Effects of poultry litter with flue gas desulfurization gypsum bedding on nutrient release and water quality

Authors: POWELL, A - Auburn University; PRASAD, RISHI - Auburn University; Watts, Dexter; CHAKRABORTY, D - Auburn University; Torbert, Henry - Allen

Submitted to: Alabama Water Resources Conference
Publication Type: Abstract Only
Publication Acceptance Date: 5/27/2022
Publication Date: 9/7/2022
Citation: Powell, A., Prasad, R., Watts, D.B., Chakraborty, D., Torbert Iii, H.A. 2022. Effects of poultry litter with flue gas desulfurization gypsum bedding on nutrient release and water quality [ABSTRACT]. Alabama Water Resources Conference.

Interpretive Summary:

Technical Abstract: Gypsum (CaSO4 • 2 H2O) has recently been explored as a poultry litter bedding to reduce ammonia losses from poultry houses, a compounding environmental issue. Additionally, previous studies have shown that gypsum reduces phosphorus runoff losses when land applied with litter. Flue-Gas Desulfurization Gypsum (FGDG) is a man-made byproduct gypsum from powerplant SOx emission scrubbers. While using FGD gypsum bedding will reduce phosphorus runoff losses from land applied litter, less than 2% of FGDG is utilized in agriculture. The objective of this study was to compare nutrient losses from litter with FGD gypsum bedding to traditional and industry standard bedding materials. Two rainfall simulations events were conducted 5 weeks apart (June/July of 2021) on a Pacolet-Rion complex soil at the Piedmont Agricultural Research Station in Camp Hill, AL. The litter treatments selected for the study received an initial bedding (1st flock) of either gypsum + decaked litter, shavings + decaked litter, or decaked litter alone, and then each bedding treatment received either no gypsum or 1,600 lbs/1000 ft2 of gypsum at flock clean-out for the next 5 flocks. Treatments were chosen to compare traditional and gypsum bedding treatments. Additionally, an industry standard ammonia volatilization reduction treatment was chosen to compare to gypsum (for this treatment, 100 lbs/1000ft2 of Poultry Litter Treatment (PLT®) as applied was applied to decaked litter on all 5 flocks. The seven litter treatments and a control (no litter) were applied just before the first simulated rainfall (70 mm/hr) in a randomized complete block with three replications. Samples were taken at initial runoff and at 10-minute intervals for 40 minutes and a composite water sample was taken at the end of the simulation. The samples were analyzed for total phosphorus (TP), dissolved phosphorus (DP), ammonium-N (NH4-N), nitrate-N (NO3-N), Al, B, Ca, Fe, K, Mg, and Zn using standard protocols. Gypsum litter bedding is effective for reducing phosphorus runoff losses compared to the industry standard bedding. While gypsum litter bedding resulted in more nitrogen runoff losses than the control probably due to less uptake by the grass, it served as an excellent alternative bedding to reduce phosphorus runoff losses to the environment.