Land Use Land Cover Change and Its Effect on Selected Soil Physico-Chemical Properties in Southwest Ethiopia

Abstract

Land cover transformation exerts adverse effects on the environment. This study examined the changes in land cover in the Semen Bench District of southwest Ethiopia from 1986 to 2018, as well as its implications for soil physico-chemical properties. A mixed-method approach was employed, integrating remote sensing (RS) and geospatial data with soil physico-chemical analysis and key informant interviews. Landsat images were processed using ERDAS IMAGINE 2015, and the land use land cover (LU/LC) map was classified using a supervised method employing the maximum likelihood classifier (MLC) algorithm. The classification accuracy was 90%, 87.5%, and 90% for the years 1986, 2001, and 2018, respectively, with corresponding kappa coefficients of 0.87, 0.83, and 0.87. One-way analysis of variance (ANOVA) was conducted to assess differences in soil parameters across various land uses, utilizing SAS software (Version 9.3). The findings indicated that agroforestry and settlements increased by 95% and 428.7%, respectively, while forestland and cropland decreased by 38.6% and 96%, respectively, primarily driven by the expansion of cash crops such as coffee, khat, and eucalyptus, as well as population growth. Significant changes (P<0.05) were observed in soil bulk density, soil organic matter, soil pH, available phosphorus, total nitrogen, exchangeable cations, cation exchange capacity, and electrical conductivity, due to land cover change. Conversely, soil texture remained unaffected (P>0.05) by these transformations. Consequently, it is essential to develop sustainable natural resource management plans to combat deforestation and the decline in soil fertility.