Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/25/2000
Publication Date: 12/1/2000
Citation: CODLING, E.E., CHANEY, R.L., MULCHI, C.L., WRIGHT, R.J. USE OF DRINKING WATER TREATMENT RESIDUE AND IRON RICH RESIDUE TO IMMOBILIZE PHOSPHORUS IN POULTRY LITTER AND HIGH PHOSPHORUS LITTER-AMENDED SOILS.. JOURNAL OF ENVIRONMENTAL QUALITY. 2000.
Interpretive Summary: Poultry litter is used as a fertilizer for cropland. Because it has been applied at N fertilizer rates for decades, soil phosphate (P) has amassed to high levels. Erosion or runoff of this soil P can cause eutrophication of surface waters. Due to the long history of litter application, these soils are very high in plant available P. State regulations would prevent further applications until available P drops to regulated levels. Coastal Plain soils have low levels of Fe and Al oxides which adsorb P in soils and prevent leaching, so these soils comprise a greater P leaching risk than most other soils. Farmers with these soils will be at an economic disadvantage and alternatives are needed to help them comply. Application of Al or Fe rich byproducts to adsorb or precipitate soil P is one method to lower plant available and water soluble P in soils to meet the limits. We characterized several Fe and Al rich byproducts [drinking water treatment residue (DWTR); iron rich residue(IRR)] which may be useful to immobilize soil P, and measured the effect of adding several rates of these byproducts on the solubility of P in litter and soil using soil incubation with varied rates of the DWTR and IRR for 0-7 weeks. DWTR reduced P solubility more than did the IRR. At higher application rates, DWTR reduced water soluble P below 1 mg/L, and plant available P below 200 mg/kg soil from over 1000 mg/kg. Thus, application of DWTR could quickly and effectively reduce risk from soil P, and help farmers with fields high in P meet the new soil P limits. Other properties of DWTR and IRR are non-hazardous for this use, and low costs would allow farmers to use these amendments.
Technical Abstract: Poultry production is concentrated on Maryland Eastern Shore with sandy soils low in sesquioxides. Water quality has been affected by runoff and leaching of nutrients especially phosphorus from poultry litter amended fields. Phosphorus movement is of major concern because P is a limiting nutrient for eutrophication in surface water. The objectives of this study were to: (1) evaluate the ability of drinking water treatment residue (DWTR) and iron rich residue (IRR) to reduce water and Bray-1 P in poultry litter and in three long-term litter-amended soils; (2), determine the effects of these byproducts on pH and electrical conductivity (E C) in the amended litter and soils. Poultry litter was treated with DWTR and IRR at 25, 50 and 100 g kg-1, and three soils, varying in texture, were amended with 10, 25 and 50 g kg-1, and incubated for 7 weeks at 25o C. The treated litter and soils were sampled at 2, 4 and 7 weeks. The two byproduct materials increased the pH of the litter and the soils. The DWTR at the highest rate reduced water soluble P below 1 mg L-1, while reduction in Bray-1 P in litter and soils were > 85% for DWTR and < 58% for IRR compared to controls. The results indicated that water soluble and Bray-1 P in poultry litter and long-term litter amended soils can substantially reduced by incorporating these byproducts high in Al and Fe. Studies are needed to determine the effects of these byproducts on crop yields and composition when applied to soils at rates sufficient to reduce P runoff and leaching.