Soil degradation has been defined as a process that leads to decline in the fertility or future productive capacity of soil as a result of human activity (United Nations Environment Programme, 1993).It occurs whenever the natural balances in the landscape are changed by human activity through misuse or overuse of soil. Degraded soils which result in poor or no production are also called problem soils.
Waste lands are those which for one or the other reason have poor life sustaining property. Out of 100 per cent potentially active lands only 44 per cent are available for cultivation and 56 per cent of land are non-available for cultivation.
The wasteland can be made useful by increasing productivity of land by using some useful methods as afforestation or by using bio-fertilizers. Soil degradation is a complex phenomenon derived by interaction between natural and socio economic factors.
The degradation or deterioration of soil may be caused by the following factors:
1. Physical factors, e.g. loss of fertile top soil due to water or wind erosion.
2. Chemical factors e.g. depletion of nutrients or the toxicity due to acidity or alkalinity (salinization) or water logging.
3. Biological factors which affect the micro-flora and reduce the microbial activity of the soil. These factors reduce the yield.