LAND PLANNING FOR SUSTAINABLE DEVELOPMENT IN WATERSHEDS USING GEOGRAPHICAL INFORMATION SYSTEM

摘要

The lack of adequate land use planning and soil knowledge have been one of the major problems to develop soil conservation politics to avoid environmental degradation in Brazil. The application of soil erosion models, like the Univesal Soil Loss Equation (USLE) through GIS to predict soil loss and to assess crops and soil management has been effectively used to elaborate soil erosion inventories by integration of physiography, soils, landuse/landcover, slope map layers and land evaluation. This paper describes the application of the above technologies in a watershed area at Sao Paulo-state southwestern region, Brazil. The main soil types of the area (Ultisol an Alfisol) are very susceptible to erosion due to the great difference in clay content between A and B horizons. Sugarcane and pasture are the main land use comprising almost 90percent of the area. The soil loss rates varied from 0.1 t.ha~(-1).yr~(-1) in forest areas to 30 t.ha~(-1).yr~(-1) in sugarcane areas. The erosion risk map obtained through USLE showed that 54percent of the area was classified as medium to high erosion risk. Approximately 30percent of sugarcane production occur in theses areas which indicates that a suitable land use for these areas should consider careful management practices.