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.
1United States Department of Agriculture–Agricultural Research Service, 230 Bennett Lane, Bowling Green, Kentucky, USA.
2United States Department of Agriculture–Agricultural Research Service, Mississippi State, Mississippi, USA.
Address for correspondence: Dr. Marcia Jn-Baptiste, P.O. Box 50874, Bowling Green, KY 42102, USA. E-mail: email@example.com
Financial Disclosures/Conflicts of Interest: The authors report no conflicts of interest.
Received September 30, 2012.
Accepted for publication February 26, 2013.