The Effects of Land Use Types and Soil Depths on Soil Micronutrients, Soil pH, and Organic Carbon in Southern Ethiopia

Abstract

Soil micronutrients are vital for the enhancement of soil and crop productivity. Its deficiency can result in severe crop failure. Hence, exploring the status of soil micronutrients under different land use types and soil depths is crucial. This study investigated the effects of land use type and soil depth on soil micronutrients, soil pH, and organic carbon in the Buno Kebele of southern Ethiopia. For this study, four replicate quadrat plots (100 m2) were prepared for each land use type. A total of 24 soil samples were taken using an auger from three land use types (cultivated land, agroforestry land, and grazing land) at two depths (0–20 and 20–40 cm). Soil micronutrients (Zn, Fe, Mn, and Cu) were measured using the diethylene triamine pentaacetic acid (DTPA) method. Moreover, two-way analysis of variance (ANOVA) using SAS software (version 9.4) was used to analyze the effects of land use type and soil depth on soil nutrients. The results revealed that soil micronutrients (Zn, Fe, Mn, and Cu), soil organic carbon (SOC) and soil pH were significantly affected by land use type, soil depth and their interaction. Besides, soil micronutrients had a negative relationship with soil pH, whereas SOC significantly and positively correlated with soil micronutrients. Soil micronutrients and SOC increased with decreasing soil depth in all land use types. In addition, soil micronutrients and SOC were higher in agroforestry land use than in grazing and cultivated land use types. Therefore, agroforestry-based agricultural practices provide invaluable evidence for policymakers and should be promoted to implement effective soil nutrient management strategies and to realize sustainable agricultural productivity to ensure food security.