Tuesday, November 14, 2006
217-10

Phosphorus Dynamics in Soils Amended with Raw, Ground, Heated, and Granulated Poultry Litters.

Gurpal Toor, Agriculture Dept, Univ of Arkansas, Fayetteville, AR 72701 and Brian Haggard, USDA-ARS, Univ of Arkansas, Ag Eng Dept, 203 Engineering Hall, Fayetteville, AR 72701.

Phosphorus (P) losses from intensive poultry production regions can increase eutrophication of natural waters. To environmentally and economically sustain poultry operations, effective approaches to manage poultry litters are vital. These may involve reducing P in litters by dietary modification or transporting excess poultry litter to other areas where it can be more efficiently used. Soil test P has reached to values of environmental concern in areas where manures are frequently applied. In these areas, alternatives to land application of litter need to be exploited, which are not always feasible because of the economic factors such as cost of litter transport. As poultry litter is a mixture of excreta and bedding material with variable dry matter content, there are concerns with regard to transport of fresh litter. Therefore, some form of post-processing of poultry litter would aid to transport litter without these concerns. Granulation of poultry litter is one such option which involves heating and drying during which water is used as a binding material to make granules. Other materials such as Urea can be added during granulation process to increase nitrogen (N) content of final product, thus bringing N to P ratio of litter closer to most crops requirement. The objective of this study was to evaluate the effect of granulated poultry litter products that contained Urea alone, Urea plus Dicyanamide, and Hydrolyzed Feathermeal on water extractable P (WEP) and Mehlich 3 P (M3-P) in soils. We incubated two soils for 21 d with poultry litters applied at two rates: (i) P based application (100 kg total P/ha) and (ii) N based application (160 kg plant available N/ha). Sub-samples were removed at 1d, 7d, and 21 d after incubation for analyses. Results and implications of N and P based application strategies on soil WEP and M3-P will be presented.