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Efficacy of Alum and Coal Combustion By‐Products in Stabilizing Manure Phosphorus
Author(s) -
Dou Z.,
Zhang G. Y.,
Stout W. L.,
Toth J. D.,
Ferguson J. D.
Publication year - 2003
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2003.1490
Subject(s) - alum , manure , chemistry , phosphorus , dry matter , zoology , broiler , flue gas desulfurization , agronomy , food science , organic chemistry , biology
Animal manures contain large amounts of soluble phosphorus (P), which is prone to runoff losses when manure is surface‐applied. Here we report the efficacy of alum and three coal combustion by‐products in reducing P solubility when added to dairy, swine, or broiler litter manures in a laboratory incubation study. Compared with unamended controls, alum effectively reduced readily soluble P, determined in water extracts of moist manure samples with 1 h of shaking, for all three manures. The reduction ranged from 80 to 99% at treatment rates of 100 to 250 g alum kg −1 manure dry matter. The fluidized bed combustion fly ash (FBC) reduced readily soluble P by 50 to 60% at a rate of 400 g kg −1 for all three manures. Flue gas desulfurization by‐product (FGD) reduced readily soluble P by nearly 80% when added to swine manure and broiler litter at 150 and 250 g kg −1 Another by‐product, anthracite refuse fly ash (ANT), was ineffective for all three manures. In all cases, reduction in readily soluble P is primarily associated with inorganic phosphorus (P i ) with little change in organic phosphorus (P o ). Sequential extraction results indicate that the by‐product treatments shifted manure P from H 2 O‐P into a less vulnerable fraction, NaHCO 3 −P, while the alum treatment shifted the P into even more stable forms, mostly NaOH‐P. Such shifts in P fractions would have little influence on P availability for crops over the long term but would retard and reduce potential losses of P following manure applications.