Three annual flue gas desulfurization gypsum applications on macronutrient and micronutrient losses in runoff from bermudagrass fertilized with poultry litter

Authors: Watts, Dexter; Torbert, Henry - Allen

Submitted to: Soil Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/4/2016
Publication Date: 2/10/2017
Publication URL: http://handle.nal.usda.gov/10113/5661739
Citation: Watts, D.B., Torbert III, H.A. 2017. Three annual flue gas desulfurization gypsum applications on macronutrient and micronutrient losses in runoff from bermudagrass fertilized with poultry litter. Soil Science. 182:18-27.

Interpretive Summary: Flue gas desulfurization gypsum (FGD) is a by-product of producing electricity at coal-fired utility plants. Interest in using FGD gypsum as a soil amendment for suppling calcium (Ca) and sulfur (S) nutrition for crops, improving soil structure, and reducing phosphorus (P) loss from agricultural fields has increased in recent years. Gypsum use with manure application is also being encouraged as best management practice for reducing the loss of soluble P with surface water runoff. However, there is some indication that the gypsum may increase the loss of the beneficial nutrients added to soil from manure sources. Thus, a rainfall simulation study was conducted using high rainfall rates to evaluate how adding FGD gypsum to soil and with poultry litter (PL) would influence the loss of nutrients in surface water runoff. Two runoff events were created; one 30 min after FGD gypsum and PL application and the other 6 months later. When FGD gypsum was applied to the field by itself, generally only Ca and S losses increased with surface water runoff. Poultry litter addition alone increased N and P in both runoff events and Potassium (K) in the initial event only. Adding gypsum with PL decreased N and P losses, while increasing K, Magnesium (Mg) and Manganese (Mn), primarily during the initial runoff.

Technical Abstract: Considerable amounts of flue gas desulfurization (FGD) gypsum are being produced as a by-product of generating electricity. As a result, beneficial reuse of this by-product is being sought to reduce landfilling and its associated cost. The use of this byproduct as a low-cost soil amendment for suppling Ca and S to crops, improving soil structure, or reducing P loss from agricultural fields may be a viable alternative for easing the burden of disposal. In order to better understand the influence FGD gypsum has on nutrient losses with surface water runoff, rainfall simulations were conducted on an Ultisol (Luverne sandy loam; fine, mixed, semiactive, thermic Typic Hapludults) in a bermudagrass (Cynodon dactylon L.) hayfield typical of the Coastal Plains region. Treatments consisted of applying 0, 2.2, 4.4, and 8.9 Mg ha-1 FGD gypsum with 13.4 Mg ha-1 PL plus a non-fertilized check (no PL or FGD gypsum) and 8.9 Mg ha-1 FGD gypsum only as controls. All treatments were applied each May from 2009 to 2011. In 2011, two simulated rainfall events (~85 mm h-1) were created to promote runoff for 60 min, one immediately after treatment application and the other 6 months later (end of growing season). The greatest nutrient losses observed were generally during the initial runoff event immediately following PL application. The addition of FGD gypsum only generally increased Ca and S losses regardless of when the simulated runoff event occurred. Poultry litter additions increased inorganic N (NO3-N and NH4-N), total N, and total P losses in both runoff events, and K in the initial runoff event only. Adding FGD gypsum with PL decreased total N and P concentration losses while increasing K, Mg, and Mn, primarily in the initial runoff event. Concentrations of Al and Fe in runoff were generally minimal or below detection limits.