Effects of different land use types on soil characteristics and surface acidity in Sidama Region, Southern Ethiopia

Converting forests and grasslands to farms can impact soil properties and increase acidity. This study examines the effects of various land use types (LUTs) (cultivated, grazing, and forest) on soil characteristics and surface acidity in the Hula and Gorche districts of southern Ethiopia, analyzing 72 soil samples from six villages. The LUTs significantly influenced (p < 0.05) soil properties and acidity. Cultivated and grazing lands had higher sand content, bulk density, and levels of exchangeable acidity (EA) and acid saturation, but lower exchangeable bases and percent base saturation (PBS) compared to forest lands. In contrast, forest land had greater clay content, lower bulk density, and higher pH levels, indicating milder acidity. Total nitrogen and available phosphorus were also found to be lower in these areas. Soil organic carbon (SOC) levels were moderate in cultivated and grazing lands but high in forested regions. Significant correlations were identified in the chemical properties of the soil. Variations in soil SOC, cation exchange capacity, and PBS likely explain the differences in acid-buffering capacity across various land uses. The increased EA and lower pH in cultivated lands may enhance the availability of micronutrients, with soil acidity being a key factor that affects land use and micronutrient levels. The study recommends integrated strategies, including forest trees that enhance soil fertility and optimal agronomic practices, to manage soil acidity and fertility, aiming to increase crop productivity in regions facing similar challenges.