SOIL EROSION ASSESSMENT BY APPLICATION OF RUSLE MODEL IN NTCHISI DISTRICT.

Increased Soil loss is a major threat to the agricultural development in Malawi and by extension is also a major hindrance to the overall economic development of the country since the Malawian economy is dependent on agriculture. The problem of increased soil loss is a major trending issue in Malawi just as the case in Ntchisi District. The study aimed at assessing the soil erosion in Ntchisi District, specifically the impact of human activities that accelerate the rate of soil erosion, mapping areas that are vulnerable to soil erosion and assessing the increment rate of soil erosion.
The study used Revised Universal Soil Loss Equation model (RUSLE) to estimate the increase of the rate of erosion and mapping of vulnerable areas. RUSLE parameters were calculated using different datasets from secondary sources which are rainfall erosivity, soil erodibility, slope steepness and slope length, cover and management and the support practice. The rainfall erosivity was derived from a ten years precipitation data and was found as 297.401MJ.mm.ha-1.h-1.yr-. The soil erodibility was calculated using GSD soil data and was found with a value of 0.1218Mg h/MJ/mm. The slope steepness and length were derived using the Digital Elevation model acquired from USGS and was found as 8.516. The cover and management using Landsat images for 2010 and 2020 to denote the influence of deforestation and overgrazing on soil erosion and was found as 0.031 and 0.041 respectively. The support practice was calculated from slope map and based on farming practices in the area and was found with the average of 0.67.
The RUSLE parameters were integrated where by used different cover and management factor as for 2010 and 2020. Using the 2010 cover and management factor the rate of soil erosion was 6.2004 Mg/ha/yr and while using the 2020 cover and management factor, the rate of soil erosion was 8.474 Mg/ha/yr. From 2010 to 2020 there has been an increment of 2.236 Mg/ha/yr. which represents 36.67% Of soil loss due to vegetative cover loss as the result of deforestation and overgrazing that are constantly happening in Ntchisi district.