Effects of Soil and Water Conservation Practices and Slope Gradients on Selected Soil Physicochemical Properties and Technical Fitness of Physical Structures; in Ijara Watershed, Nonno District, West Shewa, Ethiopia.

Abstract

Ethiopia; is one of the country in eastern Africa, which is highly threatened by soil degradation problems caused by erosion. Physical soil and water conservation (PSWC) practices are one of the mechanisms implemented to reduce soil erosion and associated nutrient loss. However, not enough studies have been so far conducted in the study area. Therefore, this study was conducted to evaluate the effects of physical SWC structure and slope gradients on selected physicochemical properties of soil and the technical fitness of implemented PSWC structures in the Ijara watershed in Nonno district, West Shewa, Ethiopia. The research employed Randomized Complete Block Design. A total of 18 composite soil samples were collected from the top 20 cm of soil depth from farmland under SWC and without SWC structures at three landscape positions. The collected soil was analyzed in the Ambo University chemistry laboratory. The data were statistically tested using SPSS version 25 software. The results showed that sand particles, clay particles, moisture, Soil Organic Matter, Soil Organic Carbon, Cation Exchange Capacity, Total Nitrogen, and Exchangeable Calcium and Potassium were significantly (p<0.05)due to the conservation practice. Bulk Density, Moisture Content, Electro Conductivity, CEC, Total Nitrogen, and Exchangeable Potassium and Magnesium showed a significant (p<0.05) variation related to slope gradients. Except sand particles and BD, all the analyzed soil properties’ mean values increased from the upper to the lower slope. The technical fitness of the implemented stone bunds’ dimensions (length, spacing, height, top width, and bottom width) exceeded the recommended standard for each slope gradient. In the study area, the stone bund structures of the watershed can reduce soil erosion problems and have desirable effects on soil physicochemical properties, which in turn improve the productive capacity of the land. Further studies should be needed on others soil physicochemical properties and farmers’ perception on SWC for better management of watershed.