This article provides a notes on the Gypsum Requirement (GR) of soil. The main principle for the reclamation of sodic or alkali soils is to replace exchangeable Na by another cation calcium (Ca2+). Of all calcium compounds, gypsum (CaSO4.2H2O) is considered the best and cheapest for the reclamation purpose. Calcium (Ca2+) solubilized from gypsum replaces […]