Cotton Response to Broiler Litter in a Corn-Cotton Rotation System.

Poultry litter has proven to be an effective cotton (Gossypium hirsutum L.) fertilizer under conventional and no-till systems in silt loam soils in Mississippi. It may also prove to be a valuable fertilizer in heavier soils where cotton is typically rotated with corn (Zea mays L.) or other crops to maintain productivity.  The objective of this research was to determine the effectiveness of poultry litter in continuous cotton compared with corn-cotton rotation in a heavy soil in northern Mississippi.  The research was conducted at the Northeast Branch Experiment Station of Mississippi State University, Verona, MS in a Catalpa silty clay loam soil (Fine, smectitic, thermic Fluvaquentic Hapludolls).  Three main plots with the sequence cotton-cotton-cotton, cotton-corn-cotton, and corn-cotton-cotton in Year 1, Year 2, and Year 3 were split into five subplots each of which received 0, 4.5, 9.0, 13.5 Mg litter ha^-1 or 123 kg N/ha as urea-ammonium nitrate solution with 32% N (UAN).   The results showed that, unlike soils in other locations where approx 9.0 Mg/ha or less litter was adequate to produce equal yield as standard inorganic fertilization, cotton in this soil responded to as much litter as 13.5 Mg/ha. Cotton that followed cotton tended to yield better than cotton that followed corn when applied litter was 9.0 Mg/ha or less.  This suggests corn depleted more soil nutrients than cotton and there were less residual nutrients including N when cotton followed corn than when cotton followed cotton. Applying approx 13.5 Mg/ha litter to corn resulted in equal grain yield as applying 180 kg/ha UAN-N.