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.
