Seasonal Anhydrous Ammonia Comparison for Corn With and Without a Nitrification Inhibitor1

Abstract

AbstractWith increased interest in “off‐season” N application and emphasis on better management of N with respect to environmental pollution and economic considerations, information is needed relative to seasonal anhydrous ammonia comparisons for corn with and without an inhibitor.Field studies compared rates of N applied preplant with December application either with or without the nitrification inhibitor, N‐SERVE (2‐chloro‐6‐(trichloromethyl) pyridine), to corn (Zea mays L.) on a Coastal Plain soil. The nitrification inhibitor (NI) did not affect yield, number of ears, average ear weight, and percent N, P, K, Ca, and Mg in the tissue or concentrations of various other elements in tissue sampled early in the growing season, at early silking, or in corn grain. Both low (90 kg/ha) and high (180 kg/ha) N levels increased yields above check plots (zero N) when applied in December for the three‐year average but both levels were significantly less than the high N level applied preplant. Ears per plant and ear weight were closely related to yields. Yield was more closely related to percent N in the tissue sampled at silking than tissue sampled early (ca 20‐cm height) or percent N in the grain.On a 3‐year average, the low and high N rates applied in December were 84 and 82% as efficient as preplant applications.These studies indicate that “off‐season” N applications as anhydrous ammonia are not as efficient as preplant applications. The NI did not influence micronutrient levels in the plant tissue, although N rates and time of application affected Mn, Fe, and Zn levels.