Variation in Soil Physico-Chemical Properties Driven by Land Use Change in Acidic Soils of Southern Ethiopia

Acidic soils are extensively cultivated in the Ethiopian highlands. Due to low fertility, these soils are experiencing rapid changes in land use. It is important to quantify the magnitude of changes in soil properties and implications to agricultural sustainability. With the aim to evaluate the effect of different land uses on soil properties, soil samples were collected from three land uses on Chromic Lixisols (Clayic): cultivated land, grazing land, and eucalyptus plantation. Eucalyptus plantation was converted from grazing land 15-20 years ago. Cultivated land had the lowest sand, soil organic carbon (SOC), and total N contents, while exhibiting the highest levels of silt, clay, and exchangeable bases. Cultivated land showed the highest bulk density in the 0-20 and 20-40 cm depths. The lowest soil pH was observed under eucalyptus plantation. Grazing land had the lowest available P. Cation exchange capacity (CEC) and carbon-to-nitrogen (C : N) ratio remained consistent across all land uses. Conversion of grazing land to eucalyptus plantation resulted in a reduction of soil pH by 0.55 units (p = 0.016) and a 13.4% increase in available P (p = 0.003), but resulted in non-significant variations in SOC, total N, and exchangeable bases. Our findings underscore the necessity for implementing appropriate soil management strategies to mitigate SOC and topsoil loss under cultivated land. Based on the results, eucalyptus plantation may not affect sustainability in terms of nutrient depletion in these soils in the short term.