Effect of land-use types and topographic positions on soil physico-chemical properties in urago and mendi micro-watersheds, Becho District, Central Highlands of Ethiopia

Abstract

Watershed-scale management practices (WMPs) aimed at mitigating land degradation from soil erosion have been implemented across Ethiopia, including in the study area, yet their effect remains under-evaluated. A useful method to assess the effect of WMPs involves comparing soil characteristics between micro-watersheds subjected to different treatments. For this analysis, the Urago and Mende micro-watersheds in Becho district, central Ethiopia, were chosen for their similar physical attributes, though only Urago received government-initiated WMP interventions. This study aims to assess the effect of WMPs on soil properties under varying land use types (LUTs) and topographic positions (TPs) in conserved versus non-conserved areas. To achieve this objective, soil samples were systematically collected from three distinct LUTs at upper, middle, and lower TPs in both conserved (Urago) and non-conserved (Mende) micro-watersheds. The analysis of soil properties across different micro-watersheds revealed no significant differences. However, there were indications of minor improvements in soil organic carbon (SOC), total nitrogen (TN), and percent base saturation (PBS) in the conserved micro-watershed. These improvements are likely attributable to interventions such as stone and soil bunds, land rehabilitation, and improved drainage. Soil texture and SOC levels were strongly influenced by LUTs, showing better results in conserved areas. Soil pH, cation-exchange capacity (CEC), exchangeable Ca2+, and PBS varied with TPs, with higher values found at lower elevations. Higher elevations had somewhat higher SOC, TN, and exchangeable Na+, potentially due to specific replantation efforts, though these increases were not statistically significant. However, WMPs were less effective on lower-elevation farmlands, with minimal impact on combating land degradation. This underscores the necessity for comprehensive and tailored sustainable land management approaches in these areas to enhance soil quality.

Keywords

• Watershed management
• soil properties
• land use
• topography
• Conserved and non-conserved micro-watersheds
• Manuel Tejada, Cristalografía, Mineralogía y Química Agrícola, Universidad de Sevilla, Spain