Effects of land use types on soil quality dynamics in a tropical sub-humid ecosystem, western Ethiopia

Abstract

Soil quality degrades when natural forests are converted to human-managed ecosystems. Limited empirical evidence of such soil quality changes has been observed in tropical sub-humid ecosystems. This study aimed to analyze the impact of land use change on soil quality dynamics in a tropical sub-humid ecosystem in western Ethiopia. To analyze some impacts, 80 composite soil samples (0–20 cm depth) and 45 undisturbed soil samples (0–7 cm depth) were collected from different land use patterns, including natural forests, grasslands, recently developed commercial lands, old commercial farmlands, and smallholder cultivated farmlands. A one-way analysis of variance (ANOVA) was performed to determine the effect of different land uses on soil quality indicators. The soil quality index (SQI) was used to evaluate the impact of land use on selected soil quality indicators, using the weighted additive SQI method derived from Principal Component Analysis (PCA). Our results showed that certain soil quality indicators, such as soil organic matter, total nitrogen, bulk density, porosity, cation exchange capacity, exchangeable calcium, and magnesium, were significantly degraded when compared to forest soils as a benchmark (at significance levels of P < 0.05, 0.01, and 0.001). Our study concluded that soil organic matter content, pH, field capacity, exchangeable calcium and potassium, available phosphorus, and bulk density could be used as key SQI assessment attributes in tropical sub-humid ecosystems and similar environments. Sustainable land management practices are crucial in enhancing soil quality indicators across different land use systems in tropical sub-humid ecosystems.