Abstract
<title>Abstract</title> <p>Land degradation severely threatens agricultural productivity in the Ethiopian drylands. While physical soil and water conservation (SWC) structures, such as stone bunds, have been widely implemented, their long-term impact on soil fertility remains inadequately quantified. This study evaluated the effects of stone bund duration (0, 5, 10, 15, and 20 years), slope position, and soil depth on soil physico-chemical properties in the Abreha we Atsebha watershed, Northern Ethiopia. A 5×3×3×2 factorial arrangement in a randomized complete block design was employed, with 180 soil samples analyzed for parameters including bulk density, soil moisture, total nitrogen, and available phosphorus. Results revealed that soil quality improvements were positively correlated with the duration of conservation. Farmlands managed with 20-year-old structures exhibited the most favorable fertility indicators, including reduced bulk density, enhanced organic carbon, and higher nutrient availability. Significant interaction effects were observed between SWC duration, slope position, and soil depth, indicating that the efficacy of stone bunds is landscape-dependent and creates distinct vertical nutrient stratification. These findings demonstrate that long-term SWC measures are transformative for soil restoration, though their physical benefits are constrained by geomorphic site conditions. We conclude that sustaining agricultural productivity in semi-arid regions requires a shift toward landscape-responsive conservation strategies and depth-integrated soil monitoring protocols to optimize long-term nutrient recovery.</p>