapping Unit VB2moVRca-peB These soils of this unit are Mollie Vertisols (Calcaric, Pellic). They are somewhat imperfectly drained. These soils occur on very gentle slope (1-2% slope) and have developed on colluvial/alluvial deposits. This unit is the one of less extensive and its extent is 857 ha (11.57%). They are very deep (200cm) and very dark gray (10YR 3/1) over very dark brown (10YRR 2/2) in colour Few to common stones and gravels have been noted on soil surface. This mapping unit is slightly affected sheet erosion. The Land cover is intensively cultivated land and this land unit is used or rain fed agriculture and grazing domestic animals. The soil has moderately fine and medium granular on surface soil and strongly develop medium to coarse columnar and sub-angular blocky-structure. The soils of this unit have broken distinct slickenside in subsurface soil. The infiltration rate is 2.3 cm/hr, indicating that it is in optimum range for surface irrigation. The hydraulic conductivity is 0.1 m/day, showing that it is slow. The textural classes of these soils are clay through out The clay content on surface soil is 65.08% and decreased with depth. While the fraction of sand silt on top soil is 23.19 and 11.74% respectively and their values decreases with depth. The bulk density is 1.48 g/cm3 on surface soils and increased to 1.68 g/cm . 3 The available moisture content of this soil mapping unit is 200 mm/m. The pH value on surface soils is 7.74, which indicates that the soils are slightly alkaline. Beneath surface soil the soil reaction is strongly alkaline (pH=8.16). The soils are non-saline with an average value of EC 0.33 mS/cm. The soil is slightly sodic with value of 6.31% on top soil. The soil is calcareous with value of 9.54%. The soils have very high CEC with value of 81.32 meq/100g soil on surface soil In sub soils it decreased. The soils also have very high BS% (99%).The value of organic carbon is 1.56%, indicating that it is moderately high on surface soil. While under surface it decreases. The value of total nitrogen on top soil is 0.08%, depicting that it is at very low status. Beneath surface soil it decreases. The ratio of organic carbon to nitrogen is 20, indicating that the quality of organic matter is poor. The available phosphorus on surface soil is 4.16 ppm, indicating that it is falling in to low level. Below surface soil it reduces to low value. These soils have high to very high level exchangeable sodium with value of 1.44 meq/100g soil on WWDSE In Association with ICT Final Feasibility Study Report 67Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study surface soil. Below surface soil its content is increased to Ck horizon up to 7.83 meq/100 g soils. Thus, it might affect the soil property. The exchangeable potassium is 0.73 meq/100g soil on top soil, which shows that it is at high level. Under surface soil it decreases. These soils have very high calcium content on top soil (54 66 meq/100g soil) and under surface soil it increases. The soils have very high magnesium with value of 23.3 meq/100g soils on top soil and in sub-soil it decreases. The ratio of Cam is 2.35 and it may prohibited the availability of phosphorus. The proportion of potassium to magnesium is 0.03 and it is favorable for vegetables crops. Model Soil Profile Description Profile code: BGP-12 Mapping unit: VB2moVRca-peB Status:Sainpled profile Date: 12/07/09 Soil classification, FAO (2006): Mollie Vertisols (Calcaric, Pellic) Coordinates, Long (N): 0785030 Author: Atelbachew & Eyouale Land form: Valley floor Lat (E): 0657442 Elevation: 1897 Relief intensity: Regional slope: Slope class: Slope form: <100 Flat to gently undulating Very gently slope Map sheet No. Depth to bedrock: Rock out crops: 0740 C4 >200 cm None Position: Uniform High Surface coarse fragments: Few stones and gravel Surface cracks: Medium Micro topography: Level Parent material: Colluvial deposits over Effective soil depth: Very deep Drainage class: Well drained Drainage external: Well Water table: None Flooding: None Surface sealing: None Land cover: Intensively cultivated land Land use: Rain fed arable cultivation Fertilizers: None Erosion status: Slight sheet and splash erosion 0-27 cm: Very dark gray (10YR 3/1) when moist; clay texture; moderate medium sub angular blocky structure; friable to firm when moist, very sticky & very plastic when wet; patchy faint slickenside ; common fine and medium roots; common fine and medium pores; slightly calcareous ;diffuse boundary. 27-135 cm: Very dark brown (10YR 2/2) when moist; clay texture; moderate coarse sub angular blocky & angular blocky structure; friable to firm when moist, very sticky & very plastic when wet; continuous prominent slickenside; few white soft carbonate segregation ; common fine roots; common fine pores; strongly calcareous ; clear and smooth boundary. 135-200 cm: Black (10YR2/1) when moist; clay texture; strong medium angular blocky structure; friable to firm when moist; very sticky & very plastic when wet; continuous prominent slickenside; common white soft carbonate segregation; strongly calcareous. VWVDSE In Association with ICT Final Feasibility Study Report 68Federal Democratic Republic of Ethiopia- Ministry of Water Resources feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study 10.2.8 Soil Mapping Unit VB1ccVRpe-stA The mapping unit covers an area of 584 ha or 7.6% of the project area. The soils of this unit are classified as Calcic Vertisols (Pellic), according to WRB, 2006 This mapping unit is developed on old alluvial material over laying in situ weathered parent material on almost flat to flat (0-1%) topography. The Land cover is open wood land and with scattered cultivated land. The land use is rain fed cultivation with extensive grazing. The area is prone to sheet and rill erosion. The soils are very deep (160 cm), somewhat imperfectly drained. The colour of the soils are dark gray (10YR 4/1) over dark brown (10YR3/3) in color, with moderate medium granular over strongly developed medium to coarse sub-angular blocky-structure. The texture of the soil is clay throughout the profile. The clay content of surface soil is 48.48% and increases with depth. The soils of this unit have few to common stones and boulders on surface and distinct slickenside on preface in subsurface soil. The infiltration rate is 7.8 cm/hr, which is marginally suitable for surface irrigation The hydraulic conductivity is 0.19 m/day, it is very slow. The bulk density is 1.49 g/cm3 on upper surface and increased up to 1.94 g/cm3 at Ck horizon. As a consequence in sub soils there would be a compaction problem. The available moisture content is 215 mm/m, showing that it is at very high level. The soil reaction is slightly acidic and the pH value is 6.95 and increases with depth. Below surface soil the soil reaction is moderately to strongly alkaline. The soils are non-saline with an average value of EC 0.11 mS/cm and non-sodic (ESP=1.24%). The value of CaCO3 is 15.93 on top 100 cm depth. The CEC value of this mapping unit is very high, its value on top soil is 45.69 meq/100 g soils and in subsoil its content does not have significant variation with depth. The soils have very high BS% with value of 87% on surface soils and decreases with depth. The exchangeable sodium is low on top soil (0.22 meq/100 g soils) and it is low to medium in sub soil varying from 0.29 to 0.52 meq/100g soil. As far as it is less than 1 meq/100g soil it may not cause any negative effect on soil property. The given mapping unit has high exchangeable potassium and its value is 1.22 meq/100 g soils. However, it is increases to Bk horizons (2.61 meq/100g soil. The content of calcium is at very high level with top-soil value of 22.15 meq/100g soil. The magnesium is also very high (16.27 meq/100g soil) on surface soil. There is WWDSE In Association with ICT Final Feasibility Study Report 69Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5- ANNEX 4 Soil Survey Study no considerable variation in its content between surface and subsoil and increased to Ck horizon The organic carbon content is 2.6%, indicating that its status is very high. As usual it decreased beneath surface soil. The total nitrogen is high with value of 0.28 %. But decreases below surface soil up to 0.08%. The organic carbon to total nitrogen ratio is 9 On surface soil the available phosphorus is 4.3 ppm, showing that there is deficiency phosphorus and there is necessity of application fertilizers. The ratio of calcium to magnesium is 1.7. Thus, the uptake phosphorus may be inhibited. The proportion of potassium to magnesium is 0.07, indicating that it is conducive for vegetables cultivation. Model Soil Profile Description Profile code: BGP-18 Mapping unit: VBIccVRpeA Status: Sampled profile Date: 02/07/09 Soil classification, FAO (2006): Calcic Vertisols (Pellic) Coordinates, Long (N): 0781946 Author: Atelbachew & Eyouale Lat (E): 0658577 Land form: Valley floor Elevation: 1864 Relief intensity: <100 Map sheet No. 0740 C4 Regional slope: Flat Depth to bedrock: 160 cm Slope class: Nearly level Rock out crops: Few Slope form: Uniform boulders Position: Medium Surface cracks: Medium Micro topography: Animal tracks Surface sealing: None lanri Parent material: Alluvial deposits over in situ Effective soil depth: Very deep Surface coarse fragments: common stones & large Land cover: Intensivety cultivated land, busbed shrub grass Land use: Rain fed arable cultivation & extensive grazing Drainage class: We// drained Drainage external: We// erosion Water table: None Flooding: None Fertilizers: None Erosion status: Slight sheet and splash 0-26 cm: Dark gray (10YR 4/1) when moist; clay texture; weak medium sub angular blocky structure; firm when moist, very sticky & very plastic when wet; many coarse roots; many coarse pores; strongly calcareous; diffuse boundary. 26-77 cm: Dark brown (10YR 3/3) when moist; clay texture; strong coarse angular blocky structure; very firm when moist, very sticky & very plastic when wet, broken distinct slickenside cutans; common fine and medium roots; few fine pores; strongly calcareous; clear and smooth boundary. 77-160 cm: Very dark grayish brown (10 YR 3/2) when moist; clay texture; strong coarse sub angular blocky structure; very firm when moist, sticky & plastic when wet; continuous prominent slickenside cutans; common white both hard and soft carbonate segregation & nodules; few fine and medium roots; few fine pores; extremely calcareous. WWDSE In Association with ICT Final Feasibility Study Report 70Federal Democratic Republic of Ethiopia- Ministry of Water Resources ^£3slbiiityStudy and Detail Design of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study 10.2.9 Soil Mapping Unit VB1so-ccVRhu-pe-stA The Soil mapping unit VB1so-ccVRhu-peA, stony phase is covering an area of 512 ha or about 6.6% of the project area. The soils of this unit are classified as Sodi-Calcic Vertisols, (Humic, Pellic) according to WRB, 2006. The soils in this unit are very deep (200 cm), somewhat imperfectly drained, very dark gray (10YR3/3) over black (10YR2/1) colored and clay textured. Its clay content on surface soil is 52.82% and it increases with depth. The sand and silt fraction is 27.77 and 19.4% respectively on surface soil and decreased with depth. Land cover is open shrub land. The present land use is mainly grazing and browsing by cattle and goats. The unit is slightly affected by rill and gully erosion. Common surface stones and boulders have been detected. The soils have weak medium blocky over moderately develop sub-angular blocky-structure. The infiltration rate is 1 cm/hr, which is with in optimum level. The hydraulic conductivity is 0.11 m/day and very slow. The bulk density is 1.71 g/cm3 on surface soil and decreases with depth. The available soil moisture is high with value of 200 mm/m. The soils are clacic with the maximum value of CaCO3 with in 100 cm depth is 23.79%.The soils in this unit are nor^ saline. The ESP value with in depth of 100 cm is 21.72%, indicating that the soils are sodic. Thus, these soils are required gypsum application. The value CEC is very high with value of 74.02 meq/100 g soils on surface soil. Under surface soil it decreases. The base saturation percentage id exceeding 100% because of high occurrence of CaCO .The 3 content of organic carbon and total nitrogen is very high with value of 3.35% and 0.31% respectively and their values decreases with depth. The proportion of organic carbon to total nitrogen is 11. The available phosphorous is very low (3.5 ppm) on surface soil and decreases with depth. The pH value is 7.8 on upper surface, indicating that the soil reaction is slightly alkaline. These soils have high level exchangeable sodium (1.66 meq/100g soil) on top soil and increases paramount up to 19.48 meq/100g soil. The exchangeable potassium is at medium level (0.47 meq/100g soil). These soils have very high calcium (69.44 meq/100g soil and decreases mildly with depth. The magnesium level is very high 13.44 meq/100g soils and increased to B horizon. The ratio of Ca: Mg is 5, indicating that the WWDSE In Association with ICT Final Feasibility Study Report 71Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study deficiency of phosphorus and magnesium will be occurred. The proportion of potassium to magnesium is 0.03 and it is favorable for vegetables crops Model SOIL PROFILE DESCRIPTION Profile code: BGP-40 Mapping unit: VB1so-caVRhu-peA Status: Sampled profile Date: 09/07/09 Soil classification, FAO (2006): Sodi-Calcic Vertisols (Humic, Pellic) Coordinates, Long (N): 0781998 Author: Kinfe & Eliays Land form: Valley floor Relief intensity: <100 Regional slope: Flat to gently undulating Slope class: Nearly level to very gently Lat (E): Elevation: Map sheet No. Depth to bedrock: Rock out crops: 0668399 1736 0740 D3 >200 cm None Slope form: Uniform to Concave Position: Low Micro topography: Animal tracks Parent material: Alluvial deposits land Effective soil depth: Very deep grazing Drainage class: Moderate well drained Drainage external: Well erosion Water table: None Flooding: None Surface coarse fragments: Very few stones Surface cracks: Fine to medium Surface sealing: None Land cover: Moderately cultivated land, open shrub & bush Land use: Rain fed arable cultivation & Extensive Fertilizers: Erosion status: DAP 100 kg/ha Moderate nil & gully 0-20 cm. Very dark gray (10 YR 3/1) when moist; clay texture; strong fine and medium granular structure; firm when moist, very sticky & very plastic when wet; patchy faint clay cutans; common white both hard and soft carbonate segregation & nodules ; many fine and medium roots; many fine and medium pores; extremely calcareous ;diffused boundary. 20-80 cm: Black (10 YR 2/1)when moist; clay texture; strong medium and coarse angular blocky structure; very firm when moist, very sticky & very plastic when wet; broken distinct slickenside cutans; common white soft carbonates segregation ; many fine roots; many fine pores; extremely calcareous .diffused boundary. 