Nutrient Losses During Temporary Field Storage of Poultry Litter.

Temporary storage of poultry litter in fields after removal from the poultry production facility prior to spreading as a fertilizer is a common practice in the Delmarva region. There has been some concern, however, on the potential losses of nutrients to the environment during this field storage. The objectives of this project were to quantify the types and amounts of nutrients being lost from these piles during storage. Production-size piles were utilized for this project, because all previous research has used small research-size piles that may not adequately compare to actual practices used in production agriculture. Our results indicate that if a stockpile size of about 100 tons of litter is assumed, then the amounts of inorganic N (i.e., ammonium-N + nitrate-N) found in the underlying soil following litter storage ranged from 2 to 29 pounds with a mean of 12 pounds. Covering the piles with polyethylene resulted in no significant reduction in N losses from the piles into the underlying soil. Soluble salt levels in the surface layer of the soil following poultry litter storage usually prevented establishment of crops in the area were the litter was piled. Covering the pile with polyethylene did not reduce the amounts of soluble salts found in the soil. The nutrient lost in the greatest amounts from poultry litter piles was potassium followed by sulfur. Regression analysis showed that these two nutrients were the main contributors to high levels of soluble salts, and inorganic N levels had only small insignificant impacts on soluble salt concentrations. The poultry litter piles had only minimal impacts on soil test phosphorus concentrations. Overall, the results from this project showed that amounts of N lost from temporary piles of poultry litter were quite small and represented about 0.2% of the amount of N in the litter pile.