Herbage Nutritive Value of Tall Fescue Fertilized with Broiler Litter and Inorganic Fertilizer

The nutrients in broiler litter can replace inorganic fertilizer additions, but must be managed to minimize soil nutrient build-up and off-site losses in the environment. Herbage dry matter (DM) and nutritive value were measured in tall fescue at litter rates of 0, 4.5, 9.0, 13.5, and 18.0 Mg/ha/year, as compared to inorganic fertilizer (INORG) that provided N, P₂O₅, and K₂O (224-112-224 kg/ha/year), in soil with no litter history. The treatments were split-applied in autumn and spring, and forage was harvested at early-, mid-, and late-season. In general, nutritive value was greatest at early-season, based on low acid detergent fiber (ADF) and high in vitro true digestible DM (IVDDM). Herbage crude protein (CP) was similar in INORG and 9.0 Mg litter per ha at the early- and late-season harvests, with litter producing CP values of 105 to 125 g/kg. The litter effect was significant at late season in 2006, when CP increased approximately 42 g/kg, ADF decreased 35 g/kg, and neutral detergent fiber (NDF) decreased 30 g/kg. The use of 9.0 Mg litter per ha produced forage with reasonably high DM yield and nutritive value, but elevated soil P, Cu, and Zn, as compared to INORG and 4.5 Mg litter per ha. Herbage nutritive value was generally lower at 4.5 Mg litter per ha than INORG, but both fertilizer sources appeared to minimize potential risks to the environment when tall fescue was grown for hay.