80-115 cm: Very dark grayish brown (10 YR 3/2 )when moist; clay texture; strong medium and coarse angular blocky structure; very firm when moist, very sticky & very plastic when wet; broken distinct slickenside cutans; many white soft carbonates segregation nodules; common very fine roots; many fine pores; extremely calcareous; clear boundary. 115-200 cm: Very dark gray (10 YR 3/1)when moist; day texture; strong medium and coarse angular blocky structure; firm when moist, very sticky & very plastic when wet: continuous distinct slickenside cutans; many white both soft and hard carbonates segregation & nodules; common very fine roots; many fine pores; extremely calcareous carbonate. WWDSE In Association with ICT Final Feasibility Study Report 72Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study 10.2.10 Soil Mapping Unit VB2haNThu-stB The mapping unit covers an area of 718 ha or about 9.3%of the project area .The soils of this unit are classified as Haplic Nitisolsols (Humic) stony phase according to WRB, 2006 This mapping unit is developed on old alluvial material over laying in situ weathered parent material on very genteel undulating (1-2%) topography. The Land cover is open grass land with moderately cultivated land. The land use is arable rainfed cultivation with pastoral grazing and browsing. The area is prone to sheet and rill erosion. On soil surface have been recorded common stones and boulders. The soils are very deep (200 cm), well-drained. The colour of the soils are sandy clay over clay over dusky red (2.5YR3/2) in color, with weak medium granular over strongly developed medium to coarse sub-angular blocky-structure. The texture of the soil is sandy clay over clay. The clay content of surface soil is 40.29% and increased considerably with depth. The sand and silt fraction is 48.82 and 10.89% on top soil. In sub soil the sand content decreased whie silt increased. The soils of this unit have few to common distinct shiny pedface in subsurface soil. The infiltration rate is 2.3 cm/hr. The hydraulic conductivity is 0.1 m/day. The bulk density is 1.4 g/cm3 The soils have high water holding capacity with value of 317 mm/m. The soil reaction is moderately alkaline with pH value of 7.52. Through out the profile the pH values have no significant variation from one to another horizon. The soils are calcareous with value of 3.59%. The soils are non-saline with an average value of EC 0.06 mS/cm. The value of ESP is 1.07%. The CEC value of this mapping unit is very high with value of 71.0 meq/100g soils on top soil and decreases with depth. The soils have very high BS% with value of 119% on surface soil and decreased to B horizons. The exchangeable sodium is high on top soil (0.76 meq/100 g soils) and decreased to 0.25 in B horizons. As far as it is less than 1 meq/100g soil it may not cause any negative effect on soil property. This mapping unit has high exchangeable potassium and its value is 0.94 meq/100g soil. However, it is decreasing beneath top-soil. The content of calcium is at very high level with value of 67.2 meq/100g soil top-soil and reduced. The magnesium is very high (15.68 meq/100g soil) on surface soil and decreased to C horizon. The ratio of calcium to magnesium is 4.29, showing that it is optimum WWDSE In Association with ICT Final Feasibility Study Report 73Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Dotail Design of Bale Gadula Irrigation Project VOL 5- ANNEX 4 Soil Surrey Study range for most crops. The proportion of potassium to magnesium is 0.2, indicating that it is conducive for vegetables cultivation. The soils have very high organic carbon with value of 6.97% on upper horizon and decreased with depth. The total nitrogen is very high with value 0.63 % and decreases below surface soil up to 0.113%. The organic carbon to total nitrogen ratio is 11. On surface soil the available phosphorus is medium with value of 5.51 ppm and increased to B horizons. Model Soil Profile Description Profile code. BGP-22 Mapping unit: VB2haNThu-stB Status: Sampled profile Date: 2&06/09 Soil classification, FAO (2006): Coordinates, Long (N): 0782234 Author: Addisu Haplic Nitisolsols (Humic) stony phase; Lat(E): 0660428 Elevation: 1853 Land form: Valley floor Relief intensity: <100 Regional slope: Gently undulated Slope class: Gently slope Slope form: Convex Position: Lowest Micro topography: Level Parent material: Alluvial deposits Effective soil depth: Very deep Map sheet No. 0740 C4 Depth to bedrock: >200 cm Rock out crops: None Surface coarse fragments: Common srones i ixxJders Surface cracks: None Surface sealing: weak Land COVer: Busn ihnjb land. precoftunaniry cuevafrd land Land use: Ram fed arable cultivation i Extensive grazing Drainage class: Moderate well drained Fertilizers: Drainage external: Well Water table: None Flooding: None Erosion status: None — None 0-20 cm: Dark reddish brown (2.5YR 2.5/3) when moist; day loam texture, weak medium granular structure; friable when moist, sticky & plastic when wet; abundant fine and medium roots, abundant fine and medium pores, strongly calcareous; dear and smooth boundary. 20-70 cm: Dusky red (2.5YR 3/2) when moist, day texture, moderate medium sub angular blocky & angular blocky structure, firm when moist, very sticky & very piastre when wet; continuous prominent slickenside; many fine and medium roots, many fine pores; strongly calcareous; dear and smooth boundary. 70-150 cm: Dark reddish brown (2.5YR 3/3)when moist; clay texture; strong medium & coarse angular blocky structure; firm when moist, very sticky & very plastic when wet. continuous prominent slickenside; moderately cemented nodular day & carbonate; common white both hard and soft carbonate segregation ; common fine roots, common fine pores, extremely calcareous ; clear and smooth boundary. 150-200: Dusky red (2.5YR 3/2) when moist; clay texture; many fine and medium rock fragment; strong medium to coarse angular blocky structure, firm when moist, very sticky & very plastic when wet; continuous prominent slickenside; moderately cemented nodular day & carbonate; many white both hard and soft carbonate segregation & nodules; very few fine roots; common fine pores; extremely calcareous. WW0SE In Association with ICT Final Feasibility Shxfy Report 74Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Doslgn of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study 10.2.11 Soil Mapping Unit VB2ccVRwn-peB The mapping unit covers an area of 445 ha or about 5.8% of the project area. The soils of this unit are classified as Calcic Vertisols, (Hposodic, Pellic) according to WRB, 2006. The soils in this unit developed from in situ weathered basaltic parent material on gently sloppy land with slope gradient of 1-2%. The soils in this unit are clay textured through out the profile. The clay content on surface soil is 46.38%. Under surface soil the clay content increased down ward the profile, varying from 70.78 to 74.34%. It is very deep (200 cm) with imperfectly drained and few and no surface coarse fragment. The colour of the soils is very dark gray (10YR 3/1) over very dark brown (10YR 2/2). The Land cover is cultivated land and used for rainfed cultivation. The soils have moderately developed fine to medium granular structure on soil surface and while under soil surface strongly developed angular blocky-structure. The soils of this unit have distinct slickenside in subsurface soil. The consistence of the soils is friable when moist and very sticky and very plastic. The infiltration rate is at optimum level with value of1.1 cm/hr. The hydraulic conductivity is very slow with value of 0.04 m/day. The bulk density is 1.40 g/cm3 on surface soil and increased to C horizon up to depth of 1.78 g/cm The available soil moisture is high (200 mm/m). The pH value on surface soils is 7.62, which indicates that the soils are slightly alkaline. Beneath sub soil it is varying from moderately alkaline (pH=8.23).The soils are non-saline with an average value of EC 0.36 mS/cm. The soil is moderately sodic with maximum value of on top soil up to the depth of 100 cm 14.15%. The soils are calcareous with value of 23.67% on top soil up to the depth of 100cm. The CEC is very high 48.70 meq/100g soil on surface soil. The value of BS% is exceeding 100% throughout the profile due to presence of high calcium carbonate. The soils have very high value of organic carbon (3.31%). While under surface it decreases. The value of total nitrogen on top soil is 0.37%, depicting that it is at very high status. Beneath surface soil it decreases. The ratio of organic carbon to nitrogen is 9, indicating that the quality of organic matter is good. The available phosphorus on surface soil is very low with value of 3.76 ppm. Below surface soil it is reduced. These soils have medium level exchangeable sodium, 0.53 meq/100g soil on surface soil. Beneath surface soil it increases to B horizon 3 WWDSE In Association with ICT Final Feasibility Study Report 75Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Balo Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study up to 8.47 meq/100 g soils. Thus, it might not have any adverse effect on fertility status. The exchangeable potassium is 0.94 meq/100g soil on top soil, which showing that potassium is at high level. Under surface soil it is reduces. These soils have very high calcium content on top soil (48.83 meq/100g soil) and in sub soil it decreases. The magnesium level is very high through out the profile. The ratio of Ca: Mg is 5 and it may prohibit the availability of magnesium and phosphorus. The proportion of potassium to magnesium is 0.10 and it is favorable for vegetables crops. Model Soil Profile Description Profile code: BGP-46 Mapping unit: VB2ccVRwn-peB Status: Sampled profile Date: 17/07/09 Soil classification, fao (2006): Calcic Vertisols, (Hposodic, Pellic) Coordinates, Long (N): 0780958 Lat (E.y.0672428 Elevation: 1670 Author: - kinfe & Tilahun Land form: Valley floor Relief intensity: <100 Regional slope: Flat Map sheet No. 0740 D3 Slope class: Very gently slope Slope form: Uniform Depth to bedrock: 200 cm Rock out crops: None Surface coarse fragments: Few stones Position: Low Surface cracks: Fine Micro topography: Level Surface sealing: weak Parent material: land' Alluvial deposits Land cover: Intensively, cultivated Effective soil depth: Very deep cultivation Drainage class: Moderate well drained Drainage external: Slow Water table: None Land use: Rain fed arable Fertilizers: None Erosion status: Slight water and wind erosion Flooding: None 0-30 cm: Very dark gray (10 YR 3/1) when moist; clay texture; strong medium and coarse granular structure; very firm when moist, very sticky & very plastic when wet; many medium and coarse roots; few termite or ant channel and nests; many medium and coarse pores; extremely calcareous; diffuse boundary. 30-110 cm: Very dark brown (10YR 2/2) when moist; clay texture; strong medium and coarse angular blocky structure; very firm when moist, very sticky & very plastic when wet; broken distinct slickenside; few white both hard and soft carbonate segregation & nodules; common fine and medium roots; few termite or ant channel & nests; many fine and medium pores; extremely calcareous; clear and smooth boundary. 110-200 cm: Dark brown (10 YR 3/3) when moist; clay texture; strong medium and coarse angular blocky structure; very firm when moist, very sticky & very plastic when wet; broken distinct slickenside; common white/ black both hard and soft carbonate /manganese segregation & nodules; few very fine roots; many fine and medium pores; extremely calcareous. WWDSE in Association with ICT Final Feasibility Study Report 76Fodcral Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study 10.2.12 Soil Mapping Unit VB1moVRca-wnA The mapping unit covers an area of 468 ha or about 6.1% of the project area. The soils of this unit are classified as Mollie Vertisols (Calric, Hyposodic) according to WRB, 2006.The soils in developed from in situ weathered basaltic parent material on g with slope gradient of 0-1%. The textural classes of these soils are clay through out the profile. The clay content on surface soil is 48.75%. In 'B’ horizon the clay content is higher than surface soil and its value is 72.68%. It is very deep (200 cm) with some what imperfectly drained and few and no surface coarse fragment. This mapping unit is slightly affected by sheet erosion. The colour of the soils is very dark grayish brown (10YR 3/2) over very dark gray (10YR3/1). The Land cover is cultivated land with sparsely scattered bushes. The soils have moderately fine and medium granular over strongly develop sub-angular blocky- structure. The consistence is hard when dry, friable when most and sticky and plastic when wet. The soils of this unit have broken distinct slickenside in subsurface soil. The infiltration rate is 0.9 cm/hr and it is an optimum level. The hydraulic conductivity is very slow (0.12 m/day). The bulk density is 1.56 g/cm3 on surface soil and increased to C horizon. These soils have high available moisture with value of 200 mm/m. The pH value on surface soils 7.53 on surface soil, which indicates that the soils are slightly alkaline. Beneath surface soil the soil reaction is moderately alkaline (pH=8.24).The soils are non-saline with an average value of EC 0.52 mS/cm. The soil is moderately sodic with an average value of on top soil up to the depth of 100cm 11.85%. The soil is calcareous with value of 12.12%. The soils have high CEC with value of 75.53 meq/100g and decreased with depth. The percentage base saturation is greater than 100%soil through out the profile because of the presence of CaCO3. The value of organic carbon is very high with value of 3.33% and it reduces down ward the profile up to 1.04%. The value of total nitrogen on top soil is very high 0.47% and reduced with depth. The ratio of organic carbon to nitrogen is 7. The available phosphorus on surface soil is 5.31 ppm. Below surface soil it reduces with depth. These soils have medium level exchangeable sodium on top and increased with depth. Thus, it might affect the fertility status. The exchangeable potassium is very high with value of 2.47 meq/100g soil on top WWDSE In Association with ICT Final Feasibility Study Roport 77Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Balo Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study soil. Under surface soil it decreased up to 0.45 meq/100g soil. These soils have very high calcium content on top soil 63.62 meq/100 g soils, and under surface soil it is also at very high level But it decreased with depth. The magnesium level is vey high with value of 10.3 meq/100g soils on top soil and in sub-soil it increased down ward the profile. The ratio of Ca: Mg is 6 and it may prohibit the availability of magnesium and phosphorus. The proportion of potassium to magnesium is 0.24 and it is favorable for vegetables crops. Model Soil Profile Description Profile code: BGP-28 Mapping unit: VB1 moVRca-wnA Status: Sampled profile Date: 01/07/08 Soil classification, fao (2006): Mollie Vertisols (Calric, Hyposodic) Coordinates, Long (N): 0790036 Lat (E): 0663401 Elevation: 1799 Author: Atelbachew, Eyouale Land form: Valley floor Relief intensity: <100 - Map sheet No. 0740 C4 _ Regional slope: Flat to gently undulating Depth to bedrock: >200 cm Slope class: Very gently slope Rock out crops: None Slope form: Convex stones Position: Medium Micro topography: Level Parent material: Alluvial deposits cultivated land Effective soil depth: Very deep cultivation Surface coarse fragments: Few coarse gravel & Surface cracks: Wide Surface sealing: weak Land cover: Settlement & Intensively Land use: Residential use & rain fed arable Drainage class: Drainage external: Water table: Well drained Well None Fertilizers: None Erosion status: Slight sheet & splash erosion Flooding: None 0-25 cm: Dark grayish brown (10 YR 3/2 ) when moist; clay texture; weak fine granular structure; friable when moist, very sticky & very plastic when wet; few white both hard and soft carbonate nodules ; many coarse roots; many coarse pores; strongly calcareous ;clear and smooth boundary 25-95 cm: Very dark gray (10 YR 3/1) when moist; clay texture; very few medium gravel rock fragment; moderate coarse sub angular blocky structure; very firm when moist; very sticky & very plastic when wet; continuous prominent slickensides cutans. cemented nodular clay & carbonate cem/comp; common white both hard and soft carbonate nodules & segregation; common medium roots; common fine and medium pores; extremely calcareous; clear and smooth boundary. 