WATER-EXTRACTABLE PHOSPHORUS REDUCTION IN POULTRY LITTER WITH CALCIUM- AND IRON-RICH BYPRODUCT AMENDMENTS
2004; Volume: 47; Issue: 6 Linguagem: Inglês
10.13031/2013.17804
ISSN2151-0059
AutoresGary K. Felton, Kevin J. Hughes, Estelle Russek‐Cohen,
Tópico(s)Wastewater Treatment and Nitrogen Removal
ResumoIn the poultry producing regions of Delaware, Maryland, and Virginia, long-term application of poultry litter asthe primary crop nitrogen source has resulted in elevated soil phosphorus (P) levels and is suspected of being a source ofdissolved phosphorus in surface waters. Dissolved P is the most readily available form for algal uptake in receiving waters,and hence may disproportionately contribute to eutrophication. One potential solution to this problem that would allow farmersto continue land applying poultry litter is to amend manure with high P-affinity materials. Two high P-affinity materialsproduced in the titanium dioxide manufacturing process, secondary gypsum (SG) and filter cake (FC), were investigated aspotential poultry litter amendments. Both are rich in iron, and SG also contains a significant quantity of calcium and sulfates,primarily in the form of gypsum. Laboratory experiments were conducted to investigate: (1) the appropriate ratio of litterto amendment, (2) the effect of 1, 2, and 4 week incubations on soluble P, and (3) the effect of amendments on poultry litterpH. Four treatments were investigated: (1) poultry litter only, and poultry litter amended with: (2) SG, (3) FC, and (4) a mixture(MIX) of SG and FC. The pH of the amended poultry litter decreased from an initial pH of 8.3 to a pH of 6.2 to 7.0. Amendment-to-litter ratio had the most profound impact on water-extractable phosphorus (WEP). All treatments significantlyreduced WEP as compared to the control samples. Poultry litter to amendment mixtures at a 1:1 (mass basis) rate reducedWEP by 98%. The reduction dropped to 90% for the 2:1 mix, approximately 74% for the 4:1 mix, and 40% to 60% for the8:1 mix.
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