The Effects of Various Land Use Types on Particular Physicochemical Characteristics of the Soil in Mante Watershed, South Regional Government of Ethiopia

Abstract

Soil quality is threatened when the forest cover is replaced by cultivated and grazing lands in Mante watershed found in South Ethiopia. The study aimed to ascertain how different land use patterns and slope gradients affected the physicochemical characteristics of the soil. The watershed was stratified according to the predominant land use types, namely, grazing land, cultivated land, and forest lands with slope gradient variations to choose sites for soil sampling. Three slope classes were used to categorize the catchments of the watershed: 0–15%, 15–30%, and >30%. In soil depths of 0–20 cm and 20–40 cm, fifty-four (54) composite soil samples were taken (3 land use types × 3 slope classes × 2 soil depths × 3 replications). The results showed that the highest mean values of total nitrogen, available phosphorus, CEC, Ca, K, Mg, and Na were high but pH was low under forest lands and slope gradients of >30% but cultivated lands with the lowest mean values found in the range of 0–15% slopes. Regarding soil depth, the upper layer (0–20 cm) had higher mean values for silt fraction, pH, CEC, and Mg, while the lower layer (20–40 cm) had lower mean values. The soil quality was higher under the forests because Na had a greater significance in the upper soil layer and a lower value in the lower soil layer. The decline in the soil quality under the cultivated land suggests that integrated soil and water management is necessary to maintain the favorable soil physicochemical properties and replenish the degraded soil.