High-gypsum Byproducts as Soil Amendments for Horticultural Crops

The beneficial influences of gypsum on soil improvement and plant growth have been well-documented, Among these benefits are reclamation of sodic soils, alleviation of subsoil acidity problems, and contribution of Ca and S as nutrients. There are three industrial byproducts that contain significant amounts of gypsum. Phosphogypsum is probably the best-known byproduct gypsum source; the others are clean-air technology coal combustion byproducts, namely fluidized bed combustion and flue gas desulfurization residues. This review summarizes the beneficial chemical and physical effects of gypsum on soil properties and the resultant benefits on plant growth. Where applicable, emphasis is placed on potential uses and limitations of byproduct gypsum sources on horticultural crops. The potential for incorporating these materials in artificial mixtures with organic materials is discussed.