FCCs obtained from LISS III and IV sensors (with 23.9 m and 5.8 m spatial resolution) were evaluated for delineation of
eroded areas. It was observed that the data enabled better delineation of small units of eroded areas. Based on soil, slope, and land use/land cover, current soil erosion status was mapped. Visual interpretation involves identification and
delineation of degraded lands that are manifested on False Color Composite (FCC). The False Color Composites are analyzed initially with the help of topographical maps, published reports and other available ancillary data; broad categories of degraded lands were delineated. Soil erosion categories were delineated through visual interpretation of IRS data and found to be none or slight, moderate, severe and very severe as shown in the Fig. 3. Land degradation has numerous environmental, economic, social and ecological consequences. Every ecosystem on the earth is affected by some or the other form of land degradation. When land is degraded, the ecology is damaged. There can be rather serious effects in terms of soil erosion, loss of soil fertility and thus reduced plant growth or crop productivity,clogging up of rivers and drainage systems, extensive floods and water shortages. Accelerated erosion adversely affects the quality of soil on site and its agronomic productivity. The eroded areas were identified distinctly on the FCC as a result of erosion of soil
by running water. They are more common on sloping surface. Fig. 3 shows the soil erosion map of the site on 1:50,000 scale.The RUSLE calculation considered all the variables which affect the soil erosion. These parameters affecting soil degradation like have been generated from fieldwork data and have been classified according to the RUSLE in integer values to obtain the ranges for the assessment of the risk of Water Erosion (Fig. 4) and assessment of present Water Erosion (Fig. 5) and those two map were generated using Geostatistical approach for predicting the spatial distributions of maps in Figs. 4 and 5. Integrating different types of the factors affecting land erosion,the results show that the majority of the study area fall under the moderate land erosion classes. High land degradation class has been found in areas affected by high soil loss; this is the major reason for Biological Degradation by removing plow layer of the top soil. It is a well-known fact that soil organic matter is the main biological wealth of soils. Erosion removes the SOM (Soil Organic Matter) along with other mineral components of the soil resulting in soil biological degradation. GIS spatial modeling tools manifested great efficiency in land degradation assessment process, whose results hopefully may help decision makers to take the necessary actions to protect the most degraded spots. These outputs have been analyzed and weighted in terms of degradation classes. Moderate and high classes depend on the magnitude of annual soil loss (RUSLE). It is almost impossible to avoid topsoil compaction. On the other hand, tillage and natural processes can re-loosen the topsoil.
Subsoil compaction is much more persistent and difficult to remove. Artificial loosening of the subsoil has proven to be
disappointing. The loosened subsoil is recompacted very easily and many physical properties are strongly reduced.
Subsoil compaction should be prevented instead of being repaired or compensated. Even on weak soils, relatively high
wheel loads are possible by using large tyres with low inflation pressures or well-designed tracks. Subsoil compaction during plowing can be prevented by using improved steering systems and adapted plows allowing the tractor to drive with all wheels on the untilled land. It is also possible to concentrate wheel loads on permanent traffic lanes and limit the compaction to these sacrificed wheel ways. By using gantries, the sacrificed area can be limited. However, these solutions are rarely used because of short-term economical constraints, lack of awareness, and negligence because the damage to the subsoil is not readily visible. Also the limited knowledge and data on soil strength under dynamic loading makes prevention of subsoil compaction difficult. Provisional map of Bulk density and Physical degradation risk initial levels of soil in investigated area to compaction, based on soil properties alone. Further input data are required on climate and land use before vulnerability to compaction of subsoil in the investigated area can be inferred from the map shown in Figs. 6 and 7.