Nutrient Uptake of ‘Jesup MaxQ' Tall Fescue Fertilized with Broiler Litter.

In tall fescue (Festuca arundinacea Schreb.), the nutrients derived from organic or inorganic sources can affect forage production in various ways, including seasonal and total availability of macronutrients and secondary nutrients, and interaction with endophyte-produced metabolites, alkaloids, that can reduce animal performance.  The novel-endophyte infected cultivar, Jesup MaxQ, has little or no ergot alkaloid production.  This field study determined nutrient uptake by Jesup MaxQ and changes in soil chemical parameters in response to five litter rates (0, 4.48, 8.96, 13.44, and 17.92 Mg ha^-1) and a commercial fertilizer (CF) 'check' that provided 224, 112, and 224 kg ha^-1 of N, P, and K, respectively.  Manure and fertilizer were split-applied in April and October 2005-2007 to small plots (2 x 5 m) that were randomized in a complete block design with four replicates.  Plots were harvested in April, May and October, and soil sampled in April at 0-5, 5-15, and 15-30 cm depths.  Averaged across years, annual N uptake averaged 140 kg ha^-1 with CF and increased quadratically from about 35 to 147 kg ha^-1 across litter rates (r²=0.99).  The percentage of N recovered (adjusted for unfertilized controls) averaged 47% with CF, much higher than the 14-27% range observed across the four litter rates.  Analysis of 0-15 cm soil depth in April 2007 found Mehlich-3 extractable P averaged 62 mg kg^-1 with either CF or 4.48 Mg ha^-1 litter, the value increased to 77 mg kg^-1 with 8.96 Mg ha^-1 litter, and averaged about 113 mg kg^-1 in the two highest litter rates.  Broiler litter appeared to improve forage production in summer months, though litter rates exceeding 8.96 Mg ha^-1 may cause a rapid accumulation of P and other nutrients in soil.