95-140 cm: Dark gray (10 YR 4/1) when moist; clay texture; moderate medium angular blocky structure; very firm when moist; very sticky & very plastic when wet; broken distinct slickenside & clay cutans; many white both hard and soft carbonate nodules & segregation ; few fine roots; few fine pores; extremely calcareous ; diffuse boundary. 140-200 cm: Dark grayish brown (10 YR 4/2)when moist; day texture; moderate medium angular blocky structure; very firm when moist, very sticky & very plastic when wet; broken distinct slickenside cutans; dominant white both hard and soft carbonate nodules & segregation ; few fine pores; extremely calcareous . WWDSE In Association with ICT Final Feasibility Study Ro port 78Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility jtudy and Detail Design of Bale Gadula irrigation Project VOL 5- ANNEX 4 Soil Survey Study 10.2.13 Soil Mapping Unit VB2haLVhe-clB This unit refers to the soils developed on very gently undulating colluvial/alluvial plain land (1-2% slopes). These soils were formed on basalt parent material. It is classified as Haplic Luvisols (Hypereutric, clayic) Stony phase and its total extent is 200 ha (2.6%). The soils are deep (140 cm) with well drainage, very dark grayish brown (10YR4/2) over dark brown (7.5 YR 3/2) and clay through out profile. The Land cover is sparsely cultivated land with open woodland. On surface these soils have many stones and boulders. The soils of this unit have distinct clay cutans pedface in subsurface soil. The clay content on surface soil is 53.36%. Under surface soil the clay content increased up to 67.87%.The consistence is very hard when dry, friable when moist and very sticky and very plastic when wet .The soils have strong fine angular blocky over moderate medium sub angular blocky structure. This mapping unit is affected by rill and gully erosion. The infiltration rate is 3.4 cm/hr and it is at required level. The hydraulic conductivity measurement is very slow (0.12 m/day). The bulk density is 1.71 g/cm3 on upper horizon and increased to B horizons. The available water holding capacity is 246 mm/m. The pH value on surface soils is 6.37, which indicate that the soils are slightly acidic. Beneath surface soil also it is slightly acidic (pH=6.72).The soils are non saline with an average value of EC 0.06 mS/cm. The soil is non sodic with an average value of on top soil up to the depth of 100cm 0.48%. The CEC is very high, with value of 50.56 meq/100g soil soil on surface soil. Under surface soils it mildly decreased up to 43.23 meq/100g soil. The soils have high BS% with 61%. The value of organic carbon is 2.5% on upper horizon and decreased with depth. The value of total nitrogen on top soil is 0.32%, depicting that it is at very high class. Beneath surface soil it decreases up to 0.11%. The ratio of organic carbon to nitrogen is 7. The available phosphorus on surface and sub soil is very low. These soils have low exchangeable sodium (0.16 meq/100g soil) on surface soil. Beneath surface soil it is low with slight change 0.2 meq/100 g soils. Thus, as far as it is less than 1 meq/100g soil, it might not have any negative effect on soil property. The exchangeable potassium is 0.68 meq/100 g soil on top soil, which shows that it is at high level Under surface soil it is also at medium level (0.48 WWDSE In Association with ICT Final Feasibility Study Report 79Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale GadulaJrngat|on Project^^ VOL 5- ANNEX 4 Soil Survey Study meq/100g soil). These soils have very high calcium content on top soil (24.17meq/100 g soils) and under surface soil it increased slightly to Ck horizon (37.06 meq/100 g soils). The soils have high magnesium 5.93 meq/100g soils on top soil and in sub-soil it increased to B horizon (6.33 meq/100 g soils). The ratio of Ca: Mg is 4 and it is at required level. The proportion of potassium to magnesium is 0.1 and it is favorable for vegetables crops. Model Soil Profile Description Profile code: BGP-35 Mapping unit: VB2haLVhe-clB Date: . Status: Sampled profile 16A)7A)9 Soil classification, FAO (2006): Haplic Luvisols (Hypereutric, clayic) stony phase Coordinates, Long Author: (N): 0782041 Lat (E): 0665415 Elevation: 1788 Atelbachew & Eyouale Land form: Valley floor Relief intensity: <100 Map sheet No. 0740 C4 Regional slope: Flat to gently undulating Depth to bedrock: >200 cm Slope class: Slope form: Position: Very gently slope Convex Rock out crops: None Surface coarse Frag.: Few stones & coarse gravel High Surface cracks: Fine Surface sealing: None Micro topography: Level Parent material: Alluvial deposits Land cover: Intensively cultivated land & open shrub land Effective soil depth: Very deep Drainage class: Well drained Drainage external: Well Land use: Rain fed arable cultivation & Extensive grazing Fertilizers: None Water table: None Erosion status: Slight sheet & splash erosion Flooding: None 0-26 cm: Very dark brown (10 YR 2/2 )when moist; clay texture; moderate medium granular structure; friable to firm when moist, very sticky & very plastic when wet; patchy faint slickenside cutans; common fine and medium roots; common coarse pores; moderately calcareous ; diffuse boundary. 26-80 cm: Black (10 YR 2/1)when moist; clay texture; moderate coarse sub angular blocky & angular blocky structure; firm when moist, very sticky & very plastic when wet; continuous distinct slickenside cutans; few white soft carbonate segregation ; common fine roots; common fine and medium pores; strongly calcareous .clear and smooth boundary 80-137 cm: Very dark gray (10YR 3/1) when moist; clay texture; moderate medium sub angular blocky structure; firm when moist, very sticky & very plastic when wet; continuous distinct slickenside cutans; common white soft carbonate segregation ; very few fine roots; common fine pores; strongly calcareous ;clear and smooth boundary 137-200 cm: Dark gray (10 YR 4/1) when moist, clay texture; moderate medium sub angular blocky structure; firm when moist, very sticky & very plastic when wet; continuous distinct slickenside cutans; common white soft carbonate segregation; common fine pores; strongly calcareous. 200-240 cm; Very dark grayish brown (10 YR 3/2) when moist; clay texture; very sticky & very plastic when wet; many white both hard and soft carbonate segregation & nodules; extremely calcareous. 240-370 cm: Dark gray (10YR 4/1) when moist; clay texture; very sticky & very plastic when wet; many white both hard and soft carbonate segregation & nodules; extremely calcareous. WWDSE In Association with ICT Final Feasibility Study Report 80Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5- ANNEX 4 Soil Survey Study 370-450 cm' Dark grayish brown (10 YR4/2) when moist; clay texture; very sticky &very plastic when wet; many white both hard and soft carbonate segregation & nodules; extremely calcareous. 10.2.14 Soil Mapping Unit VB1haLVhe-crB This unit refers to the soils developed under intensively cultivated land on very gently undulating colluvial/alluvial plain land (1-2% slopes). These soils were formed on alkaline olivine basalt parent material and according to WRB, 2006 classified as Haplic Luvisols (Hypereutric, Chromic).The mapping unit covers an area of 532 ha or about 6.9% of the project area. The textural class of the whole profile is clay with clay content 48.75% on surface soil. Under surface soil Clay increases with depth in all the soil profiles and highest at the Ck horizons (61.45%).The color of the soil is dark brown (7.5YR 3/3) over very dark brown (7.5YR2.5/2). The soil structure is moderate medium granular structure over strong medium to coarse sub-angular blocky. Consistence is hard when dry, friable when moist and very sticky and very plastic when wet. The drainage class is well drained and few surface coarse fragment. The depth of the pedon is very deep (185 cm). The land cover is open shrubby land with sparsely moderately cultivated land. The infiltration rate measurement is 1 cm/hr and it is with in optimum range The hydraulic conductivity is 0.11 m/day and categorized in to very slow The bulk density is 1.45 g/cm3. The soil moisture of the soils is medium level (165 mm/m). The pH value of the topsoil is 6.92, showing that the soil reaction is slightly acidic. In sub surface the soil reaction is slightly alkaline (pH=7.84). The soils have moderately high organic carbon and its value is 1.75% and decreases downward the profile (1.40-0.1%). The content of total nitrogen of the area is at medium level 0.22% on surface soil. Under surface soil it reduces to 0.01%. The proportion of organic carbon and total nitrogen is 8 showing it is favorable. The available phosphorus is low ppm with value of 4.41 ppm on top soils and decreased with depth. The cation exchange capacity of topsoil is very high and it is 52.59 meq/100gm of soil. The value slightly decreased downward the profile up to 27.76 meq/100g soil. The average base saturation percentages of all soils are 78% at surface soil and increased with depth up to 141% at Ck horizon. WWDSE In Association with ICT Final Feasibility Study Roport 81Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soli Survey Study The soil is non saline with an average value of EC 0.12 mS/cm and in addition to that the soil is non sodic with an average value of 0.51%. This mapping unit is slightly calcareous with value of 2.47%. The exchangeable sodium (Na) is low through out the profile (0.13meq/100g soil) and thus, it might not induced any adverse effect on soil property. The exchangeable of potassium is high with value of 1.53 meq/100 g soils on top soil and in sub soil it reduced and reached up to 0.67 meq/100g soil. The value of calcium of this unit is very high on surface soil and its content is 31 81 meq/100 g soils and increased to Bk horizons (47.94 meq/100g soil). The Mg is at high level (7.62 meq/100g soil) on surface soil and decreased with depth. The ratio of Ca: Mg is 4 it is optimum for many crops. The proportion of potassium to magnesium is 0.2 and it is favorable for vegetables crops. Model Soil Profile Description Profile code: BGP-39 Mapping unit: VB1haLVhe-huB Status: Sampled profile Date: 09/07/09 Soil classification, FAO (2006): Luvisols (Eutric) Coordinates, Long (N): 0783007 Author: Kinfe & Eliays Lat (E): 0668385 Land form: Valley floor Elevation: 1736 Relief intensity: <100 Map sheet No. 0740 D3 Regional slope: Flat Depth to bedrock: >185 cm Slope class: Neatly level Rock out crops: None Slope form: Uniform Surface coarse fragments: Very few stones Position: Low Surface cracks: Fine to medium Micro topography: Animal tracks Surface sealing: None Parent material: Alluvial deposits Land cover: Intensively cultivated land, open shrub & bush land Effective soil depth: Very deep Land use: Rain fed arable cultivation & Extensive grazing Drainage class: Moderate well drained Fertilizers: None Drainage external: Well Water table: None Erosion status: Slight sheet 5 splash erosion Flooding: None 0-30 cm: Dark brown (7.5 YR 3/3) when moist: silty clay texture; strong medium to coarse granular structure; firm when moist, sticky & plastic when wet; many medium and coarse roots; abundant medium and coarse pores; non calcareous; dear and smooth boundary. 30-130 cm: Very dark brown (7.5 YR 2.5/2) when moist; day texture; strong medium and coarse angular blocky structure; very firm when moist, very sticky & very plastic when wet; continuous prominent slickenside cutans; few white both hard and soft carbonates nodules & concretion ; common fine and medium roots; many fine and medium pores; extremely calcareous ; dear and smooth boundary. 