Poultry Litter Time and Method of Application Effects on Corn Yield

Adopting efficient management practices for using poultry litter (PL) as an alternative to commercial fertilizer is critical for increased N use efficiency. This 3-year study investigated effects of application time (fall and spring) and method of application (soil incorporation and nonincorporation) of three PL rates and NH4NO3 (146 kg N ha(-1)) on availability of selected soil nutrients and corn (Zea mays L.) grain yield in northern Alabama. The plant-available N rates supplied by the PL were 68 kg N ha(-1) (low), 135 kg N ha(-1) (medium), and 270 kg N ha(-1) (high). Soil inorganic N, Mehlich-3-extractable P, and available K were measured before planting in April, mid-season in June or July, and postharvest in October or November. Averaged across the 3 years, grain yield from the high PL rate was similar to that of the medium PL rate when spring applied. The medium PL rate resulted in 800 kg ha(-1) greater grain yield than NH4NO3 from both spring and fall applications. Incorporation of the medium PL rate increased grain yield 590 kg ha(-1) and NH4NO3 by 480 kg ha(-1), respectively, than nonincorporation but no yield advantage of incorporating the low and high PL rates. Inorganic N, Mehlich-3-extractable P, and available K were highest from mid-season sampling and from spring than fall applications. When N sources were incorporated, the medium PL rate resulted in greater N and P uptake. Results from this study suggest that fall application of NH4NO3 and PL beyond the medium rate should not be encouraged for warm climatic conditions.