Examination of Land Degradation based on Erosion Potential using Revised Universal Soil Loss Equation (A Study Case of Bandung Regency, West Java, Indonesia)
Abstract
Soil erosion is a serious environmental problem in the world. With the generally high erosion rate in many parts of the world, efforts should be directed towards curtailing its hazard. This requires quantitative data to identify critical areas where urgent conservation is needed. Traditional approaches based on runoff plots are expensive, time consuming and generate point-based data. A comparative study was conducted to estimate soil loss under landscapes, major land uses and slope gradients in Bandung Regency, West Java Province, Indonesia. The soil erosion model, i.e. the Revised Universal Soil Loss Equation (RUSLE) was applied in GIS and remote sensing (RS) environment. GIS based spatial analysis model is used to answer questions about what exists now or exists at some points in the past. Perhaps most importantly, it can be used to predict what will happen or has happened in another location or at another point in a certain time. A GIS provides these capabilities by means of its spatial analysis function. Erosion that is caused by rain and human’s activities can be assessed with the Revised Universal Soil Loss Equation in ton/hectare/year units based on soil loss rate of a certain area. RUSLE involves erosivity from rain, erodibility from soil properties, slope conditions, land conservation, and cultivation system factors on a land. The classification of land cover in study area was conductive by using Landsat satellite image of different years, i.e.1989, 1993, 1998 and 2003. Changes in land use/ cover was led to increase the rate of erosion by water in the Bandung regency which could be concluded from the statistical analysis of the annual result from RUSLE. The potential eroded area by districts in the study area can be examined. Human factor, land use and cover change, is the most dominant factor in RUSLE equation for prediction of land degradation was shown in the sensitivity analysis of land use/cover change by years. According to the outcome of this research, deforestation and the agricultural practice for vegetable farming in the study area were causing problems of land degradation. Intensification of agriculture area and residential area are major factors of land degradation in the study area. Finally, this research can be concluded that 1825 hectare of land in the Bandung regency is continuously suffered high and very high erosion in four different period of land cover type. That area need to be recognized as “rehabilitant area” and must be maintained with the way of high soil conservation practice. The forested area which located more than 40 percent slope gradient in the study area is needed to be identified as highly value conservative forest area. Erosion must be noticed in a land degradation management and RUSLE can help farmers not only to assess erosions on their lands but also to policy maker for implementing the land use planning.
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- MT - Professional Master [880]