130-185 cm: Dark red (2.5 YR 4/6) when moist; day texture; many medium and coarse gravel rock fragment; strong medium and coarse angular blocky structure; firm when moist, sticky & plastic when wet; continuous prominent slickenside cutans; abundant white both hard and soft carbonates nodules & concretion; many medium and coarse pores; extremely calcareous. WWDSE In Association with ICT Final Feasibility Study Report 82Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study 3 10.2.15 Soil Mapping Unit PiccLVhe-crC This mapping unit is situated in gently piedmont plain with slope gradient of 2-4% and according to WRB, 2006 classified as Calcic Luvisols (Hypereutric, Chromic). It covers some 67 ha of land, which account 0 9 % out of the total surveyed area. The color of these soils are dark brown (7.5YR 3/2) over very dark brown (7.5YR3/1). The textural class of the top soil is clay loam with clay content 38.11% on top soil and increased considerably up to 78.70% at 110 cm depth. Moderate, fine granular structure on surface soil and strong over angular blocky structure in sub soil has been noted. Consistence is very hard when dry, friable when moist and very sticky and very plastic when wet. The drainage class is well drained. On surface soil is presented very few coarse fragments. The Land cover is open shrub land and used for extensive grazing The depth of the pedon is very deep (200 cm). The infiltration rate and hydraulic conductivity measurement is 1 cm/hr and 0.11 m/day respectively. The rate of infiltration is suitable for surface irrigation. The test of hydraulic conductivity is very slow. The bulk density is 1.46 g/cm . The water holding capacity is 139 mm/m and it is medium level. The soil reaction of the top soil is moderately alkaline with pH value of 8.02 on surface soil. Beneath surface soils at he soil reaction is strongly alkaline (pH=8.71). On top soil the organic carbon is very high (3.80%) and decreased downward the profile (1.5-1.14%). The content of total nitrogen on surface soil of the area is 0.51% at very high level. Under surface soil it decreases (0.17-0.09%). The proportion of organic carbon and total nitrogen is 8. The status of the available phosphorus on top soil is very low (3.5 ppm). In sub soils its content is decreased Hence, application phosphorus fertilizer is a must. The average cation exchange capacity of topsoil is high to very high and it 59.9 meq/100g soil. It decreased with but showing no significant variation from upper horizon, indicating that the soil mapping unit, is fertile. The base saturation percentages of all soils are very high and it exceeds 100% due to presence of high Calcium. The soil is non saline with an average value of EC less than 0.4 mS/cm the soils are sodic with value of 15.47%. This mapping unit is calcareous with value of 15.03%. The exchangeable sodium (Na) of the surface soil is 0.43 meq/100g soils. Beneath surface soil content of sodium is very high at Bt horizon (7 99 WWDSE In Association with ICT Final Feasibility Study Report 83Federal Democratic Republic of Ethiopia- Ministry of Wator Resources Feasibility Study and Detail Design of Balo Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study meq/100g soil), showing that in the value is greater than 2 meq/100g soil and will induced any negative effect on soil property. Therefore, it requires mitigation measure, such as gypsum. The exchangeable of potassium is very high (1.32 meq/100g soil) on surface soil. In sub soil potassium decreased with depth. The value of calcium of this unit is at very high level with value of 56.45 meq/100g soil. In sub soil it decreased up to 46.59 meq/100g soil at Bt horizon. The Mg is at high level with value of 4.03 meq/100g soil on top soil. In sub surface it increased with up to 22.40 meq/100g soil to depth Bt horizons. In general the exchangeable magnesium is at high level. The proportion of magnesium to calcium is 14, indicating that magnesium and potassium will not be available due to over dose of calcium and alkaline soil reaction. The ratio of potassium to magnesium is 0.33 and it is good for most of vegetable crops. Model Soil Profile Description Profile code: BGP-43 Mapping unit: PiccLVhe-crC Status: Sampled profile Date: 23/07/09 Soil classification, fao (2006): Calcic Luvisols (Hypereutric, Chromic) Coordinates, Long (N): 0781000 Lat (E): 0670400 Elevation: 1979 Author: Land form: Relief intensity: Regional slope: Slope class: Slope form: Position: Micro topography: Fekadu & Taddese Valley floor <100 Gently undulated Gently slope Uniform Low None Map sheet No. Depth to bedrock: Rock out crops: 0740 D3 >200 cm None Surface coarse fragments: Very few stones Surface cracks: Surface sealing: Parent material: Alluvial deposits over colluvial Land cover: Effective soil depth: Very deep Drainage class: Well drained Drainage external: Well Medium None Open shrub land Nomadism None None Water table: None Land use: Fertilizers: Erosion status: Flooding: None 0-35 cm: Dark brown (7.5 YR 3/2 )when dry, very dark brown (7.5YR 2.5/3)when moist; clay loam texture; strong fine and medium granular structure; hard when dry, very friable when moist, sticky & plastic when wet; many fine to coarse roots; common earth worm channels ; many fine to coarse pores; strongly calcareous 35-110 cm: Very dark gray(7.5 YR 3/1)when dry, dark brown (7.5YR 3/2 )when moist; clay loam texture; strong medium and coarse angular blocky structure; hard when dry, very friable when moist, sticky & plastic when wet; broken faint clay cutans; common fine roots; few earth worm channels ; many fine and medium pores' strongly calcareous. 110-180 cm: Very dark brown (7.5 YR 2.5/3) when moist; clay texture; few fine gravel rock fragment, medium and coarse angular blocky structure; firm when moist, sticky & plastic when wet; broken distinct clay cutans; compacted platy clay; very few very WWDSE In Association with ICT Final Feasibility Study Report 84Fodcral Democratic Republic of Ethiopia- Ministry of Wator Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5- ANNEX 4 Soil Survey Study fine roots; many fine and medium pores; strongly calcareous. 180-200 cm: Dark brown (7.5 YR 3/3)when moist; clay texture; few fine gravel rock fragment; medium and coarse angular blocky structure; firm when moist, sticky & plastic when wet; broken distinct clay cutans; compacted platy clay; common red soft iron segregation ; very few very fine roots; few fine pores; strongly calcareous. 10.2.16 Soil Mapping Unit VBIvrLPcaA This unit refers to the soils developed under intensively cultivated land on nearly level colluvial/alluvial plain land (0-1% slopes). These soils were formed on alkaline olivine basalt parent material and according to WRB, 2006 classified as Vertic Leptosols (Caicaric, Humic). The mapping unit covers an area of 610 ha or 7.9% of the project area. The land cover is mainly dense shrub wood land with scattered cultivated land. The effective soil depth is shallow (40 cm). The textural class of the whole profile is silty clay loam. The clay content of top soil is 29.4%. In sub surface the clay is varying from 57.39 to 82.26%. The colour of top soil is very dark gray (10YR3/1) and in sub soil very dark grayish brown (10 YR3/2). The soil structure is weak fine granular structure on surface soil. Consistence is hard to very hard when dry, firm when moist and very sticky and very plastic when wet. The drainage class is somewhat excessive and many surface coarse fragment. In sub-surface soils common too many calcium mineral nodules are present. The bulk density is 1 30 g/cm The available moisture content is at medium level with value of 135 mm/m. The pH value of the topsoil is 7.71, showing that the soil reaction is slightly alkaline. The organic carbon on top soil is 2.68%, showing that the organic carbon is very high. The content of total nitrogen on surface soil is very high with value of 0.38. The proportion of organic carbon and total nitrogen 7 and it is at optimum level. The available phosphorus is at medium level with value of 5.38 ppm. The cation exchange capacity is very high and it is 66.71 meq/100gm of soil The base saturation percentages of all soils is very high (105%) because of the presence of high calcium carbonate. The soil is non saline with an average value of EC 0.2 mS/cm. The soil is non sodic with value of ESP 0.32%. This mapping unit is calcareous with value of 6.17%. The exchangeable sodium (Na) of the top profiles is 0.21 meq/100g soil. The exchangeable of potassium is medium with value of 1.08 meq/100g soil on surface soil. The value of calcium of this unit is at very high 3 WWDSE In Association with ICT Final Feasibility Study Report 85Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Dosign of Bale Gadula irrigation Project VOL 5-ANNEX 4 Soil Survey Study level and its content is 61 82 meq/100 g soils. The Mg is high (7.17 meq/100g soil). The ratio of Ca: Mg is 8. The availability of magnesium and phosphorus will be limited because of high concentration of calcium and soil alkalinity. The proportion of potassium to magnesium is 0.03 and it is favorable for vegetables crops. Model Soil Profile Description Profile code: BGP-45 Mapping unit: VB1 vrLPcaA Status: Sampled profile Date: 24/07/09 Soil classification, FAO (2006): Vedic Leptosols (calcaric,Humic) ) Coordinates, Long (N): 0782072. Lat (E): 0671416, Elevation: 1688 Author: Addisu & Eyoulae Land form: Valley floor Relief intensity: <100 Map sheet No. 0740 D3 Regional slope: Flat to gently undulating Depth to bedrock: 40 cm Slope class: Nearly level Rock out crops: None Slope form: Convex to Concave Surface coarse fragments: common sfonw & many boulders Position: Lowest Surface cracks: None Micro topography: Level Surface sealing: weak Parent material: Basalt Land cover: Intensively cultivated land Effective soil depth: Shallow cultivation Land use: Drainage class: Moderate well drained Fertilizers: Rain fed arable None Drainage external: Slow Water table: None Flooding: None Erosion stati&: ’ ‘ None 0-32 cm: Very dark grayish brown (10 YR 3/2) when moist; clay texture; weak medium granular structure; very friable when moist, very sticky & very plastic when wet; common white both hard and soft carbonate segregation & nodules; common fine and medium roots; many fine and medium pores; extremely calcareous.; clear and smooth boundary 32-40 cm: Saprolite, dominant white hard carbonate nodules; extremely calcareous. WWDSE In Association with ICT Final Feasibility Study ReportFederal Democratic Republic of Ethiopia- Ministry of Water Rosources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5- ANNEX 4 Soil Survey Study 10.2.17 Soil Mapping Unit PiccVRhu-peA The mapping unit covers an area of 313 ha or about 4.1% of the project area. This mapping unit is situated undulating plain with slope gradient of 2-4% and according to WRB, 2006 classified as Calcic Vertisols (Humic, Pellic), Stony phase. The land cover is moderatly cultivated land The textural class of the soils is clay. The clay content of top soil is 62.07%. Clay increases with depth in all the soil profiles and highest at the Ck horizons up to 74.76%.The colour of top soil is very dark gray (10YR3/1) and in sub soil is black (10YR2/1). The soil structure is moderate fine and medium granular over strong coarse angular blocky structure. Consistence is hard to very hard when dry, firm when moist and very sticky and very plastic when wet. The drainage class is imperfect and many surface coarse fragments. In sub-surface soils common to many calcium and manganese mineral nodules are present. The depth of the pedon is very deep (>200 cm). The soils of this unit have common and many distinct slickensides in subsurface soil. The infiltration rate measurement is 3.1 cm/hr and thus, the test result is optimum for surface irrigation. The hydraulic conductivity test result is 0.06 m/day, which is very slow. The bulk density is 1.17 g/cm . The available water holding capacity is 200 mm/m. The pH value of the topsoil is slightly alkaline (pH=7.84). In Sub soil the soil reaction moderately alkaline (pH=8 13). The organic carbon on top soil is 2.4%, showing that the organic carbon is categorized in to high class. As usual its value decreases downward the profile up to 0.2%. The content of total nitrogen on surface soil is 0.25%, indicating that it is at high level. Like organic carbon the total nitrogen decreases in subsurface soil up to 0.02%. The proportion of organic carbon to total nitrogen is 10. Generally, the soil organic matter is at optimum level. The available phosphorus is very low, 4.61 ppm on top soil and decreased with depth. The cation exchange capacity of topsoil is 72.56 meq/100gm of soil and increased to Bw (82.30 meq/100 soil). The base saturation percentages of all soils are very high with value of 61% on upper horizon and increased with depth. The soil is non saline with an average value of EC 0.15 mS/cm. The soil is non sodic and the maximum Value of ESP of on top 100 cm depth is 0.83%. This mapping unit is calcareous with value of 23.00%. The exchangeable sodium (Na) 3 WWDSE In Association with ICT Final Feasibility Study Report 87Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study of the top soil is low (0.21 meq /100g soil). Whereas in subsurface Isightly increased with depth up to 0.77 meq/100g soil. As far as, the value is less than 1 meq/100g soil hence, sodium might not negatively affect the soil property. The exchangeable of potassium is high with value of 1.15 meq/100g soil on surface soil and decreased mildly with depth. The value of calcium of this unit on top soil is at very high level and its content is 36.29 meq/100 g soils. Beneath surface soil exchangeable calcium increased to Bk (58.24 meq/100g soil).The Mg is high with value of 6.27 meq/100 g soils on surface soil. In sub soil also it increased to very high level at Bk horizon up to 23.74 meq/100g soil. The ratio of Ca: Mg is 6. Thus, the value is not conducive for most crops and there might be limitation of availability of Phosphorus and magnesium. The proportion of potassium to magnesium is 0.2 and it is favorable for vegetables crops. Model Soil Profile Description Profile code: BGP-56 Mapping unit: PiccVRhuA Date: Soil classification, FAO (2006): Calcic Vertisols (Humic, Coordinates, Long (N): 0783150 Lat (E): 0665963 Elevation: 1777 Author: Addisu Land form: Valley floor Relief intensity: <100 Map sheet No. Regional slope: Gently undulated Depth to bedrock: Slope class: Gently slope Rock out crops: Status: Sampled profile 16/07/09 Pellic), Stony phase 0740 D3 >200 cm None Slope form: Convex Surface coarse fragments: Many medium gravel & stones Position: Medium Surface cracks: Surface sealing: weak Fine to medium Micro topography: Level Parent material: land Alluvial OVer Colluvial Land cover: Predominantly cultivated land, open wood 8 shrub Effective soil depth: Very deep grazing Drainage class: Moderate well drained Drainage external: Rapid Water table: None Land use: Rain fed arable cultivation & Extensive Fertilizers: None Erosion status: None Flooding: None 0-20 cm: Very dark gray (10 YR 3/1) when moist; day loam texture, few fine gravel rock fragment; weak medium sub angular blocky structure; friable when moist; sticky & plastic when wet; very fine white hard carbonate nodules ; abundant fine and medium roots; abundant fine pores, strongly calcareous; clear and smooth boundary. 20-110 cm: Black (10YR 2/1) when moist; clay texture; common fine and medium gravel rock fragment; moderate fine and medium angular blocky & sub angular blocky structure; firm when moist, very sticky & very plastic when wet; continuous prominent slickensides cutans; common white hard carbonate nodules; common fine roots; many fine pores; extremely calcareous; clear and smooth boundary. 110-160 cm: Dark red (2.5YR 3/6 )when moist; clay loam texture; many medium gravel rock fragment; moderate fine and medium angular blocky structure; firm when moist, WWDSE In Association with ICT Final Feasibility Study ReportFederal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Balo Gadula Irrigation Project VOL 5- ANNEX 4 Soil Survey Study sticky & plastic when wet; continuous prominent slickenside cutans; moderately cemented nodular silica; many white hard carbonate nodules; few fine roots; common fine and medium pores; extremely calcareous; diffuse boundary. 160-200 cm: Dark red (2.5YR 3/6) when moist; clay loam texture; common coarse gravel rock fragment; weak to moderate medium angular blocky structure; friable when moist, sticky & plastic when wet; broken distinct clay cutans; common white hard carbonate nodules; common fine pores; extremely calcareous. 