Effects of Land Use Types on Surface Soil Acidity in the Highlands of Sidama, Ethiopia: Implications for Sustainable Land Management

Unsustainable land uses substantially alter soil properties, exacerbating soil acidification, threatening soil fertility, and impacting crop productivity globally, including in Ethiopia. Hence, assessing the impacts of various land use types (LUTs) on soil characteristics is imperative for the implementation of sustainable land management. A total of 60 soil samples were taken from two districts (Gorche and Hula) to evaluate the status of surface soil acidity across three LUTs: home garden agroforestry, Eucalyptus plantations (EPs), and fallow lands. Results indicated that the LUTs significantly (p < 0.05) influenced all measured soil properties. Soils under EPs were strongly acidic, consistently exhibiting higher exchangeable acidity (EA) and acid saturation (AS%). In addition, these LUTs had lower soil OC, total N, available P, and CEC contents. In contrast, home garden LUTs maintained higher pH, soil OC, total N, available P, CEC, and PBS while displaying lower EA and AS%, in comparison with EP and fallow LUTs. Fallow lands displayed moderately acidic conditions. The findings have implications for the importance of home garden agroforestry in restoring soil health for environmental and agricultural sustainability. Hence, the study suggests prioritizing these LUTs and replacing EP lands with native trees like bamboo, Hagenia abyssinica, Erythrina abyssinica, and others, which can enhance soil fertility. To improve soil fertility on fallow lands, the study advises implementing suitable soil and water conservation practices that can reduce soil erosion and increase the hydraulic conductivity of soils in these LUTs. In conclusion, these strategies may substantially help mitigate land degradation, restore productivity, and ensure long-term sustainability.