Effects of bedding materials in applied poultry litter and immobilizing agents on runoff water, soil properties, and bermudagrass growth.

Poultry producers in the United States have begun using different types of bedding materials in production houses. Release into the environment of nutrients from applied poultry litter (PL) made with different bedding materials has not been investigated, and little information is available on nutrient concentrations in soils that receive broiler litter made with such materials. In this greenhouse study, two bedding materials (rice hulls and pine chips) in PL and 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. Treatments with rice hull bedding material in PL had less runoff nutrient and greater soil soluble N and P compared with pine chip bedding. Gypsum and biochar both significantly reduced C, N, P, Cu, and Zn losses from the first runoff event, which were reduced by 26, 30, 37, 38, and 38% and by 25, 24, 30, 29, and 35%, respectively, but only gypsum obviously reduced these nutrients from later events. Potassium, Ca, Mg, and Mn increased by 2, 36, 11, and 9 times, respectively, and soluble P, Cu, and Fe significantly decreased by 68, 72, and 98%, respectively, in soil amended with gypsum. Rice hull PL in combination with gypsum significantly increased the growth of bermudagrass. Our results indicate that rice hull PL posed less risk for nutrient loss than pine chip PL when applied to fields and that gypsum was better than biochar for reducing runoff C, N, P, and Cu.