Flue gas desulfurization gypsum and grass buffer strips influence on runoff and nutrient loss from inorganically and organically fertilzed corn on a US Coastal Plain soil

Authors: ENDALE, DINKU; Strickland, Timothy - Tim; Schomberg, Harry; Bosch, David - Dave; Pisani, Oliva; Coffin, Alisa

Submitted to: Journal of Soil and Water Conservation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/20/2021
Publication Date: 7/26/2021
Citation: Endale, D.M., Strickland, T.C., Schomberg, H.H., Bosch, D.D., Pisani, O., Coffin, A.W. 2021. Flue gas desulfurization gypsum and grass buffer strips influence on runoff and nutrient loss from inorganically and organically fertilzed corn on a US Coastal Plain soil. Journal of Soil and Water Conservation. https://doi.org/10.2489/jswc.2021.02156.
DOI: https://doi.org/10.2489/jswc.2021.02156

Interpretive Summary: Keeping viable agricultural productivity in an environmentally acceptable manner in the southeastern United States will require overcoming current soil, weather, and management challenges. Broiler litter (litter) and gypsum produced as a by-product from coal fired power plants (flue gas desulfurization gypsum), both readily available in the Southeast, have the potential to rectify some of these constraints. However, the tradeoffs between benefits and risks associated with their use must be evaluated. ARS scientists from Tifton, GA and Beltsville, MD evaluated how combinations of fertilizer, gypsum, and grass buffers would impact nutrient loss (ammonium-N, nitrate-N, total N, and soluble reactive and total P) through runoff from corn plots treated with 6 tons per acre per year of litter and gypsum. Rainfall runoff decreased by 54% to 70% under no buffer but with litter or (litter + gypsum) compared with inorganic fertilization, or with addition of buffers or (buffers + gypsum) compared with no buffers under inorganic or litter fertilization. Gypsum treatment on buffer and corn plots reduced nutrient losses 55% to 70% compared with the (no buffer + inorganic fertilizer) control, and also compared with the (no buffer + litter control). Results point to a great potential for reducing edge of field nutrient losses by using readily available flue gas desulfurization gypsum as a soil amendment, especially where litter is used as fertilizer source.

Technical Abstract: Broiler litter (BL) and flue gas desulfurization (FGD) gypsum (gypsum hereafter unless shown otherwise), both readily available in the Southeast, have the potential to rectify soil, weather, and management related constraints that adversely affect agricultural productivity and environmental quality in the region. However, the tradeoffs between benefits and risks associated with their use must be evaluated to optimize their use. In this field study conducted near Tifton, GA, from April 2014 through January 2017, we tested the hypothesis that gypsum applied on cultivated areas fertilized with inorganic (NPK) or organic (BL) sources, and on 6.1 (20ft) long downslope grass buffers, would reduce edge of field losses of nutrients from Coastal Plain soils. Rates for BL and FGD gypsum were 13.45 Mg ha-1 each. We evaluated the buffer effect [(no buffer, buffer alone, and (buffer + gypsum)] under each of three fertilizer regimes [(NPK, BL, and (BL + gypsum)], and fertilizer effect under each buffer type, on runoff and concentration and load of nitrate-nitrogen (NO3-N), ammonium-nitrogen (NH4-N), total Kjeldahl nitrogen (TKN), dissolved reactive phosphorus (DRP), and total P (TP) from 29 storms from May, 2015 through January, 2017. The rainfall amount partitioned into runoff (percent runoff hereafter) decreased by 54% to 70% under no buffer but with BL or (BL + gypsum) compared with NPK, or with addition of buffers or (buffers + gypsum) compared with no buffers under NPK or BL. The [(buffer + gypsum) + (BL + gypsum)] treatment reduced nutrient load by 55% to 70% compared with (no buffer + NPK), a quasi-control, and reduced nutrient concentration 70% to 80% and load 55% to 70% compared with (no buffer + BL), another quasi-control. There was 35% to 80% reduction in concentration or load for different nutrients as a result of interactions between fertilizer and buffer treatments. On the other hand, with no buffers, BL increased concentration but not load of TKN by 82% and DRP and TP by ~160% each, and (BL + gypsum) increased concentration of DRP by 150% and TP by 115%, and NO3-N load by 40% compared with NPK. The results point to a great potential for improving edge of field runoff quality in southeastern cropping systems, especially where BL is used as fertilizer source, by using readily available FGD gypsum as a soil amendment. Similar studies conducted at field and watershed scale would be needed to evaluate how well the findings from this study scale up to these levels.