Corn Production on a Subsurface‐Drained Mollisol as Affected by Time of Nitrogen Application and Nitrapyrin

Abstract

Time of N fertilizer application to corn (Zea mays L.) and use of a nitrification inhibitor are management strategies that can affect corn production and loss of NO3–N from the soil profile via subsurface, tile drainage. A field study was conducted from the fall of 1986 through 1994 on a tile‐drained Canisteo clay loam soil [fine‐loamy, mixed (calcareous), mesic Typic Endoaquolls] to determine the influence of time of N application and nitrapyrin [2‐chloro‐6‐(trichloromethyl) pyridine] on yield of corn and soybean [Glycine max (L.) Merr.] in rotation and N uptake of corn. Four anhydrous ammonia (AA) treatments [(fall without nitrapyrin (NP), fall with NP, spring preplant, and split (40% preplant and 60% sidedress at V8 stage)] were replicated four times and applied at 150 kg N ha−1 (135 lb N acre−1) for corn each year. Fall applications occurred between 19 and 28 October when soil temperatures generally were ≤10°C. Seven‐year average corn grain yields were least for fall N without NP (8.27 Mg ha−1, 131 bu acre−1), intermediate for fall N with NP and spring N (8.72 Mg ha−1, 139 bu acre−1), and greatest for the split N treatment (9.11 Mg ha−1, 145 bu acre−1). Corn N uptake was not different among treatments in drier years but was generally greatest for the spring and split treatments in wet years. Apparent N recovery ranged from 31% for fall N without NP to 44% for the split treatment. Economic return to fertilizer was greatest for the split treatment ($239.40 ha−1 yr−1) and lowest for fall N without NP ($166.70 ha−1 yr−1). Application time strategies for AA considered to be best management practices for these poorly drained Mollisols include fall N with NP, spring preplant, and split application.