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Title: GROWTH OF FORAGE LEGUMES AND GRASSES IN ACIDIC SOIL AMENDED WITH FLUE GAS DESULFURIZATION PRODUCTS

Author
item CLARK, R - USDA-ARS (RETIRED)
item Baligar, Virupax

Submitted to: Communications in Soil Science and Plant Analysis
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/31/2002
Publication Date: N/A
Citation: N/A

Interpretive Summary: When coal is burned to generate electricity, considerable amounts of flue gas desulfurization products (FGDs) are produced. These products have potential to be used as soil amendments, but information about FGD effects on plant growth and mineral nutrition is scarce. Glasshouse experiments were conducted to determine beneficial and/or detrimental effects of various levels of three FGDs plus calcium-carbonate (CaCO3), -sulfate (CaSO4), and -sulfite (CaSO3) (major constituents of FGDs) on growth and mineral acquisition by alfalfa, white clover, orchardgrass, tall fescue, switchgrass, and eastern gamagrass grown in acidic soil. The FGDs enhanced growth of each plant species at specific levels added to soil, with alfalfa, white clover, and tall fescue exhibiting the greatest increases, especially when plants were grown in soil amended with an FGD containing added magnesium. Shoot mineral concentrations of most minerals required for rplant growth remained relatively normal when plants were grown with the various levels of FGDs. Accumulation of trace elements in plant tissue is a concern with FGD use, but these elements were well below critical toxicity concentrations and normal for plant foliage. These FGDs could be used beneficially in soil if applied at appropriate levels.

Technical Abstract: Large amounts of flue gas desulfurization products (FGDs) are produced when SO2 emissions are trapped in the coal burning process for generation of electricity. FGDs are normally discarded instead of being reused, and reuse on soils could be important in overall management of these products. Glasshouse experiments were conducted to determine effects of various levels of three FGDs (a FGD gypsum, an oxidized FGD + Mg, and a stabilized FGD) and the control compounds CaCO3, CaSO3, and CaSO4 on growth of alfalfa (Medicago sativa), white clover (Trifolium repens), orchardgrass (Dactylis glomerata), tall fescue (Festuca arundinacea), switchgrass (Panicum virgatum), and eastern gamagrass (Tripsacum dactyloides) in acidic (pH 4) soil (Typic Hapludult). The FGDs enhanced growth of each plant species, with alfalfa, white clover, and tall fescue receiving greater increases than the other species, especially when grown in soil amended with FGD+Mg. FGD gypsum did not often enhance growth unless high amounts were added. FGDs containing high B and low levels of CaSO3 were detrimental to growth. Overall, FGDs improved growth responses of these forage plants grown in an infertile low pH soil.