Evaluation of Precision Litter Application Practices for Cotton Production and Soil Quality

Placing broiler litter in narrow bands below the soil surface may mitigate losses of litter nutrients and improve plant growth development, yield and quality.  This study was conducted in 2009, 2010 and 2011 to determine the effects of subsurface banding of pelletized litter relative to inorganic fertilizer with FGD gypsum on cotton growth, yield and soil properties under both drip irrigation and non-irrigation systems. A randomized complete block split-split plot design was used in which the main plots were drip irrigation vs. none; split plots were Flue Gas Desulfurization gypsum vs. none and split-split plots were inorganic fertilizer (120 lb N/ac, pelletized litter (6.7 Mg/ha) and unfertilized control. Each plot had six rows spaced 0.97 m apart and about 27 m long.  FGD gypsum applied broadcast at the rate of 2.2 Mg/ha. A GPS-guided tractor was used to plant cotton, apply the pelletized litter and side dress the N fertilizer in precise subsurface bands so that the seed and fertilizers are placed in exactly the same place year after year.  Initial soil samples were taken and analyzed for chemical and biological properties. At peak blooming total 20 leaves were taken randomly from the two middle rows for N concentration. Leaf chlorophyll content was also measured using hand held SPAD meter. At open boll stage, whole plant samples were taken from 50 cm in row, bolls were separated, dried separately, ground and analyzed for nutrient concentrations. Before harvesting, plant fruiting maps at end of season to measure time scale of boll setting. All six rows were harvested using a two row picker and yield was determined. End-season soil samples were taken after harvest and analyzed for physical, chemical and biological properties. Detailed information related to the effects of treatments on cotton yield, nutrient utilizations and soil properties will be discussed.