Assessment of soil loss tolerance

Soil degradation in all its forms has a serious effect on crop and biomass productivity and poses potential threat to sustainability of agriculture. Some soil loss is tolerable but not so much that plant productivity diminishes. Thus productivity is of utmost concern in evaluating soil loss tolerance. The effect of soil loss on productivity is difficult to determine. Therefore other alternative approaches are discussed for computing limits of soil loss tolerance. These approaches are soil profile thickness, rate of soil formation, productivity index and weighted additive model. Assessment of soil loss tolerance (T-value) serves as a tool to gauge the potential erosion risk in the given area with regard to long term sustainability. Thus the T-value must be determined scientifically and rationally. Each approach which is used to determine soil loss tolerance has its own assumptions, advantages and limitations Further the soil loss tolerance is used to calculate the erosion tolerance index (ETI) by considering annual soil loss. These can serve as a guide for policy makers to decide upon effective watershed management plan.