Residual Effect of Poultry Litter Applications on No‐Till Cotton Lint Yield

Abstract

In no‐till cotton (Gossypium hirsutum L.) production systems, the potential residual benefits to lint yield from prior years of poultry litter applications are not well known. The objective of this study was to quantify the productivity of no‐till cotton fertilized or unfertilized with synthetic N in years subsequent to the last poultry litter application. Treatments included 3‐ or 6‐yr histories of 0, 2.2, 4.5, or 6.7 Mg ha−1 yr−1 litter; 4.5 Mg ha−1 yr−1 litter plus 67 kg ha−1 yr−1 N as urea‐ammonium nitrate solution(UAN); and 118 or 135 kg ha−1 yr−1 UAN‐N plus inorganic P and K as needed. In subsequent years, cotton was grown with residual from these treatments with or without 135 kg ha−1 yr−1 UAN‐N. Cotton produced up to 25% more lint yield in the first year from the residual of 3‐ or 6‐yr litter applications of 4.5 or 6.7 Mg ha−1 yr−1 relative to residual from synthetic fertilizers. The benefit of a 6‐yr history of 4.5 or 6.7 Mg ha−1 litter application, when followed by fertilization with 135 kg ha−1 UAN‐N, was 12% lint yield increase in the first year. The residual benefit persisted up to 5 yr but was greatest in the first year and diminished with time. The results overall show that including poultry litter as a component of the no‐till cotton fertilization system can enhance cotton production not only in the year of application but also in subsequent years after stopping litter application and resuming conventional fertilization with synthetic fertilizers. Relative to residual from conventional fertilization practices, residual from 3‐ or 6‐yr litter applications of 4.5 or 6.7 Mg ha−1 yr−1 increased cotton lint yield by up to 25%. Cotton planted in soil that has a history of 6 yr of 4.5 or 6.7 Mg ha−1 poultry litter application produced 12% more lint yield in the first year of returning the soil to conventional fertilization with synthetic N fertilizers. The residual benefit of poultry litter on lint yield persisted up to 5 yr but was greatest in the first year and diminished with time.