Effects of flue gas desulfurization gypsum-amended poultry litter on nutrient release and water quality

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

Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 7/11/2022
Publication Date: 11/7/2022
Citation: Powell, A., Prasad, R., Watts, D.B., Chakraborty, D., Torbert Iii, H.A. 2022. Effects of flue gas desulfurization gypsum-amended poultry litter on nutrient release and water quality [ABSTRACT]. ASA, CSSA, SSSA International Annual Meeting, November 6-9, Baltimore, Maryland.

Interpretive Summary:

Technical Abstract: Poultry litter (PL) has been historically applied to hayfields, but overapplication of PL can result in nutrient loss to aquatic ecosystems and eutrophication. In previous studies, gypsum has reduced phosphorus runoff losses and ammonia losses when used as a bedding material for broilers. The objectives of this study are to compare nutrient losses from PL with gypsum-amended bedding to conventional bedding materials. The PL which received gypsum bedding will reduce nutrient losses from the land applied litter compared to PL with conventional bedding materials. The litter treatments received initial bedding (flock 1) of gypsum+decaked litter, shavings+decaked litter, or decaked litter only and gypsum amendments (1600lbs/1000ft2) or no gypsum for flocks 2-5. Additionally, a litter treatment that received Poultry Litter Treatment® (PLT®) (100lbs/1000ft2) was included as an ammonia reduction industry-standard treatment. A rainfall simulation study was conducted to determine nutrient runoff for 7 litter treatments. The litter was applied at 200lbs N/acre in random complete block design with three replications before the first simulation was conducted. A second rainfall simulation was conducted 5 weeks later (70 mm/h rainfall rate). Water samples were collected at initial runoff and every 10 minutes for 40 minutes. The water samples were analyzed for total phosphorus (TP), dissolved phosphorus (DP), ammonium-N, nitrate-N, and seven other nutrients, using standard protocols. All litter treatments that received gypsum bedding were found to significantly reduce TP and DRP loads (56-90%) in the “first flush” event (simulation 1) compared to the PL with industry standard bedding, PLT®. Ammonium-N loads for the litter with PLT® were only significantly greater for the PL that received gypsum bedding for flocks 1-5. No differences were observed in litter treatments for nitrate-N loads. Gypsum is an excellent alternative litter bedding and is effective for reducing phosphorus runoff losses compared to the industry standard for ammonia losses.