Submitted to: Technical Report
Publication Type: Research Technical Update
Publication Acceptance Date: 10/5/2014
Publication Date: 10/5/2014
Citation: Mitchell, C.C., Watts, D.B., Torbert III, H.A. 2014. Flue gas desulfurization gypsum agricultural network alabama (cotton). Electric Power Research Institute Grant Final Report. Available: http://www.epri.com/abstracts/Pages/ProductAbstract.aspx?ProductId=000000003002003265.
Interpretive Summary: Power company gypsum is believed to be an excellent source of gypsum that could beneficially improve agricultural production. Thus, research was conducted to compare power company gypsum to mined sources on the performance of cotton production. Addition of gypsum had no effect on cotton lint yield and minimally impacted soil nutrients. No detrimental effects of toxic metals were observed in the soil or water leached through the soil profile from either gypsum source.
Technical Abstract: Flue gas desulfurization gypsum (FGDG) is an excellent source of gypsum (CaSO4•2H2O) that can be beneficially used in agriculture. Research was conducted as part of the Flue Gas Desulfurization Gypsum Agricultural Network program sponsored by the Electric Power Research Institute in collaboration with individual utilities, the USDA-ARS, U.S. EPA, and universities. This report describes work that compared performance of FGD gypsum to that of commercial (mined) gypsum when growing cotton, Alabama’s largest row crop in terms of acreage and value. Most cotton producers rotate cotton with peanuts, a crop that is commonly fertilized with gypsum. Thus, producers are familiar with agricultural gypsum application. A field experiment, established in 2009 on a Bama very fine sandy loam soil near Huxford, AL, was set up as a randomized complete block design with four blocks (replications) of nine soil amendment treatments. Flue gas desulfurization gypsum, from the Lowman Power Plant (Leroy, AL), and a commercially-available agricultural (mined) gypsum were each applied at rates of 1.0, 2.0, and 4.0 ton acre-1 (2.24, 4.48, and 8.96 Mg ha-1), and there was one control (i.e. zero rate) treatment in each block. Two other treatments included agricultural lime at 2.24 Mg ha-1 applied alone or combined with the low rate (2.24 Mg ha-1) of FGD gypsum. Soil amendment treatments were applied only at the beginning of the study and not in succeeding years. Sampling and analysis parameters included gypsum chemistry, soil chemistry at 0-20 cm depth, vadose zone water chemistry at 60 cm depth, cotton lint yield, and cottonseed chemistry. There were no significant effects of gypsum treatments on cotton lint yield in 2009 (598 to 699 kg ha-1) or 2010 (638 to 799 kg ha-1). When measured after 5, 12, and 20 months, soil properties such as pH, lime test index, Bray-1 P, exchangeable cations (K, Ca, Mg, Na), base saturation of exchangeable cations, and loss on ignition (organic matter) were not affected by treatments. After 5 months, soil soluble salts (soil EC) and Mehlich-extractable S were greater for the high rates of FGD gypsum and mined gypsum versus the control treatment. There were no significant gypsum treatment effects on concentrations of As, Hg, or Se in soil, cottonseed, or vadose zone water. In summary, when FGD gypsum was applied at rates of 8.96 kg ha-1 (4.0 ton acre-1) or less on land where cotton was being grown in Alabama, there seemed to be little effect on cotton lint yields or on soil, plant and water quality.