Soil with a Short History of Poultry Litter Fertilization Remains Superior to Normally Fertilized Soil for Cotton.

Potential residual benefits from several years of poultry litter application to row crop soils, after returning the soils to conventional inorganic fertilization, are unknown.  This study investigated the productivity of cotton in a silt loam soil 1 yr after stopping six consecutive years of litter application.  Lint yield of cotton fertilized with 135 kg/ha N as urea-ammonium nitrate (UAN) was measured in soils that had received 0 to 6.7 Mg/ha broiler chicken litter in the previous 6 yr.  The cotton planted in a soil with 6 yr history of 4.5 or 6.7 Mg/ha litter fertilization produced >9% more lint than the one with 6-yr history of conventional inorganic fertilization. Lint yield in a soil that had been severely depleted from 6 yr of no fertilization was 18% less than lint yield of a continuously fertilized soil although both received the 135 kg/ha UAN-N.  The results demonstrated that soils with a short history of even suboptimal litter rate fertilization were more productive when returned to conventional fertilization than soils with continuous conventional inorganic fertilization.