IMPACT OF SOIL CONDITION, TOPOGRAPHY AND LAND USE ON THE EROSION CHARACTERISTICS OF PHULENG-E-NYANE, HA MANTSEBO: A USLE ANALYSIS THE NATIONAL UNIVERSITY OF LESOTHO
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Date
2025-10-01
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Abstract
Soil erosion is a natural yet complex process resulting in the detachment and movement of soil by agents including water and wind, often accelerated by anthropogenic activities such as agriculture and land use changes. It threatens soil fertility, agricultural productivity and ecosystem health making its assessment crucial for sustainable land management. In this study, the impact of soil erosion causing factors on the erosion characteristics of Phuleng-e-Nyane Ha-Mantšebo were evaluated using the Universal Soil Loss Equation (USLE) model. A randomized complete block design in a split plot arrangement was employed to assess soil erosion across the area. The main plot consisted of two farming systems, cropland and long-term fallow land. Within each farming system, the subplot factor was the topo-sequence position comprising four levels: summit, shoulder, back-slope and toe-slope. The soil erosion factors used to determine the total soil loss in USLE include, rainfall erosivity index, soil erodibility factor, topographic factor, crop management factor and conservation factor.
Disturbed and undisturbed soil samples were collected, whereby, the disturbed soil samples were collected using soil auger at 30 cm depth and undisturbed soil samples using the core samples. The secondary rainfall data for Moshoeshoe I International Airport was collected from the Lesotho Meteorological services while the slope length was measured using the 100 m fiberglass open reel measuring tape. Google earth was used to look at land use and land cover overtime. Correlation analysis was used to examine the relationship between soil loss and the contributing factors. The localized soil loss prediction model was developed. The total soil loss from study area was calculated at 12.25 Mg ha⁻¹ yr⁻¹ with cropped land contributing about 95.2% of the loss (about 53.7% from the north transect and 41.5% from the southwest transect) while 4.8% was from the long-term fallow land approximately shared equally among the two transects. The stepwise regression analysis revealed that land use is the most influencing factor on soil loss from the area, followed by topography. The study highlights the importance of integrating effective management practices to sustain soil health and reduce erosion hazards.