Soil degradation is one or the other form and consequent decline in soil productivity which has been the experience of the farmer since ancient times. As population pressure on agricultural land increases, concerns for ensuring sustained agricultural productivity of soils are being voiced more vociferously now. Chemical degradation of soils takes place as these accumulate soluble salts or toxic elements in amounts deleterious for plant growth or their chemical properties are so transformed as to adversely affect their productivity. The losses in soil productivity may also be accompanied by ecological obliteration and environmental degradation of the whole area. Continuous use of inorganic fertilizers coupled with depletion of organic matter results in deterioration of soil structure and soil productivity. It leads to reduce input/output ratio unless soils are replenished with organic matter through green manure, farm yard manure (FYM), compost or through microbial activity. Due to repeated application of microbes like blue green algae (BGA), bio-fertilizer soil organic carbon content is not only maintained but enriched too. The increase in carbon content of saline soil of Andhra Pradesh (India) has been shown to be up to 22%. The microbial polysaccharides are regarded as the most important natural products in the formation and stabilization of soil aggregates.
Part of the book: Biostimulants in Plant Science