10.2.18 Soil Mapping Units PimoVRca-huC The mapping unit covers an area of 225 ha or about 2.9%% of the project area. The soils of this unit are classified as Mollie Vertisols (Calcaric, Humic), according to WRB, 2006. This mapping unit is developed from in situ weathered basaltic parent material on piedmont plain (2-4%) landform. The soils in this unit are clay textured through out the profile. The clay content on surface soil is 61.11%. It increases with depth in all the soil profiles and highest at the Bt horizons up to 77.32%. It is very deep (200 cm) with imperfectly drained and few and no surface coarse fragment. The colour of the soils is very dark gray (10YR 3/1) over black (10YR2/1). The Land cover is open bushy woodland with sparsely cultivated land. The soils have moderately developed fine and medium granular structure on surface soil and moderately developed medium sub-angular blocky-structure. The soils of this unit have broken distinct slickenside in subsurface soil. The infiltration rate is 5.1 cm/hr and it is suitable for surface irrigation. The hydraulic conductivity is 0.07 m/day and it categorized in to very slow class. The bulk density is 1.81 g/cm3 at Bt horizons and hence soil compaction will be a major limitation. However, it decreased with depth up to 1.43 g/cm3 at Bk horizons. The available moisture content is 200 mm/m, indicting that it is at high level. The pH value on surface soils is 6.74, which indicates that the soils are slightly acidic. Beneath sub soil it is strongly alkaline (pH=8.92) to Bt horizons. The soils are non-saline (EC=0.37 mS/cm) and slightly sodic with value of EPS=13.42%. So these soils are required application o gypsum. The soils are calcareous with value of 9.2%. The soils have very high CEC (81.32 meq/100g soil) on top soil. While under sub soils it decreased with depth (73.85 to 54.52 meq/100g soil). The soils have high BS% (83%) on surface soil and increased considerably by exceeding WWDSE In Association with ICT Final Feasibility Study Report 89Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study 100%. The organic carbon is very high with value of 5.07% on surface soil. While under sub surface it decreases up to 1.64%. The value of total nitrogen on top soil is 0.48%. depicting that it is at very high level. Beneath surface soil it decreased. The ratio of organic carbon to nitrogen is 11. The available phosphorus on surface soil is 1.69 ppm, indicating that it is at very low level and decreased with depth. These soils have high exchangeable sodium, rating 2.08 meq/100 g soils on surface soil and increased paramount with depth and highest at the Bt horizon (9.91 meq/100g soil). Thus, it might have an adverse effect on fertility status. The exchangeable potassium is at medium level (0.48 meq/100g soil) on top soil and decreased with depth. These soils have very high calcium content with value of 62.72 meq/100 g soils on top soil and increased with depth with all profiles and highest at the Ck horizon. The magnesium level is medium (2.24 meq/100g soils) and in sub-soil it increased with depth and highest the Bk horizon up to 30.55 meq/100g soil. The ratio of Ca: Mg is 28 and it may prohibit the availability of phosphorus and phosphorus. The proportion of potassium to magnesium is 0.2 and it is favorable for vegetables crops. Mollie Vertisols (Calcaric, Humic), Model Soil Profile Description Profile Code: Bgp-64 Mapping Unit: Pimovrca-Huc Status: Sampled profile Date: 25/07/09 Soil classification, fao (2006): Mollie Vertisols (Calcaric, Humic), Coordinates, Long (N): 0784000 Lat (E): 0659400 Elevation: 7877 Author: Dawit & Tilahun Land form: Relief intensity: Regional slope: Slope class: Slope form: Position: Micro topography: Parent material: Valley floor <100 Flat to gently undulating Map sheet No. Depth to bedrock: Nearly level to very gently Rock out crops: 0740 C4 >200 cm None Uniform Low Gilgai Alluvial deposits Effective soil depth: Very deep Drainage class: We// drained Drainage external: Well Surface coarse fragments: Very few stones Surface cracks: Medium to wide Surface sealing: None Land cover: Intensively cultivated land & Open shrub & bush land Land use: Ram fed arable cultivation & Extensive grazing Fertilizers: None Water table: None Erosion status: Moderate rill & sheet erosion Flooding: None Very dark gray (10 YR3/1) when moist; clay texture; moderate coarse granular structure; firm when moist, very sticky & very plastic when wet; abundant medium and coarse roots; abundant medium and coarse pores; non calcareous; clear and smooth boundary. Black (10YR 2/1)when moist; clay texture; moderate medium and coarse sub WWDSE In Association with ICT Final Feasibility Study ReportFederal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5- ANNEX 4 Soil Survey Study angular blocky structure; firm when moist, very sticky & very plastic when wet; continuous prominent clay cutans; few white both hard and soft carbonate nodules & concretion ; many fine and medium roots; many fine and medium pores; moderately calcareous ; gradual and smooth boundary. 80-145 cm: Very dark gray (10YR 3/1 )when moist; clay texture; moderate coarse sub angular blocky structure; firm to very firm when moist, very sticky & very plastic when wet; continuous prominent slickenside cutans; common white both hard and soft carbonate nodule & concretion ; few fine roots; few fine pores; strongly calcareous; clear and smooth boundary. 145-200 cm: Very dark brown (10YR 2/2 ) when moist; clay texture; moderate medium and coarse angular blocky structure; firm when moist, very sticky & very plastic when wet, continuous prominent slickenside cutans; many white both hard and soft carbonate nodule & concretion ; few fine roots; few fine pores; strongly calcareous. 10.2.19 Soil Mapping Unit VB1so-ccVRhu-peA The mapping unit covers an area of 53 ha or about 0.7% of the project area. The soils of this unit are classified as Sodi-Calci Vertisolsols (Humic, Pellic), according to WRB, 2006. The soils developed from basaltic parent material by colluvial over alluvial process on nearly level to level land (0-1%) landform. The soil texture of this unit is clay through out. The clay content on surface soil is 51.18%. Under surface soil the clay content is mildly increases and highest at the Bt horizon (65.76%). It is very deep (200 cm) with somewhat imperfectly drained and none or very few coarse fragments. The colour of the soils is black (10YR 2/1) over dark gray (10YR3/1). The Land cover is intensively cultivated land. The soils have strong fine and medium granular structure on top soil and moderately to strongly develop sub-angular blocky-structure in sub-surface soil. Consistence is hard when dry, friable when moist and sticky and plastic when wet. The soils of this unit have slickenside in subsurface soil. The infiltration rate is 5.1 cm/hr and it is suitable for surface irrigation. The hydraulic conductivity is 0.07 m/day and categorized in to very slow class. The bulk density is 1.47g/cm3 on surface soils and increased below surface soil and the highest value noted at depth of 65 cm. The soils have high level moisture holding capacity (222 mm/m). The pH value on surface soils is 8.98, which indicates that the soils are strongly alkaline and increased with depth up to extremely alkaline (pH=9.35). The soils are non-saline with EC value of 0.51 mS/cm. The soils are sodic with highest value of 18.69 % with in the depth of 0-100cm. Thus, it requires application of WWDSE In Association with ICT Final Feasibility Study Report 91Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study gypsum. The soils are calcareous with an average value of 16.27%. The soils have high CEC is on top soil (39.44 meq/100g soil. Under sub soils it is very high (49.18 meq/100g top soil. The BS% is very high and exceeding 100% through out the profile because of occurrence of free calcium carbonate. The organic carbon is very high with value of 2.82% on surface soil as usual it decreases. The value of total nitrogen on top soil is very high with value of 0.31% and decreased with depth. The ratio of organic carbon to nitrogen is 9. The available phosphorus on surface soil is very low with value of 2.66 ppm, and decreased with depth. These soils have high exchangeable sodium, rating 1.19 meq/100g soil on surface soil and increased with depth and the highest value is recorded at the C horizon (12.95 meq/100g soil). Thus, it might have an adverse effect on soils property. The exchangeable potassium is at very high level (1.39 meq/100g soil) on top soil Under surface soil it is low to medium status (0.78-1.04 meq/100g soil).’These soils have very high calcium content with value of 47.91 meq/100g soil on top soil and decreased with depth. The magnesium level is very high with value of 23.5 meq/100g soils on surface soil and in sub-soil it is increases up to 42.94 meq/100g soil. The ratio of Ca: Mg is 2.04 and it may inhibit the availability of phosphorus. The proportion of potassium to magnesium is 0.06 and it is favorable for vegetables crops Sodi-Calci Vertisolsols (Humic, Pellic), Model Soil Profile Description Profile code: BGP-68 Mapping unit: VB1so-ccVRhu-peA Status: Sampled profilo Date: 22/07/09 Soil classification, FAO (06): Sodi-Calci Vertisolsols (Humic, Pellic), Coordinates, Long (N): 0789742 Lat (E): 0650510 Elevation: 1955 Author: Alemu & Tilahun Land form: Valley floor Relief intensity: <100 Regional slope: Flat Slope class: Very gently slope Map sheet No. 0740 C4 Slope form: Position: Uniform Low Micro topography: Gilgai Parent material: Alluvial deposits Effective soil depth: Very deep Drainage class: Moderate well drained Drainage external: Slow Water table: None WWDSE In Association with ICT Depth to bedrock: >200 cm Rock out crops: None Surface coarse fragments: Very few stones Surface cracks: Medium Surface sealing: Moderate Land cover: Sparsely cultivated land Land use: Rain fed arable cultivation Fertilizers: None Erosion status: Slight sheet & splash erosion Flooding: None Final Feasibility Study ReportFederal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Doslgn of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study 0-30 cm: Black (10 YR 2/1) when moist; clay texture; moderate medium sub angular blocky structure; friable to firm when moist, very sticky & very plastic when wet; few white hard carbonate nodules; abundant fine and medium roots; abundant fine and medium pores; slightly calcareous; clear and smooth boundary 30-65 cm: Very dark gray (10 YR 3/1)when moist; clay texture; moderate medium and coarse sub angular blocky structure; firm when moist, very sticky & very plastic when wet; broken prominent slickenside cutans; many white both hard and soft carbonate segregation & nodules; many medium and coarse roots; many medium and coarse pores; strongly calcareous ; gradual and smooth boundary. 65-100 cm: Dark (10 YR 2/1) when moist; clay texture; weak fine sub angular blocky structure; firm when moist, very sticky & very plastic when wet; broken prominent slickenside cutans, abundant /few white /black both hard & soft /soft carbonate /manganese segregation & nodules; common fine and medium roots; common fine and medium pores; strongly calcareous; gradual and smooth boundary. 150-200 cm. Dark gray (10YR 4/1) when moist; clay texture; weak coarse sub angular blocky structure; firm when moist, very sticky & very plastic when wet; continuous prominent slickenside cutans; very few /many black /white soft / both hard and soft manganese /carbonate segregation & nodules; very few fine roots; very few fine pores; moderately calcareous. 200-245 cm: Very dark gray (10 YR 3/1) when moist; clay texture; firm when moist, very sticky & very plastic when wet; common white hard carbonate nodules & concretion; moderately calcareous. 10.2.20 Soil Mapping Unit -R: Steppe Side slopes, Stony and Eroded area is mainly occur in particular on hilly area and cover 699 ha and constitute 9% out of the total area. WWDSE In Association with ICT Final Feasibility Study Report 93646000 652000 658000 664000 670000 676000 ----------------------- ------------------------ 1______________________________ FEDERAL DEMOCRATIC REPUBLIC OF ETHIOPIA MINISTRY OF WATER RESOURCES WELMEL, YADOT AND BALE GADULA IRRIGATION PROJECTS PROJECT BALE GADULA IRRIGATION PROJECT SOIL MAPPING UNIT MAP SCALE 1:90,000 Figure 21602080 Legend >— Diversion weir River Contour 20m Command boundary Very deep, day loam over day. dark brown (7.5YR 3/2) over very dark brown PiLVhyC (7.5YR3/1). well drained, sub angular blocky structure, moderately sodic, -------- - developed on undulating land(2-4%), (Hyposodic Luvisols). Very deep, day, very dark gray (10YR 3/1) over black (10YR2/1), imperfect PiVRhv-oeC drain®d • moderate fine granular over sub angular blocky structure extremely i---------- ajlT— calcareous, very few on non stones, developed on undulating sloppy land (2-4%), (Pelk-Hyposodic Vertisols). Very deep, day, very dark gray (10YR 3/1) over black (10YR2/1). somewhat f ------------------------- imperfecty drained, granular structure over sub-angular blocky structure. I PjVRp®_4lCj Consistence is hard when dry. friable when moist and slightly sticky and slightly, slightly eroded and Common stones and boulders, strongly calcareous, developed on gently undulating plain (2-4%). (Pelll-Caldcc Vertisols), Very deep. day. very dark gray ish (10 YR3/2) to very dark brown (10YR2/2). imperfectly drained, fine granular over angular to sub angular blocky structure. PiVRSO-KC , Consistence ts hard when dry. friable when moist and slightly sticky and slightly few and Common stones and boulders, slightly eroded, developed on gently undulating plain (2-4%). (Sodi-Caldc Vertisols. (Chromic). Very deep. day. very dark gray (10YR3/1). imperfect drained , moderate fine PiWRca-rA granular over sub angular blocky structure, extremely calcareous, common to --------- many surface 6tones. developed on nearly level to level (0-1%). (Calcic Vertisols. Stony phase) Very deep. clay, very dark grayish brown (10YR 3/2) over very dark gray iVRSVDh a! 00YR3/1). imperfectly drained . weak fine granular over moderate medium _vpTVKnyso-crA | mjb anflU|ar blocky structure, few surface stones , developed on nearly level land (0-1%). (Chrom-Hyposodic Vertisols) Very deep, clay, dark gray (10YR 4/1) over dark brown (10YR3/3). somewhat [ I—yo'VHfy-jkA— common stones and boulders, developed under dense shrubby wood land VB1VRpe-kA ! Imperfectly drained, sub-angular blocky structure, moderately eroded and on nearly level (0-1%), (Pelli-Calcareous Vertisols) Very deep, sandy day loam over bay, , black (10YR 2/1) over very dark brown _____________ _. _ (10YR 2/2). imperfectly drained, sub angular blocky structure. Consistence is VB1VRso-crA 1 hard when dry, friable when moietand slightly sticky and slightly plastic. Common ’ stones and boulders, developed vsry gently undulating plsin (1-2%). (Chromi-Hypoaodic Vertisols. stony phase) __________(1?YR VB2VRhyso-p«B 51°!