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.

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 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 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. 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.

The study area is Ntchisi district located in the central region of Malawi. The total land area is 655 sq. km. The district has bordered by Dowa and Salima in the south west and south east respectively. Kasungu is in the west and Nkhotakota in the north west. The district lies along the Kasungu- Lilongwe plain which has gentle slope on the western side and undulating hills in the southern position. The northeastern and eastern parts of the district are hilly whereas northern, southern and western are flat and rolling. Ntchisi has slopes ranging 1 to 2 degrees and is at an altitude of between 1300m to 1700 meters above sea level. Ntchisi has sandy loam soils in upland areas and has sand clay soils in dambos down the hills. The mean annual temperature varies between 220c in low altitude areas and 180c in high altitude areas. The district annual rainfall ranges from 900mm to 1500mm. The natural vegetation of the area is typically savanna. Farming and agriculture make up to eighty-five percent of the local economy with couple of leading crops being beans and potatoes. Forestry, irrigation and livestock herding are other fields since the economy has very little private industry and government employs most of the people.

District: Ntchisi

Coordinates: -13.27395, 33.91235