EFFECT OF CLIMATE SMART SOIL AND WATER CONSERVATION PRACTICES AND SLOPE GRADIENT ON SELECTED SOIL PHYSICOCHEMICAL PROPERTIES AND SOIL ORGANIC CARBON STOCK IN KULKULEYSA SUBWATERSHED OF GORO

This study was carried out in Kulkullessa Sub-Watershed of Goro Gutu District in Eastern Ethiopia to assess the effects of climate smart SWC practices and slope gradient on selected physicochemical properties of the soil and the soil's organic carbon stocks. The farmland conserved by SB, BT and GS five years after construction with two slope gradients (15-20%) and (21-30%) was selected. Twenty-four composite soil samples were collected from a depth of 20 cm and tested in the Haramaya University soil laboratory. The result was analyzed with the statistical software SPSS Version 20. The study found that climate smart SWC practices were very effective on soil physicochemical properties and SOCS of the study area. Similarly, the slope gradient was brought considerable variation on soil physicochemical properties and soil organic carbon stock. More amount of clay and lower sand were recorded on conserved farmland and situated on lower slope gradient. The lower value of BD was recorded on farmland conserved by bench terrace. The recorded value for total porosity on the farmland conserved by BT was also positively higher and significant (p ≤ 0.05). The higher value for EC and lower pH value were recorded on conserved farmlands, which were significant (p ≤ 0.05). In addition, SOM content and TN were exhibited highest values on the farmland conserved by stone bund. Further, climate smart SWC practices were found effective on increasing the value of exchangeable bases on farmlands of the study area. In addition, CEC has been positively influenced and significant (p ≤ 0.05) on farmland conserved by SB and bench terrace. Likewise, the higher mean values for micronutrients and SOCS were recorded on farmlands conserved by SB, BT and GS in contrast to the value recorded on NCF of the study area. In general, climate smart SWC practices were resulted in outstanding potential for improving the agriculturally and environmentally sound physicochemical properties of the soil and organic carbon stock