* i------------------- E—i moderately eroded . developed under on verv n.ntiu • <d -,-n d-l-8Ub-a—— n ular —wiwvfXJ OVUVlUt^, * over very brown •------------- =----- ------ i moderately eroded . developed under on very gently undulating (1-2%) ? * 9 blocky structure, (Hypo-sodic Vertisols. (Pellic). h I--------------------------- -(10 YR3/1). imperfectly drained, common stones and boulders t 1 ' TJ’? ’ray <,0YR 3Z2> ° vw ww dark » Very deep. clay, black (10YR 2/1) over dark gray (10YR3/1), Imperfect drained . moderate fine granular over sub angular blocky structure, extremely calcareous, very few on non stones, developed on nearly level land (0-1%), (Cald-Sodic Vertisolsols). Very deep day, very dark grey (1° R3/3) over black (10YR2/1), fine moderately | VB2VRp»-kB sub-angular blocky structure, Cons4stence is hard when dry friable when moist and slightly sticky and slightly . gently undulating plain (1-2%), ( Sodi-Caldc Vertisols, Pellic) VB1VR»o-kA | VB2VRpe-kC Y r~~~---------------- T“i developed s.ub-a. ngular. blocky over medium----m---ode -----r--a-t-e--ly...deu v. ej l»ope ub-dangular ! VB1VRso-p«A I blocky structure, common surfacestones and boulders, devedelopveeldoped on nearly level I VB2VRner.kB I 0YRR 2/2). some what Imperfectly drained, v Very deep, day loam over sandy clay loam, dark gray (10YR 4/1) over very dark gray (10YR 3/1), Imperfectly drained, fine granular over sub-angular blocky-structure, common surface stones, developed on gently undulating plain (2-4%). (Pelll- Calcic Vertisols). Very deep, day, very dark gray (10YR 3/1) over very dark brown (10YRR 2/2). some what Imperfectly drained, weak fine granular over I--------- — ■ ------- 1 moderate ficne and Jmediium sub-I angular blVocI_ ky 6tnjcture common to Shallow, silty day loam, is very dark grayish brown (10 YR3/2), excessively drained . moderate fine granular and/or wedge shape over sub angular blocky structure, extremely calcareous, very few on non stones, developed on nearly level to level (0-1%). (Eutric Leptosols) (0-1%). (Sodl-Calcic Vertisols) Very deep. clay, very dark gray* bro*n (10YR4/2) over dark brown (7.5 YR 3/2) ./.---------------~—I well drained . moderate medium 7 uiar over sub angular blocky structure, many VB2LVeu-<B J stones and boutderB. developed of very gentle undulating (1-2%), (Dystric Luvisols. Rudic). very deep, sandy day over day. clay over day), well rained, fine weakly f----------------------------i developed sub-angular blocky strongly calcareous, common surface _ VB2NTeu-rB 1 .tonesend boulders, developed unaer on very gently undulating (1-2%). (Eutric NitisolsolB). many surface stones, extremely calcareous, developed on gently undulating plain (1-2%), (Pelli-Calcic Vertisols). VB1 LPeuA Very deep, day, very dark gray (10 YR3/1) over black (10YR 2/1). — — —-------1 Imperfectly drained strongly develop sub-angular blocky-structure. VB2VRso-kB I Consistence Is hard when dry. friable when moist and slightly sticky VBILVeuB Very deep. day. 7.5YR 3/3) over very dark brown (7.5YR2.5/2). well drained, moderate medium granular structure over strong medium to coarse sub-angular blocky, extremely calcareous, developed on very gentle undulating land (1-2%), (Eutric Luvisols) end slightly few or no stones, developed on gently undulating plain 2% * ). (Pelli-Calcic Vertisols) ______ B I Steeply ia side slopes. Stony, and Bad Land nd 646000 652000 658000 664000 T 670000 676000 776000 780000 784000 788000 7920001Fcdoral Democratic Republic of Ethiopia- Ministry of Wator Rosourcos Feasibility Study and Dotail Design of Balo Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survoy Study Table 10.2: The Physical and Chemical Characteristics of Soil mapping Units of Balc-Gadula of Command Area Soil Mapping VB2CCVRhU-*lB VB2*O-CCVRhU- Poo-ccVRctt-siC PcCVHPlC VB1CCVR<V<<-CRA VB2maVRCA-HUC \ B2MOVKCA-HE VBICCVRplA VBioo-ccVRxu ►t -OTA________ VB2aaNThu-st1J VB2CCVR^.-P(B VB1MOVRCA v«.A VU2maLVhL<lB VBlMALVrtf <x8 P<CLVml<rC VB17WLPca-*iuA PccVRhu-piA PimoVRta-muC V81JO<CVKhu- R»K» Coidc Vortiiois (Hufntc.Poihc) Sodi-Caldc Vortlsols. (Hume. Pol Ic)_____________ Sod -Calcic Vortjsois. (Chromic), itony phaie Coidc Vortisoio (Pobc), prodod phaio_____________ Calcic Vontoois (Hypoaode, CrvomiCi_____________ Cu de Vortnoia (Humic, Polite) stony phoao Mollie Vortisolt (Coicartc. Polite). Coidc Vodnola [Poiticj Sod- Guice Vo<l »oi». (Hurmc PoWic)_______ Hopuc Nitnoijoli (Hume) atony phuio______________ Coidc Vortiac a. ;» 'posodc PoJc)____________________ Mollie Voiuao a (Colne. Mypooooc) _______________ i tuple LtMaoia (Hyporuutne. C‘Oy>c) Stony phuao I topic Lu>tiOu (I lypoioutne. Chrome___________________ Culcc Luvisoli (Myporoutre. Chrome Vofltc loptosols (Cueunc. Atomic)_________________ Calcic Vortisoli (Humic. Pel be), Stony phnoo Mouic Vonnou (Ca'conc I lumtc) Soot Coidc Von aoiioit (Humic Pugc; WWDSE In Association with ICT Final feasibility Study Roport 95L I L, l IL L IL L L r r r r r r r r r rFederal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula irrigation Project VOL 5-ANNEX 4 Soil Survey Study 11. CONCLUSIONS AND RECOMMENDATION 11.1 CONCLUSION Feasibility level soil study had been carried out in Bale-Gadula Irrigation Project covering 7739 ha of land. The main objective of the investigation was to provide detail information on the land and/or soils of the study area, which may form a basis for confirming/rejecting the irrigation potential, crop selection, irrigation design and agricultural input requirements such as fertilizer application. The' Bale-Gadula irrigation project area is found in the south-eastern part of the country and it stretches over some part of Goro, Sinana and Ginir wereds in Bale administrative zone of Oromiya Regional State. The project area is categorized in to traditional kola agro climatic zone with bio- modal rainfall system. The mean rainfall is estimated to be 998.7 mm/year .The average minimum temperature is 15.60C and the maximum temperature is 29.1 OC. The average monthly relative humidity is 69.42 %, the maximum is in November month 74.11%. The minimum value of RH is 57.64% in March. According to the 1973 edition of the Geological map of Ethiopia compiled by V.Kazmin, the project area is located on the boundary between the Basaltic flows and related spatter cones towards the north and west the lower complex towards the south the Dibigia and Genale Doria formation towards-east. The land form of the study area is mostly flat to almost flat land with in the slope range of 0-2%. The land cover of the project area is mainly made of open bush and shrub land, dense shrub land and moderate cultivated land. The major land use is agro- pastoralism. The head of Bale-Gadula River originates from high volcanic mountain of Mount Batu and finally drains to Genale-dawa River Basin. The project area is reachable by an asphalt road and graveled after traveling some 600 km from Addis Ababa via Shashemene to Bale-Robe and Goro towns. WWDSE In Association with ICT Final Feasibility Study ReportFederal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5- ANNEX 4 Soil Survey Study The present investigation adopted rigid grid survey techniques. The auger soil description has been made every 250 x 400m along transect to a depth of 1.20m. One auger observation represents for 10 ha area and the achieved observations include a total number of 779 auger observations and 75 profile pits observations, and 182 soil samples were collected from 48 profile pits and analyzed in WWDSE soil laboratory for standard analysis. Infiltration rate and hydraulic conductivity were measured in situ at 8 representative sites each in triplicates. To check the depth of the impervious horizon and to monitor the fluctuation of the water table 8 deep borings were made by auger boring from the bottom of the profile pits below 2m depth down to a depth of 3-5m on model profile sites. Soils of the project area are developed on colluvail and alluvial process. The soil classification o.f the study area has been made based on the World Reference Base for Soil (FAO, 2006). As a result of the investigation four major soil units namely: Vertisols, Nitisols, Cambisols, Luvisols, and Leptosols. The most extensive soil unit is Vertisols. The soils of project area have been grouped into 18 soil mapping units based on land form, chemical characteristics ( sodicity and calcareousness), phases such as stoniness, erosion and soil depth and soil units and in addition to that there have been identified 1 miscellaneous land unit. Soil nutrient status of the project site is generally moderately to high. The content of organic carbon of the area is very high; the soils have very high CEC & BSP and their soil reaction slightly acidic to extreme alkaline. Generally, value of CEC is very high. The content of phosphorus is from very low (0.00 ppm) to Very high (58.51 ppm) and the average value 3.38 ppm, indicating that in the project area there is deficiency of phosphorus. Thus, supplementary phosphorus fertilizer is highly required. The total nitrogen content of the soil is medium to high. The over all nitrogen value is between 0.01 and 0.69%; with an average value of 0.19%, showing that the status of total nitrogen is medium to high. Hence, application of supplementary nitrogen fertilizer is good. The presence of free carbonate indicates that exchangeable Ca, which usually implies favorable soil physical conditions, dominates the clay complex. Excess Ca, however can lead to deficiencies of some elements. In present work some WWDSE In Association with ICT Final Feasibility Study Report 97Federal Democratic Ropubllc of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Balo GaduU Irrigation Project VOL 5- ANNEX a Soil Survey Study results showed that the content of CaCOj is very high, ranging from trace to 32.31% with an average value of 17.09%. In general the over all content of exchangeable Ca is very high (18.53 meq/100g soil) to very high (75.94 meq/100g soil) with average of 47.10 meq/100 grams of soil. The over all exchangeable Mg is o high, varying from 0.90 to 70.78 with average value 15.49 meq/100 gram of soil. The reserve of K is medium to high (0.25 to 19.35 meq/100g soil with an average value of 1.11 meq/100g soil. Generally, the major constraints of the area are alkalinity/sodicity, erosion hazard, stoniness and dense vegetation cover. 11.2. RECOMMENDATION For existing constraints the following measures has been suggested: Gypsum application is necessary for amelioration of sodic soil. Sodidty problem has been noted on Soil Mapping Units of VB1so-ccVRhu-peB, VB1so-ccVRhu- peA, VB1ccVRwn-crA, Piso-ccVRcrstC and VB2so-ccVRhu-peB. The applicacation of gypsum has two basic elements: 11.2.1 Gypsum application Gypsum application is necessary for amelioration of sodic soil. Sodidty problem has been noted on Soil Mapping Units PL23 and PL22. It has two basic elements: i) Improvement of the porosity of subsurface soil and ii) Lowering of the ESP One of the methods is application of gypsum to lower the ESP by repladng sodium by divalent elements. This can be calculated on the equivalent basis of sodium to be replaced by calcium though adding gypsum in sodic soil. The step — by - step procedure for determining the amount of gypsum required to reclaim a sodic soil is given below. 1) The basic principle governing the use of gypsum, as an amendment is that 1 meq of Ca++ will replace 1meq of NaX (adsorbed Na+ ion) and it is assumed that exchange process is 100% efficient. 2) Calculate the equivalent weight of gypsum CaSO , 2H O 42 i.e. (40 + 32 + 64 + 4 + 32)/2 =172/2 = 86 g). WWDSE In Association with ICT Final FaasibH.'ty Suxjy RaponFederal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Dotall Design of Bale Gadula irrigation Project VOL 5-ANNEX 4 Soli Survey Study 83 3) imeq of gypsum i.e. 86/1000 = 0.086 g per 100 g of soil is required to replace 1 meq. of 1 NaX (where X is soil complex which adsorb the cations). 4) Calculate the mass of soil of 1 hectare area of furrow slice of 15 cm depth, which can be worked out by multiplying the volume of soil by its bulk density, as volume of soil is length x width x depth i.e. 100 x 100 x 100 x 100 x 15 = 15 x 10 cm The average bulk density of soil is 1 g cm-3 the mass of 1 ha - 15 cm. depth works out to 15 x 108 x 1.5 = 2.25 x 10g = 2.25 x 106 kg. 5) The amount of gypsum required replacing I meq of Na X per 100g of soil is as 100 gm. of soil requires the quantity of gypsum 0.086g. As 100g of soil requires the quantity of gypsum = 0.086g. Thus, 2.25 x 10 g of soil requires the quantity of gypsum = 0.086 x 2.25 x10 /100 g = 0.086X2.25 x10 /1000kg = 1935 kg /ha for 15 cm soil depth. 6) Field application efficiency of gypsum is about 1.25 x gypsum requirement. Thus the total quantity of gypsum required works out to 1935 x 1.25 kg. 7) Calculate the gypsum requirement to reduce the sodicity i.e. lowering of ESP Two aspects i.e CEC and ESP have to be taken in account. This can be understood by following example. However, this amendment measure is expensive it is better to use biological method by planting sodium resistant crop such as Rhodes grass, to improve gradually the permeability of the soil. Once permeability improved sodium ions can be leached from the soil with good quality water. 