Effectiveness of flue gas desulfurization gypsum in reducing phosphorus solubility in poultry litter when applied as an in-house amendment

Debolina Chakraborty; Rishi Prasad; Dexter B Watts; H Allen Torbert

doi:10.1016/j.wasman.2023.08.014

Effectiveness of flue gas desulfurization gypsum in reducing phosphorus solubility in poultry litter when applied as an in-house amendment

Waste Manag. 2023 Aug 22:171:1-9. doi: 10.1016/j.wasman.2023.08.014. Online ahead of print.

Authors

Debolina Chakraborty¹, Rishi Prasad², Dexter B Watts³, H Allen Torbert³

Affiliations

¹ 201 Funchess Hall, Department of Crop, Soil, and Environmental Sciences, Auburn University, Auburn, AL 36849, USA.
² 201 Funchess Hall, Department of Crop, Soil, and Environmental Sciences, Auburn University, Auburn, AL 36849, USA; Department of Animal Science, Auburn University; Auburn, AL 36849, USA. Electronic address: rzp0050@auburn.edu.
³ USDA-ARS National Soil Dynamics Lab., 411 S. Donahue Dr., Auburn, AL 36832, USA.

PMID: 37619431
DOI: 10.1016/j.wasman.2023.08.014

Abstract

Phosphorus (P) runoff from agricultural lands receiving poultry litter (PL) poses a major environmental challenge. Application of flue-gas-desulfurization (FGD)-gypsum produced from coal power plants in agricultural lands has shown promise to reduce P losses. However, no information is available about the effectiveness of FGD-gypsum addition in reducing P solubility when applied as an in-house amendment. Hence, the objectives of this study were to understand a) effectiveness of FGD-gypsum as a litter amendment in reducing P loss risk; and b) how FGD-gypsum amendment in PL alters the distribution of P forms. Broiler chickens were raised for five flocks in seven individual litter treatments replicated four times in a randomized complete block design. Based on the FGD-gypsum addition, the PL treatments were broadly classified as FGD-gypsum treated and untreated. Toxic metal concentrations were analyzed in FGD-gypsum as well as the treatments. Sequential water extractions were performed to understand P solubility. Litter P fractionation was performed to identify bioavailable P (Water-P), labile P (NaHCO3-P), aluminum/iron chemisorbed P (NaOH-P), and mineral occluded P (HCl-P). Results indicated significantly higher soluble P in all untreated than in all FGD-gypsum treated litters in the initial water extraction. The FGD-gypsum treated litters reduced soluble P by 58 to 67% in the 1st water extraction compared to untreated litters. Fractionation study revealed lower proportion of Water-P and higher proportion of NaHCO3-P and HCl-P in all FGD-gypsum treated than in untreated litters. This study suggests reuse of FGD-gypsum in broiler houses can help reduce P mobility without any toxic metals concerns.