Use of Amendments in Ameliorating Soil and Water Sodicity

Abstract

Sodic soil needs chemical reclamation and also organic amendments for making it useful to produce crops. Reclamation of sodic soil requires removal of part or most of the exchangeable sodium, improvement of the soil physical structure and lowering of pH value. Apart from gypsum, there are certain inorganic amendments that can be used to reclaim sodic soils. Among organic amendments, pressmud, a waste product from sugar factories, is one such material commonly used for soil improvement. Organic amendments on decomposition result in high partial pressure of CO2 and produce organic acids. These processes help to increase electrolyte concentration, mobilize calcium through enhancing the solubility of soil calcite and lower pH and ESP of the soil. Most commonly used amendments are crop residues, farm yard manure (FYM), green manure, poultry manure, etc. Organic materials, when applied in conjunction with inorganic amendments or when applied alone in soils of mild sodicity, have proved beneficial, and therefore their use in the reclamation of sodic soils occupies an important place. Phytoremediation approach is also found to be effective where cultivation of salt-tolerant plant species helps in dissolving native CaCO3 to provide adequate calcium for effective Na+-Ca2+ exchange at the exchange sites.