9 9 7 11.2.2 Addition of Organic Manures Incorporation of organic manures including farmyard manure, green manuring and addition of straw and crop residues in sodic lands facilitate the reclamation of sodic soils. Researches have shown that when farmyard manure is incorporated in soil with gypsum has higher beneficial effects. These help in the formation of organic acids, there by lowering of pH, release of cations, by solubilisation of WWDSE In Association with ICT Final Feasibility Study Report 99Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Projoct VOL 5-ANNEX 4 Soil Survey Study CaCO and other soil minerals, increasing the EC and replacement of 3 exchangeable Na by Ca & Mg and hence lowering the ESP. Highly dispersed sodic soils are devoid of soil organic matter and green manuring with Sesbania acueata in summer is helpful in reclaiming such soils. Green manuring add soil organic matter and increases soil fertility. The effectiveness of Sesbania acueata is due to the following characteristics: a) it is tolerant to salt and water logging conditions, b) its rooting system is extensive, c) it opens compact subsoil and improves soil permeability, d) its rate of decomposition is fast, and e) its cell sap is acidic and is capable of neutralizing the sodicity of the soil. Another method is deep ploughing, which can improve sodic soil where lime or gypsum is present at shallow depth in the soil. 11.2.3. Fertility In order to maintain soil fertility nutrients removed from the soil by crop must be restored by the application of fertilizers and manure. Even in a highly fertile soil reserve nutrient gets exhausted as crops are grown and harvested continually and needs replacement. To maintain organic carbon mulching of crop residues after harvesting should be practiced with application of manure and compost. The use of plant species that are capable of fixing atmospheric nitrogen can improve soil fertility and reduce dependency on chemical fertilizer. In addition improved agriculture practices such as crop rotation, alley cropping and the use of green manure provide accessory nutrient pool for plant growth. The application of organic matter also improves the CEC of the soil. Crop rotation is recommended, as it is essential for improving soil productivity. An alternate appropriate crop in accordance with a pre-established schedule help to keep the soils in good biological condition and to control the erosion risk, increase its water holding capacity, provides to take full advantage of fertilizer, prevent the unbalanced depletion of plant nutrients and counteract development of the toxic substances, if any. During the application of inorganic fertilizers balanced dose of macro-nutrient particularly NPK should be added in the form of fertilizers, but it has to be taking WWDSE In Association with ICT Final Feasibility Study RoportFederal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study into account the availability of nutrient already present in the soil, crop requirement and other factors. Supplying of optimum quantities of nutrient N, P and K with farm yard manure have beneficial effects on the physical and biological situations of the soils. In order to manage & maintain soil fertility in the project area organic manure and inorganic fertilizers should be utilized together. The application of nitrite containing fertilizers for crops grown under over head irrigated agriculture and water-logged soils, resulted in a considerable amount loss of N due to its denitrification. Therefore nitrogen fertilizers must be given split application depending on the critical growth stage of the crop. Application of green-manure increases utilization of phosphorus by the crop not from the added fertilizers but also from the reserve supplies of soil phosphorus. Application of K is made as a basal dressing through drilling, furrow application or broadcast before sowing or transplanting. Its application to perennial crops and fruits in trenches or spread in basin 32 cm away from the tree trunk can give better results. For foliar spray of K potassium sulphate and potassium can be recommended to avoid or minimize leaf scorching due to chloride. Sustainable soil management system, which include continuous crop cover, mulching, minimum tillage and organic maturing with appropriate inorganic fertilizers should be practiced in order to maintain and to improve soil fertility and to control soil erosion. 11.2.4 Soil Erosion Control The soils of the studied area are susceptible to erosion. It has been noted that there is the moderate to sever erosion hazard occurrence i.e. sheet, rill and gully erosion some sites of the project area. The risk of soil erosion is more considerable in the reddish brown clay soils of the project area occurring mainly on gently and undulating slopes due to its sloping nature and surface sealing property. WWDSE In Association with ICT Final Feasibility Study Roport 101Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study The anti-erosion measures should include agronomic and mechanical measures. The agronomic measures comprise contour farming, mulch, zero tillage, crop rotation, strip cropping and mixed cropping. These measures should be under taken on mild slopes up to 3-4%. The mechanical measures are physical structure such as graded bunding and bench terraces These measures should be deployed on higher slopes greater than 5% supplemented with agronomic measures especially on the surrounding hills of the command. Vegetation barriers) can also be planted on hill slopes at convenient distance and the terraces are formed gradually. The vegetation cover, occurring along the streams and the rivers should be maintained in order to avoid river bank erosion. 11.2.5 Leveling and Grading Generally the land in the project area is undulating, resulting into concave and convex topography due to presence of micro-relief such as termite mounds on well drained red soils and gilgai on Vertisols. During the field investigation moderate amount of termite mounds and in slight extent gilgai on Vertisols has been recognizes. Thus, land requires moderate grading and leveling. Termites attack plants and hence it is necessary to undertake control measures such as application of pesticides 11.2.6 Stone Removing Stoniness is a constraint for the project area especially in well drained reddish brown soils on gentle to undulating landforms such as Nitisols, Cambisols, Leptosols and Luvisols. Common to many stones and boulders are noted in some areas. Hence, stone picking should be carried out. WWDSE In Association with ICT Final Feasibility Study ReportFederal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study REFERENCE DEPSA/FAO, 1990, Collection and utilization of Land Resources Data for Feasibility Studies of Agricultural Development Project. Addis Ababa EVDSA/FAO, 1990, Bale-Gadula Medium Scale Irrigation Development Project Prefeasibility Study, Annex 1: Soils and Land Classification, Addis Ababa. FAO/ISRIC, 2006, World Reference Base for Soil Resources 2006 A framework for International Classification, correlation and Communication. FAO, 1990, Guide Lines For Soil Description Rome FAO, 1976; A Framework for Land Evaluation, Soil Bulletin No. 32, FAO, Rome. FAO, 1985; Land Evaluation for Irrigated Agriculture Soils Bulletin No. 32, , Rome FAO, 1979: Soil Investigation for Irrigation. ITC, 1999: Aerial Photo Interpretation for Soil Study. Landon J.R., 1991: Booker Tropical Soil Manual MoWR/Lahimayer, 2007, Genale-Dawa River Basin Integrated Resources Development Master Plan, Addis Ababa. MOWR/ Continental, 2001: Procedural Guidelines for Irrigation development; Soil survey and Land evaluation, Addis Ababa MCTD/ Demeke Lemma, 1987, Soils of Delomena-Bale, Physical and Chemical Conditions and their Suitability for Coffee cultivation. Raymond W. MillerS Roy L.Donahue, 1997, Soils in Our Environment, New Delhi Soil Survey Staff, 1993: Soil Survey Manual USDA-SCS. UNESCO, 1986: Guidelines for Soil Survey and Land Evaluation in Ecological Research. WWDSE In Association with ICT Final Feasibility Study Report 103Fedoral Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study APPENDIX Appendix I: Land and Soil Characteristics: Meaning and Classification Organic Carbon >24% : High Total Nitrogen <0.05% : Very low 1.5- 2.4% : Moderately high 0.05- 0.125% : Low 0.8 - 1.5% : Moderately low 0.125%-0.225% < 0 8 % : Low The quality of organic matter C/N <10 Good 10 -14 medium > 14 Poor 0.2255 - 0.30 >0.3 : Medium : High : Very high Source; Simple and practical Methods to Evaluate Analytical Data of Soil Profile Exchangeable Cations Ca Mg K Na Very high >20 >8 >1.2 >2.0 High 10-20 3-8 0.6-1.2 0.7-2.0 Medium 5-10 1.5-3 0.3-0.6 0.3-0.7 Low 22-5 0.5-1.5 0.1-0.3 0.1-0.3 very low <2 <0.5 <0.1 <0.1 Ca: Mg Ratio >40 Extremely high: over dose of Ca or lack of Mg. 12-40 Very high: reduction of available P if the PH is high too. 6-12 High: favorable. 3.5 - 6 Moderately high: very favorable. 2.5 - 3.5 Moderately low: Less favorable. 1.5 - 2.5 Low: not favorable. >1.5 Very low: severe Source: Simple and practical Methods to Evaluate Analytical Data of Soil Profile WWDSE In Association with ICT Final Feasibility Study ReportFederal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale GadulaJrrlgation^Prpjcct^^ VOL 5- ANNEX 4 Soil Survey Study Acidity and Alkalinity PH Rating <4.0 Extremely acidic 4 - 5.3 very acidic 5.3 -6.0 Moderately acidic Comments Only tea tolerates it. If present AL & Mn will be toxic. Ca, Mg & Mb may be deficient. The availability of P is low in the presence of free Al & Fe, Nitrification of O.M. P,Ca, Mg & Mb may be deficient, avoid fertilizers (ammonium sulfate and triple super phosphate), which may increase the acidity. 6.0-7.0 Slightly alkaline Fe may be deficient. Optimal availability of P. 7.0-8.5 Moderately alkaline Low available of P and micronutrients, with the exception of Mb. >8.5 Very alkaline Only few crops grow excess of Na, deficiency of P and micro nutrients, toxicity of Boron, Nitrification of O.M., and Ca may need correction. Cation Exchange Capacity and Base Saturation Rating >40 25-40 EC mmhos Very high High Comments Good agricultural soil As above but minor amendment is required 15-25 Medium Major amendment required 5-15 Low Moderate to poor response to fertilizer <5 Very low Poor agricultural land Source: Booker Tropical Soil Manual BSP (%) Available Phosphorus BSP Rating P(pmm) Rating Comments <20 Low fertility 15 High Fertilizer response unlikely 20-60 Medium fertility 5-15 Medium Fertilizer response probable >60 High fertility <5 Low Fertilizer response most likely Source: Booker Tropical Soi Manual WWDSE In Association with ICT Final Feasibility Study Report 105Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Baj^GadulaJrrigation^Projec^^ VOL 5-ANNEX 4 Soil Survey Study Carbonates Available Water Capacity Permeability Rating CaCO3 % Rating AWC(mm/m) Low <1 Low <20 HC(m/day) Rating Medium 1-4 Medium 120-180 <0.2 Very slow High 4-10 High >180 0.2-0.5 Slow Very high >10 0.5-1.4 Moderate 1.4-1.9 Moderately rapid 1.9-3.0 Rapid >3.00 Very rapid 'Source: FAO, 1979ve, Soil Survey investigation for Irrigation Approx. ESP Sodicity hazard 'Remarks ------------------------------------------------------------- ----- <15 None to slight The adverse effect of exchangeable sodium on ',15-30 Light to moderate the growth and yield of crops in various classes occurs according to the relative crop |30 - 50 Moderate to high tolerance to excess sodicity. Whereas the ',50 - 70 >70 High to very high Extremely high growth and yield of only sensitive crops are affected at ESP levels below 15, only extremely tolerant native grasses grow at ESP above 70 to 80 Source: FAO, Soil Bulletin 39, Salt affected soils and their management Soil salinity classes and crop growth Soil Salinity Class Non saline Slightly saline Conductivity Saturation (dS/m) [0-2 2-4 of the Extract Effect on Crop Plants Salinity effects negligible Yields of sensitive crops may be restricted Moderately saline [4-8 (Yields of many crops are restricted Strongly saline 18-16 Only tolerant crops yield satisfactorily Very strongly saline I*’6 Only a few very tolerant crops yield satisfactorily Source: FAO, Soil Bulletin 39, Salt affected soils and their management. Surface Stoniness Percentage Surface Cover by Stones and Rock Outcrops (from field and aerial photos) VWVDSE In Association with ICT Final Feasibility Study Report 106Federal Democratic Republic of Ethiopia- Ministry of Wator Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project 0% none 15-40% - many 0 -2 % - very few 40 - 80% - abundant 2 -5 % - few >80% - dominant 5-15% - common Infiltration Basic Infiltration: Suitability for Surface Irrigation Rate (cm/h) VOL 5-ANNEX 4 Soil Survey Study <0.1 - Unsuitable (too slow) but suitable for rice 0.1 -0.3 - Marginally suitable (too slow), marginally suitable for rice 0.3-0.7 - Suitable; unsuitable for rice 0.7 -3.5 - Optimum 3.5-6.5 - Suitable 6.5—12.5 - Marginally suitable (too rapid); small basins needed 12.5-25.0 - Suitable only under special conditions, very small basins needed >25 - Unsuitable (too rapid) overhead irrigation methods only Source: FAO, 1979ve, Soil Survey investigation for Irrigation WWDSE In Association with ICT Final Feasibility Study Report 107Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Balo Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study The FAO agro-ecological zones project in china has suggested flood classes for specific crop groups (Sys, 1990) as follows: Major flood class Rating General Description Specific Description F0 No flood limitations The land is higher than the highest water level No flooding F1 Slight The land surface is higher than the mean highest water level; however, occasional high floods may affect the land for a short period (not longer than 1-2 months) < 5 cm water for some days (2-3) F2 Moderate The land surface is at about the same level of the mean highest water level so that very often (more than 5 years out of 10) the land is flooded for a period of not longer than 2-3 months. < 5 cm water for less than one week F3 Severe The land surface is somewhat (20-30 cm) over than the mean highest water level, so that almost very year 20 to 30 cm floodwater occurs during a period of 2-4 months. < 10 cm water for less than one week F4 Very severe The land surface is much (more than 30cm) below the mean highest water level, so that nearly every year the land is flooded for more than 2 months and in most years for more than 4 months. > 10 cm water for more than 1 week WWDSE In Association with ICT Final Feasibility Study ReportJTJl-------- JU.. M I v - I 1 i . u Fodoral Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Balo Gadula Irrigation Project VOL 5- ANNEX 4 Soli Survey Study Appendix II:: Field Guideline Soil Survey Field Guide Line A. SITE Coverage >5% by steep sided gullies >2.5m DESCRIPTION G Gullied deep Strongly dissected areas with a drainage Major land form Gradient Relief intensity S Str. Dissected density Level land LP Plain LL Plateau % <8 of > 25km per km2; depth of drainage lines Dissecte Areas with a drainage density of between 10 <10 <100 m/km D d <8-10 <100 m/km and 25km Per km2; depth of drainage lines >2.5m. Slightly dissected areas with a drainage LT Plateau terrace <10 <100 m/km L SI dissected density of <10km LD Depression <10 <100 m/km Per km2; depth of drainage lines >2.5m. LF Low- gradient <8 <100 m/km LV Valley floor <8 <100 m/km Sloping land Rock type(for in situ weathered / saprolite only) /Lithology/ Medium-gradient Acid igneous SM mountain 15-30 >600m/2km IA rock i SC Schist Medium- G SH gradient hill 8-30 >50.m/slope unit R Granite MB Basic metamorphic rock D r\ SI Medium-gradient hillock 8-30 <50.m/slope unit H Rhyolite MR Marble WWDSE In Association with ICT Final Feasibility Study Report rut rFederal Democratic Republic of Ethiopia- Feasibility Study and Detail Design of Bale Gad Ministry of Water Resources VOL 5- ANN EX 4 ula Irrigation Projec t Soil Survey Study Medium-gradient escarpment P SE zone 15-30 <600m/2km U Pumice SE Sedimentary rock SR Ridge 10-30 >50m/slope unit TY Trachyte SA Sandstone Mountainous A 1 SU highland 10-30 >600m/2 km N Andesite CG Conglomerate SP Dissected plain 10-30 >50m/slope unit DI Diorite QS Quarizitic sandstone Basic igneous Steep land IB rock SI Siltstone kJG TM High-gradient mountain >30 <600m/2km A Gabbro MU Mudstone High-gradient TH hill >30 <600m/2km BT Basalt CL Clay stone High-gradient D TE escarpment >30 <600m/2km O Dolerite SH Shale High-gradient U TV valley >30 Variable B Ultra basic rock LI Limestone Composite land V ■ form O Volcanic rock DM Dolomite M Acid metamorphic CV Valley > 10 Variable A O rock ML Marl CL Narrow plateau > 10 Variable z Quartzite PY Pyroclastic rock WWDSE Jn Association with ICT Final Feas ibility Study Roport 110Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5- ANNEX 4 Soil Survey Study Major CD depression CT Rock tower Regional slope W 0-2 > 10 > 10 Variable Variable G N Gneiss G TU Tuff G Granite /Gneiss QU Quartz U Unknown % Flat, wet