Title: Effects of bedding materials in applied broiler litter and immobilizing agents on runoff water, soil properties, and bermudagrass growth Authors
Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 3, 2012
Publication Date: N/A
Interpretive Summary: Broiler chicken production is a major agricultural industry in the southeastern USA, and more than two-thirds of the total U.S. production originates in this region. The broiler production facilities throughout the Southeast generate broiler litter (a mixture of bedding material and manure) widely available there. As costs of chemical fertilizers rise, broiler litter becomes increasingly viewed and utilized as an alternative and inexpensive source of fertilizer. Surface broadcast is currently the most commonly used method for applying PL, but this practice concentrates nutrients and pathogenic microorganisms at the soil surface where they more readily enter runoff water. Broiler litter applied in the field may contain a variety of bedding materials. Wood shavings and sawdust have been most commonly used as bedding in commercial production. However, when these materials are in short supply or only available at a high cost, producers may use rice hulls, wheat straw, and sand as substitute bedding materials. Previous research on use of different bedding materials has focused mainly on broiler performance. However, The effects of bedding materials on the potential releasing of nutrients and pathogen from broiler litter into the environment have not been well investigated. The objective of this study was to determine the effects of pine chips and rice hulls bedding materials in applied broiler litter on nutrient concentrations and microbial population levels in runoff and to compare the efficacy of FGD gypsum and biochar in reducing levels of nutrients in runoff water.
Technical Abstract: Recently poultry producers in the USA have begun using different types of bedding materials in production houses. Nutrient release into the environment from applied broiler litter (BL) made with different bedding materials has not been investigated. In this greenhouse study, broiler litter (BL) with two bedding materials (rice hulls and pine chips) in mixing with two nutrient immobilizing agents (gypsum and biochar), were applied to bermudagrass, and chemical and microbial contents of runoff water, soil properties, and plant growth were evaluated. Simulated rainfall applied to strips of bermudgrass (Cynodon Doctylon L.) to which different combinations of bedding materials in BL and immobilizing agents were applied. Treatments with pine-chip bedding material in BL had greater nutrient concentrations in runoff water than did those with rice hulls. Gypsum and biochar both reduced C, N, P, K, Cu, and Zn concentrations in water from the first runoff event. Gypsum also lowered concentrations of these nutrients in water from later events but biochar did not. In addition, population levels of Enterococcus in runoff water were reduced by gypsum while levels of Staphlococcus were not affected by any treatments. Results indicate that rice-hull poses less risk for nutrient loss in runoff water following its application to soil than dose with pine-chip. In addition, gypsum is likely to be a better immobilizing agent than biochar for reducing amounts of C, N, P, and Cu, as well as Enterococcus population levels in runoff water from fields fertilized with broiler litter.