Wednesday, November 15, 2006

Uptake Efficiency of Broiler Litter-Derived Macronutrients by Cotton.

Haile Tewolde1, Karamat Sistani2, Dennis Rowe2, and Ardeshir Adeli3. (1) USDA-ARS-NPA-SPNRU, USDA-ARS, 810 Hwy. 12 E, Mississippi State, MS 39762-5367, (2) USDA-ARS, 230 Bennett Lane, Bowling Green, KY 42104, (3) USDA-ARS Waste Mngmnt & Forage, 810 Hwy 12 East, 810 Hwy 12 East, Mississippi State, MS 39762, United States of America

Effective management of litter to minimize or prevent the buildup of nutrients to detrimental levels in the soil requires knowledge of the amount of nutrient extracted and removed by harvested crop.  However, this knowledge for cotton does not exist or is not well documented when litter is used as a primary cotton fertilizer.  A field research was conducted at two locations in Mississippi that represent conventional- and no-till systems to determine the efficiency of cotton in extracting N, P, K, Mg, and Ca derived from broiler litter.  End-of-season extraction efficiency of the macronutrients was computed as total extracted amount divided by total applied after accounting for nutrients supplied by the soil reserve. When averaged across all treatments and years, the extraction efficiency of N, P, K, Ca, and Mg, respectively were 44, 17, 47, 43, and 36% of the applied.  However, application of broiler litter and inorganic N supplied as urea ammonium nitrate solution (UAN) significantly affected the extraction efficiency. Increasing rate of applied litter decreased uptake efficiency while supplemental inorganic N increased extraction efficiency of all macronutrients.