A labama ranks third in the nation in broiler production, marketing 921.8 million birds in 1999. The industry processes about 18 million broilers a week, and these broilers produce more than 2 million tons of litter each year. Broiler litter is most often disposed of by application to local agricultural land, especially pasture and hay fields, due to hauling expenses. Although litter is a beneficial source of plant nutrients, long-term application can lead to degradation of surface water quality. Phosphorus is considered to be the limiting nutrient causing freshwater eutrophication.
Eutrophication occurs when nutrient input to surface water causes increased algae production.
Overabundance of algae depletes oxygen from water and increases turbidity, or cloudiness, which, in turn, increases the potential for fish kills, growth of toxic cyanobacteria, and poor drinking water quality. The waters used for fisheries, industry, drinking, and recreation may all be negatively affected. Many watersheds in Alabama are at risk for surface water degradation due to long-term application of manure with high amounts of P. Tillage practices have been shown to have a significant impact on surface water quality, affecting both P concentrations and losses. An AAES study was initiated to look at the impact of tillage on P in soils overloaded with broiler litter. Soils were analyzed for total and inorganic extractable P. Conservation tillage, which leaves a significant amount of residue and fertilizer on the soil's surface, is promoted for purposes of reducing soil erosion.