Corn Production on a Subsurface-Drained Mollisol as Affected by Fall versus Spring Application of Nitrogen and Nitrapyrin
- Gyles W. Randall * and
- Jeffrey A. Vetsch
Nitrogen management strategies that affect corn (Zea mays L.) production and loss of NO3–N to subsurface, tile drainage often include decisions of when to apply N (fall or spring) and whether to use a nitrification inhibitor. A field study was conducted from the fall of 1993 through 2000 on a tile-drained Canisteo clay loam [fine-loamy, mixed (calcareous), mesic Typic Endoaquolls] to determine the influence of fall vs. spring application of N and nitrapyrin [2-chloro-6-(trichloromethyl) pyridine] on yield of corn and soybean [Glycine max (L.) Merr.] in rotation. Four anhydrous ammonia treatments [fall without nitrapyrin (NP), fall with NP, spring preplant without NP, and spring with NP] were replicated four times and applied at 134 kg N ha−1 (120 lb acre−1) for corn each year. Fall applications occurred between 20 October and 1 November when soil temperatures generally were ≤10°C. Six-year average corn grain yields were least for fall N without NP [10.10 Mg ha−1 (161 bu acre−1)] and greatest for fall N with NP [10.72 Mg ha−1 (171 bu acre−1)], spring N without NP [10.82 Mg ha−1 (172 bu acre−1)], and spring N with NP treatment [11.03 Mg ha−1 (176 bu acre−1)]. Year-to-year variation in yield response to the treatments was great and was characterized by above-normal May rainfall affecting the performance of the fall treatments while above-normal June rainfall affected both fall and spring treatments. Apparent N recovery ranged from 47% for fall N without NP to 61% for spring N with NP. Annual economic return to fertilizer was greatest for spring N with or without NP. Based on the dominating effect of spring rainfall, this study suggests growers consider a spring preplant N strategy either with or without NP as an alternative to fall N for greatest economic return and least N loss to the environment on these Mollisols.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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