Benefits and constraints for use of FGD products on agricultural land

Considerable amounts of coal combustion products (CCPs) are generated when coal is burned for generation of electricity. To meet Clean Air standards, large amounts of S must not be emitted into the atmosphere, which means con siderable amounts of Rue gas desulfurization products (FGDs) are and will b e produced. Beneficial uses of FGDs are continually being sought to reduce waste, decrease cost of disposal, and provide value-added products. Benefic ial agricultural uses of FGDs include application as amendment to acidic so il to mitigate low pH problems (Al and Mn toxicities): provide plant nutrie nts (i.e. Ca, S, and Mg): improve soil physical properties (e.g. water infi ltration and soil aggregation); help alleviate soil compaction and improve aggregate stability of sodic soils: and inactivate P under high P-soil cond itions to reduce P runoff. Go-utilization of FGDs with organic materials (m anures, composts, biosolids) should also provide many benefits when used on land. Constraints for use of FGDs on agricultural land could be both insuf ficient or excessive amounts of CaCO3, CaO, and/or Ca(OH2) in raising soil pH insufficiently or too much; excessive Ca to cause imbalanced Mg, P, and K in soils/plants; Ca displacement of Al from soil exchange sites to induce Al toxicity in plants; high B to induce B toxicity in plants; excessive su lfite which is toxic to plants; and excessive amounts of undesirable trace elements (e.g. As, Cd, Cr, Ni, Pb. and Se) which could potentially contamin ate water and pose toxicity to plants/ animals/microorganisms. Most constra ints should not impose problems for FGD use on land. Published by Elsevier Science Ltd,