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Impact of Phytase Feeding on Form and Fate of P, Cu, and Zn From Poultry Manure Before and After Application to SoilsEPA Grant Number: U915133
Title: Impact of Phytase Feeding on Form and Fate of P, Cu, and Zn From Poultry Manure Before and After Application to Soils
Investigators: Lawrence, Christophe L.
Institution: Virginia Polytechnic Institute and State University
EPA Project Officer: Manty, Dale
Project Period: January 1, 1997 through January 1, 2001
Project Amount: $102,000
RFA: STAR Graduate Fellowships (1997) RFA Text | Recipients Lists
Research Category: Fellowship - Geology , Academic Fellowships , Ecological Indicators/Assessment/Restoration
The objectives of this research project are to: (1) determine and compare amounts and chemical forms of phosphorus (P), copper (Cu), and zinc (Zn) present in manures from poultry fed various levels of phytase enzyme and from poultry fed a conventional diet; (2) measure and relate the degree to which P, Cu, and Zn from those manures are bound to soil particles or can be solubilized, thus becoming available for plant uptake or movement from the soil; and (3) compare differences in the degree to which four soils with varying properties bind the P, Cu, and Zn compounds in these manures.
Manure will be obtained from turkeys fed conventional diets and diets containing various levels of phytase enzyme supplements. The Department of Animal Science at Virginia Polytechnic Institute and State University will raise the turkeys and evaluate effects of the dietary treatments on bird development as part of a separate research project. Turkey excreta will be collected, and immediately frozen on 3 consecutive days during the fourth week of feeding, and thawed and homogenized for analysis.
Manure samples representative of all treatments will be analyzed for total P, inorganic and organic P, and plant-available P content. Inorganic P will be fractionated into water-soluble, calcium-bound P, and aluminum/iron-bound P. Organic P will be fractionated into inositol or phytate P, phospholipid P, and nucleic acid P fractions. Samples also will be analyzed for total and plant-available forms of Cu and Zn. Cu and Zn then will be fractionated to determine water-soluble, exchangeable, specifically sorbed, organically chelated, and occluded forms.
Surface samples of four soils typical of southeastern poultry-producing regions will be analyzed for P, Cu, and Zn as described above. Phosphorus, Cu, and Zn sorption and desorption characteristics of the soils also will be determined. Soil samples will be mixed with manure in the laboratory, and will be incubated for selected time periods. These manure-amended soils then will be analyzed for P, Cu, and Zn as described above, and their P, Cu, and Zn sorption and desorption characteristics will be determined.