Effects of Pelletized and Non-Pelletized Poultry Litter and Nutrient Immobilizing Agent On Surface Runoff Water Quality From a Forage Based System.

Poultry litter has been recognized as an organic fertilizer that improves soil fertility by adding essential plant nutrients and organic matter.  Poultry litter is being pelletized to increase the economic feasibility of transporting litter from production sites to the areas is needed.  Compared to non-pelletized litter, little is known about its impact on surface runoff water quality.  Since the potential impairment of surface water from poultry litter has always been of concern, particularly if litter is not incorporated into the soil, it is critical to investigate whether the effect of  pelletized litter relative to non-pelletized litter is different on the potential export of bacteria, water-soluble nutrients (NH4, NO3, and  P) and trace elements (Cu, Zn, and As) in runoff and how the dynamics of litter derived- nutrients in surface runoff can be controlled by using nutrient immobilizing agents.  To address these questions, a greenhouse study was conducted to evaluate and compare the export of bacteria, nutrients and trace elements in surface runoff from pelletized and non-pelletized litter either alone or in combination with immobilizing agents. In this study, strips of sod 19 cm wide and 9 cm deep were cut with a tractor-mounted sod cutter and packed into PVC runoff troughs (146 cm long, 19 cm wide and 10 cm deep) on benches in a greenhouse. Soil in troughs was watered for 10 days to settle into position. Pelletized and non-pelletized poultry litter at the rate of 9 Mg ha-1 alone or in combination with FGD (flue-gas desulfurization) gypsum, a by-product from coal combustion plant, at the rate of 10% by wt. were surfaced applied to the sod strips in the troughs. Sod strips were subjected to simulated rainfall at 3, 14, and 32days after treatment applications.  Runoff water were collected and analyzed. The results will be discussed.