Modeling the Impact of Land Cover Changes on Soil Erosion Estimation in Yewa North and Yewa South, Ogun State, Nigeria

Abstract

Soil erosion is becoming a serious problem in some communities in Yewa North and Yewa South because of rapid land use developments. This study was carried out to analyses the landcover change effects on soil erosion to determine the extent and trend of changes in the study area; estimate and characterize soil loss, and comparing the annual soil loss at different spatial scales. The extent and trend of changes in the landcover were estimated using Landsat Satellite Imageries for the year 2002 and 2017. RUSLE model was used to estimate soil loss and was characterized based on the expert description for tolerable soil loss concept. The results revealed the built-up area showed a consistent increase over time, from 349.5km2 in 2002 to 592km2 in 2017 of the total area. The vegetation covered about 933.4km2 in 2002 but decreased to 509km2 in 2017. Similarly, the area covered by bare ground increased from 243.7km2 in 2002 to 620.4 km2 in 2017 but the waterbody increased from 0.29km2 in 2002 to 0.72km2 in 2017. The areas covered by agriculture also decreased from 1088.5km2 in 2002 to 894km2 in 2017. The estimated soil loss values ranged from 0 – 420,276 t ha-1 yr-1 with the mean of 231 and standard deviation 2272 in 2002 while the soil loss estimated in 2017 ranged from 0 – 186,920 t ha/ yr. with the mean of 220 and the standard deviation 1312.3. Comparatively, low erosion is observed in a total area of 45.5% in 2002 and 44.4% in 2017 while extremely severe erosion is observed in a total area of 29.8% in 2002 and 34.3% in 2017 in the study area which matches the actual bareground and agricultural land which can be attributed to change in C and P factors. The study recommended that enlightenment and awareness of erosion control should include land use habit of the people in the agricultural practice and care of vegetation