F 0-2 % Flat G 2-5 % Gently undulated, gently sloping U 5-8 % Undulating, sloping R 8-15 % Rolling, strongly sloping S 15-30 % Moderately steep T 30-60 % Steep V >60 % Very steep Composite classes e.g.: SL Slate Parent materials, unconsblidated (Faices) A Aeolian U deposits A S Aeolian sand L O Loess VA PY GL Volcanic ash Pyroclastic deposits Glacial deposits LI Littoral deposits OR Organic deposits L Lagunal G deposits M CO A Marine deposits WE LA Lacustrine deposits FL Fluvial deposits SA Colluvial deposits In situ weathered, residual Saprolite U Unknown WWDSE In Association with ICT Final Feasibility Study ReportFederal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5- ANNEX 4 Soil Survey Study FU 0-8 % Flat to undulating /sloping FG 0-5 % Flat to gently undulating/gently sloping GU 2-8 % Gently undulating to undulating / sloping Position H High Interluve, crest or higher part Upper and middle slope or any other medium Alluvial AL deposits Effective soil depth V Very shallow <25 cm S Shallow 25-50 cm Moderately 50-100 M deep cm 100-150 M medium position Lower slope or L Low lower part Depression, valley bottom or any other D Lowest lowest part Slope class D Deep Very cm X deep > 150 cm Rock out crops Surface cover (abundance) Distance Form of 01 Flat 0-0.2 % slope N None 0 % 1 >50 m 02 Level 0.2-0.5 % U Uniform V Very few 0-2 % 2 20-50 m 03 Nearly level 0.5-1.0 % C Concav F Few 2-5 % 3 5-20 m ■ ■■ ■ . ■ ________________________ ■■■ WWDSE In Association with ICT Final Feasibility Study Roport 112•I w Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5- ANNEX 4 Soil Survey Study Very gently 04 slope 1.0-2 % e 5- V Convex C Common 15 %1 4 2-5 m Irregula 15- 05 Gently slope 2-5 % Ir M Many 40 % 5 <2 m Terrace 40- 06 Sloping 5-8 % T d A Abundant 80 % 07 Strongly sloping 8-15 % D Dominant >80 % Moderately 08 steep 15-30 % Surface coarse 09 Steep 30-60 % fragments 10 Very steep >60 % Local surface form LE Level Micro- relief produced by expansion and Surface cover (abundance): Classes as for Rock outcrops Size Fine Gl Gilgai contraction of montmorillonitic clay with changes in F gravel M Medium gravel 0.2-0.6 0.6-2 cm cm moisture; found in C Coarse gravel Vertisols; in nearly level areas a succession of S Stones 2-6 6-20 cm cm WWDSE In Association with ICT Final Feasibility Study Report r TT I • IFederal Democratic Republic of Ethiopia* Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5- ANNEX 4 Soil Survey Study micro basins and micro-knolls; on sloping and micro-valleys B Boulders 20-60 cm and micro- ridges parallel to the direction of the slope. L Large boulders 60 - 200 cm F Fine and medium GL Low gilgai Height difference (with 10m) <20 cm M gravel FC Fine to coarse gravel Height difference (with 10m) 20-40 M Medium and coarse GM Medium gilga! cm C gravel SB Stones and boulders GH High gilgai Height difference (with 10m) >40 cm Types of erosion AT Animal tracks Termite or ant /deposition No visibe evidence of Deposition by TM mounds N erosion P water Riverbank Water & wind AB Animal burrows B erosion W erosion Meso-relief (2.5-2.5m) showing a very H Hummocks complex pattern of C Undercutting L Wind deposition slopes, extending from some what rounded Sheet and splash Wind erosion & depressions of various S erosion A deposition Rill Sizes to irregular conical knolls or knobs. R erosion D Shifting sand WWDSE In Association with ICT Final Feasibility Study Roport 114Federal Democratic Ropubllc of Ethiopia- Ministry of Wator Resources VOL 5- ANNEX 4 Feasibility Study and Detail Doslgn of Balo Gadula Irrigation Projoct Soil Survey Study Coverage at least 5 & by parallel, sub parallel, Ridges or intersecting G Gully erosio n Z Salt deposition usually sharp- crested ridges or elongated narrow elevations T Tunnel eros ion U Unknown More than 2.5m high. Coverage at least 5% by isolated steep sided Towers karst towers Area affected Activity Active at more than 2.5m high 1 0-5% A present Level areas <2% slope bounded on one side Active in re cent Terraced by a steep slope 2 5-10% R past >2.5m high with another flat surface above it. 3 10-25% H Active in hi storical times Period of activity 4 25-50 % U unknown 5 > 50 % X Accelerate d & nat ural erosi on not distinguish WWDSE In Association with ICT Final Feasibility Study ReportFederal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study 1 J ] 3 J ] 3 1 3 3 3 3 3 1 1 1 1 Order Group System Settlement/lndustries (S) Residential use (SR) Industrial use (SI) Transport (ST) Excavation (SE) Cultivation (C) Annual field cropping (CA) Shifting cultivation (CA1) Fallow system cultivation (CA2) Ley system cultivation (CA3) Rain fed arable cultivation (CA4) Wet rice cultivation (CA5) Irrigated cultivation (CA6) Perennial field cropping (AP) Non-irrigated (CP1) Irrigated (CP2) Tree & shrub cropping (AT) Non-irrigated tree crop cultivation (CT1) Irrigated tree crop cultivation (CT2) Non-irrigated shrub crop cultivation ( CT3) Irrigated shrub crop cultivation (CT4) Animal Husbandry (H) Extensive grazing/browsing (HE) Nomadic (HE1) Semi-nomadic (HE2) Ranching (HE3) Intensive grazing (HI) Animal production (H11) Dairying (HI2) Forestry (F) Exploitation of natural forest & woodland (FN) Selectively felling (FN1) Clear felling (FN2) Plantation forestry (FP) Mixed farming (M) Agro-forestry (MF) Agro-pastoralist (Cropping & livestock systems) (MP) Extraction/Collection (E) Exploitation of natural vegetation Timber production (EV1) Wood collection (EV2) Charcoal production (EV3) Hunting and fishing (EH) Nature protection (P) Nature & game Preservation (PN) Reserves (PN1) Parks (PN2) Wildlife management2PN3)___ Degradation control (PD) Non-interference (PD1) With interference (PD2) UNUSED (U) Others (specify) Others (specify) Order Group System Settlement/lndustries (S) Residential use (SR) Industrial use (SI) Transport (ST) Excavation (SE) Cultivation (C) Annual field cropping (CA) Shifting cultivation (CA1) Fallow system cultivation (CA2) Ley system cultivation (CA3) Rain fed arable cultivation (CA4) Wet rice cultivation (CA5) Irrigated cultivation (CA6) Perennial field cropping (AP) Non-irrigated (CP1) Irrigated (CP2) WWDSE In Association with ICT Final Feasibility Study Report 116Federal Democratic Republic of Ethiopia- Ministry of Water Resources ^easn3Hlty Studyjind Detail Design of Bale Gadula Irrigation Project VOL 5- ANNEX 4 Soil Survey Study Animal Husbandry (H) Extensive grazing/browsing (HE) Nomadic (HE1) Semi-nomadic (HE2) Ranching (HE3) Intensive grazing (HI) Animal production (HI1) Dairying (HI2) Forestry (F) Exploitation of natural forest & woodland (FN) Selectively felling (FN1) Clear felling (FN2) Plantation forestry (FP) Mixed farming (M) Agro-forestry (MF) Agro-pastoralist (Cropping & livestock systems) (MP) Extraction/Collection (E) Exploitation of natural vegetation Timber production (EV1) Wood collection (EV2) Charcoal production (EV3) Hunting and fishing (EH) Nature protection (P) Nature & game Preservation (PN) Reserves (PN1) Parks (PN2) Wildlife management (PN3) Degradation control (PD) Non-interference (PD1) With interference (PD2) UNUSED (U) Others (specify) Others (specify) WWDSE in Association with ICT Final Feasibility Study Report 117Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Balo Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study Land Covers 1 Major Classes Land Cover type Mapping units 1 Settlement/lndustries S/l [ Cultivated lands CL State farm CL1 Intensively cultivated land CL2 Predominantly cultivated CL3 Moderately cultivated land CL4 Sparsely cultivated CL5 Perennial crop cultivation CL6 1 Afro-Alpine and Sub- Alpine vegetation AA Forestlands FL Dense coniferous high forest FL1 Dense mixed high forest FL2 Disturbed high forest FL3 1 Woodlands WL Dense woodland WL1 Open woodland WL2 | Riparian wood lands or Bush lands RL 1 Bush land BL Dense bush land BL1 Open bush land BL2 Shrub lands SL Dense shrub land SL1 Open shrub land SL2 Grass lands GL Open Grass land GL1 Bushed shrub grass land GL2 Wood grass land GL3 Wet lands WE Perennial swamp WE1 Perennial marsh WE2 Seasonal swamp WE3 Seasonal marsh WE4 Bare lands BA Exposed rock surface BA1 Salt flats BA2 Exposed sand and soil surface BA3 Exposed sand and soil surface with scattered scrub and grass BA4 Water body | Other (specify) WB WWDSE In Association with ICT Final Feasibility Study Report 118Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Projoct Appendix III: Format for Data Collection VOL 5- ANNEX 4 Soil Survey Study BALE-GADULA, BALE-GADULA & BALE-GADULA IRRIGATION PROJECT SOIL PROFILE PIT & SITE DESCRIPTION SHEET PROFILE/CODE STATUS............ DATE............. AUTHOR.............. REGION............. ZONE.............. WOREDA............ LOCATION.................. ELEVATION (AM)............. GPS.............. MAP SHEET NO UTM N.............. UTM E............. MAJOR SOIL TYPE FAO 98............. PHASE..................... AGR CLIM ZONE....................... RELIEF INTENSITY............../ /............. m/.km. si un LANDFORM REGIONAL SLOPE................. DISSECTION........... POSTION.................................. SLOPE ASPECT........................ MICROTOPOGRAPHY............... HIGHT................M COVERAGE........................... SLOPE CLASS....................... SLOPE LENGTH....................... SLOPE FORM......................... PARENT MATERIAL........ OVER........... EFFECTIVE SOIL DEPTH ROCK OUTCROP DEPTH TO BED ROCK SRF.CORSE FRAGMENTS: COVER/SIZE................./......... SURF.CRACK SEALING ... DRAINAGE:CLASS/EXT./ENT............... /......../ ..../ WATER :OBS/MIN/MAX............. /.......... /........../ TABLE FLOODING:FREQ/DUR.......... J........ MOIT.COND......... /........ EROSION STATUS: T....... /A........ /AC......./D............ FERTILIZER TYPE/RATE............ /......... LAND COVER*............... / ........ /........../............. /... LAND USE.................. CROP... ............. /........... /............ /.......... Plant Species REMARKS----------------------------------------------------------------------------------------------------------------------------- WWDSE In Association with ICT Final Feasibility Study Report 119Federal Democratic Republic of Ethiopia- Ministry of Wator Resources Feasibility Study and Detail Design^£Bajc GadulaJrrigation^f2|22^M VOL 5-ANNEX 4 Soil Survey Study BALE-GADULA, BALE-GADULA & BALE-GADULA IRRIGATION PROJECT SOIL PROFILE PIT &SITE DESCRIPTION SHEET PROFILE/ CODE CONSISTENCY HORI ZON Diagn ostic DP T Up Io w BN D d COLOUR MOTT LE TEXT URE ROC KER STRUCT URE dr y mo ist wel hu e val c hr m 0 a co <2M M a s i 9 si t y si t Pl a YR YR D M YR YR D M YR YR D M YR YR D M YR YR D M ___ ____ YR YR D M YR YR D M YR YR D M CUTANS CEM/COMP NODULES ROOTS BIOL a c na gs na a co h na k a si a k PORES a si Ca Co3 PH ____ 1 REMARKS: na = nature sti = stickiness c = contrast co = colour d = distinctness = hardness = kind s = structure pla = plasticity ty = type mo = moist(ure cond si = size WWDSE In Association with ICT Final Feasibility Study Report 120Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5- ANNEX 4 Soil Survey Study . BALE-GADULA, BALE-GADULA & BALE-GADULA IRRIGATION PROJECT SOIL PROFILE PIT &SITE DESCRIPTION SHEET AUGER CODE STATUS............ AUTHOR.............. DATE............. REGION.............. ZONE............ WOREDA............ LOCATION.................. ELEVATION (AM)............. GPS.............. MAP SHEET UTM N.............. UTM E.............. MAJOR SOIL TYPE FAO 98............. PHASE..................... AGRCLIM ZONE........................ RELIEF INTENSITY.............. / / .... m/.km. si un LANDFORM REGIONAL SLOPE.................. DISSECTION............ POSTION.................... SLOPE ASPECT........................ MICROTOPOGRAPHY................... HIGHT................ M COVERAGE........................... SLOPE CLASS....................... SLOPE LENGTH........... SLOPE FORM......................... PARENT MATERIAL.........OVER........... EFFECTIVE SOIL DEPTH .................. ROCK OUTCROP...................... DEPTH TO BED ROCK SRF.CORSE FRAGMENTS: COVER/SIZE................. /............. SURF.CRACK SEALING ... DRAINAGE:CLASS/EXT./ENT................/......../ ..../ WATER :OBS/MIN/MAX............. /.......... /.......... / TABLE FLOODING:FREQ/DUR............ /... MOIT.COND......... /........ EROSION STATUS: T....... /A........ /AC....... /D............ FERTILIZER TYPE/RATE............ /......... LAND COVER*.............. / ......... /.......... /............. /... LAND USE.................. CROP... ............. /........... /............ /.......... ♦ Plant Species REMARKS------------------------------------------------------------------------------------------------------------------------- WWDSE In Association with ICT Final Feasibility Study Report 121Federal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula lrrigatjonj*roject^^^^^^^^ BALE-GADULA, BALE-GADULA & BALE-GADULA IRRIGATION SOIL PROFILE PIT &SITE DESCRIPTION SHEET AUGER CODE VOL 5- ANNEX 4 Soil Survey Study HORI ZON Diago nostic DPT Upp low BND d COLOUR MOTTLE TEXTU RE ROCKFR GEMENT hue val chr 1 mo a co <2MM a si YR 4 YR :D :M YR YR :D :M YR YR :D :M YR YR :D iM. YR YR :D ;m YR YR ;D :M - YR YR •D :M YR YR :D ;m CEM/COMP NODULES Ca C03 PH Ec g Is | na a co | h na k :-------------------------------------- :-------------------- 1• I 1I • 1 • » 1• 1 « • 1 1• • • t • » • 1 •• «• 1 < •• REMARKS: a = abundance g = grade h = hardness k = kind na - nature mo = moist co = colour si = size WWDSE In Association with ICT Final Feasibility Study ReportFederal Democratic Republic of Ethiopia- Ministry of Water Resources Feasibility Study and Detail Design of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soil Survey Study Bale-Gadula, Bale-Gadula & Bale-Gadula Irrigation Projects Soil lie Conductivity Test Measurement Form IL Profile no. Date : Author:- Surface features:- UTM Reading N: E: ---------- r (r Water source: Pre wetting : Average Rate (m/day) II Rep.no. 1 Radius(cm): Rep.no.2 Radius(cm): Rep.no.3 Radius(cm): Depth (cm): Depth (cm): Depth (cm): :n ti h'(t') h’(t') h(ti)+r/2 ti h'(t') h’(f) h(ti)+r/2 ti h'(f) h'(t') h(ti)+r/2 (sec) cm cm cm (sec) cm cm cm (sec) cm cm cm f L r r L s 7 Conductivity m/day Conductivity m/day Conductivity m/day | Average Rate (m/day) m/day L K= 1.15r Log(h(t, +r/2)- } Log(h(tn)-*-r/2) tn - t WWDSE In Association with ICT Final Feasibility Study ReportFederal Democratic Ropublic of Ethiopia- Ministry of Water Resources Feasibility Study and Dotall Design of Bale Gadula Irrigation Project VOL 5-ANNEX 4 Soli Survey Study Bale-Gadula, Bale-Gadula & Bale-Gadula Irrigation Projects [ Soil Infiltration Rate Measurement Form Profile no. Date:- Replication Author: Surface feature: - UTM Reading N: E: Local Interval (min) Cumulative time (min) Depth of Water(cm) Intake (cm) Infiltration rate (cm/hr) Initial Final Cumulative Intake (cm) Immediate Mean • • - WWDSE In Association with ICT Final Feasibility Study Report 124RESERVEDRESERVED
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