Characterization of soils of cotton growing areas of arba minch zuria woreda, gamo gofa zone, southern Ethiopia

There is an enormous potential for the production of cotton in Ethiopia, given the suitable agro-ecological conditions in certain regions. However, with small area and low productivity, the country has insignificant gains from its cotton production. Soil-related constraints could be one of the factors for low cotton productivity. Presently, little information is available to farmers and extension workers on different aspects of soil management in the cotton growing areas of Ethiopia, in general, and Arba Minch Zuria Woreda in particular. To substantiate the information, 30 composite surface soil samples representing different sites in three kebeles (ZeyseElgo, Genta Kanchama, Shelle Mella) of woreda, were analysed for different physico-chemical properties. The texture of soils varied from silty loam to silty clay loam, the bulk density from 1.25 to 1.55 Mg m-3 and porosity from 39.2 to 47.9 %. While the soils of Genta Kanchama were moderately alkaline (pH 8.2), the soils of ZeyseElgo and Shelle Mella were strongly alkaline (pH 8.9 and 9.1). The soils of Genta Kanchama and Shelle Mellakebeles with EC of 4.5 and 9.0 dSm-1, respectively were affected by soil salinity. All soils had very high concentrations of exchangeable Ca and Mg, contributing almost fully to the total base saturation. The CEC of soils varying from 38 to 55.10 cmol(+) kg-1 was high. The organic carbon content of 1.2 to 1.7 % was low to medium. The total N status of the soils was medium with its content varying from 0.13 – 0.19%. The available P of 12.7 to 47.0 mg kg-1 was medium to high. With high exchangeable K, all the kebele soils were adequately supplied with potassium. The contents of available micronutrients viz., Fe, Mn and Cu were sufficiently high in all the soils. The concentration of Zn was, however, at a critical level. For sustained cotton production in the area, the soil management would include control measures for the salinity-affected soils and addition of nitrogenous and zinc fertilizers and organic manure on all the soils.