The main chemicals reported for soil amelioration include
gypsum, phosphogypsum, flue gas desulfurization gypsum, calcium
chloride, sulfuric acid, sulfur, iron pyrite, and aluminum sulfate
Among
these substances, gypsum-like solid Ca2+ amendments are the
most common chemicals applied to large areas. Gypsum and
desulfurized gypsum application followed by freshwater leaching
ameliorates hard saline–sodic soils and enhances the grain yield of
rice
However, the dissolution
rates of gypsum-like amendments are generally low, and their
coagulation abilities for soil colloid particles require improvement.
Several years may be necessary to effectively ameliorate hard
saline–sodic soils
Inorganic polymeric coagulating chemicals applied in water
treatment can achieve rapid flocculation and sedimentation of
colloidal particles in water bodies