Impacts of climate-smart soil and water conservation practices and slope gradient on selected soil chemical properties in Eastern Ethiopia: A case study of the Kulkullessa Sub-watershed, Goro Gutu District

Abstract

The productivity and sustainability of agricultural systems are heavily influenced by soil fertility and physicochemical properties. This study investigated the effects of climate-smart soil and water conservation (SWC) practices and slope gradient on selected soil physicochemical properties and soil organic carbon stock (SOCS) in the Kulkullessa Sub-Watershed of Goro Gutu District, Eastern Ethiopia. The research focused on farmland conserved by stone bunds (SB), bench terraces (BT), and grass strips (GS) five years post-implementation, across two slope gradients (15-20% and 21-30%). Twenty-four composite soil samples were collected from a depth of 0-20 cm and analyzed at the Haramaya University soil laboratory. Results demonstrated that climate-smart SWC practices significantly improved soil physicochemical properties and SOCS in the study area. Slope gradients also induced considerable variations in these parameters. Conserved farmland and areas with lower slope gradients exhibited higher clay content and lower sand fractions. Bench terraces were associated with lower bulk density (BD) and significantly higher total porosity (p ≤ 0.05). Conserved farmlands showed higher electrical conductivity (EC) and lower pH values, both statistically significant (p ≤ 0.05). Stone bunds were most effective in increasing soil organic matter (SOM) content and total nitrogen (TN). Climate-smart SWC practices also enhanced exchangeable bases in the farmlands. Cation exchange capacity (CEC) was significantly improved (p ≤ 0.05) on farmland conserved by SB and BT. In conclusion, climate-smart SWC practices demonstrated substantial potential for improving agriculturally and environmentally relevant soil physicochemical properties and organic carbon stocks. These findings underscore the importance of such conservation measures in enhancing soil quality and promoting sustainable agriculture in the region.

Keywords

• adaptation
• climate-smart agriculture
• micronutrients
• mitigation
• soil properties