摘要
This study was conducted to assess land degradation in Longido District,Arusha,Tanzania using remote sensing techniques.Biophysical degradation indicators i.e.land use/land cover,land productivity level and soil erosion were used.Specifically,Landsat Satellite images of 1995 and 2015,together with soil data and digital elevation model were applied.Land cover maps of the study area over the study years were produced by supervised classification method.Soil erosion was assessed using RUSLE(Revised Universal Soil Loss Equation)model producing soil erosion map of Longido district,the inputs into the RUSLE model were rainfall,erosivity factor,soil erodibility factor,slope steepness and slope length factor,cover management factor and support practice factor.Biophysical land degradation map was produced by applying weighted overlay technique whereby soil erosion was given more weight followed by land use/land cover of 2015 and land productivity level of 2015.The findings show that about 38% of Longido district areas are highly vulnerable to land degradation which is above the international allowable level.It is being concluded that Longido District is at high risk of failure to sustain livelihood of and resilient for its communities,the earth in general,so it is timely for the district authorities to take steps towards mitigating further land degradation.It is being recommended that sustainable conservation and management strategies as well as policies must be affected by district authorities including farmers and pastoralists to improvise land degradation friendly cultivation and grazing methods.
