Evaluation of the Effects of Poultry Litter Applications On Cotton Yields, Soil Nutrients, and Runoff in Northeast Louisiana.

Cotton has been the dominant crop in northeast Louisiana for decades.  However, due to many years of continual intense cotton production, these fields have declined in many soil properties.  The application of poultry litter as soil amendment could potentially alleviate these problems.  However, little information is available on the effect of poultry litter application on these highly degraded soils.  Therefore, a field trial was conducted to evaluate the effect of poultry litter applications within both conventional and conservation tillage systems.  Trials were conducted from 2008 through 2011 in Winnsboro, Louisiana.  Poultry litter was applied at the rate of 0, 3.3, and 6.7 Mg ha^-1.  Litter applications were evaluated over both conservation and conventional tillage operations as well as with and without a winter cover crop.  Additionally, a treatment which fertilizer was applied through inorganic sources under conventional tillage systems was included to simulate standard production practices.  Throughout the growing season runoff was collected using flume sampler during rainfall and irrigation events to measure the P runoff from each plot.  Following harvest, soil samples were collected and total soil analysis was conducted.  Cotton lint yields of the poultry litter treatments were significantly (P<0.05) higher than those that received solely inorganic fertilizers by an average of 250 kg lint ha^-1.  Additionally, poultry litter applied treatments that were incorporated yielded lower soluble and total P in first flush run-off events compared to unincorporated and inorganically applied P treatments.  Further, a significant build-up of Mehlich-3 extractable P was evident for poultry litter applied treatments compared to the check plots; however, there was no evident effect of poultry litter application on extractable P build-up compared to inorganic P applications.   Poultry litter can be used as a soil amendment in northeast Louisiana, especially on the highly degraded to improve their productivity as well as sustainability.