Greenhouse Evaluation of the Agronomic Efficiency of Anhydrous Ammonia
1966
Parr, J. F. | Papendick, R. I.
Three greenhouse pot experiments were conducted with corn grown on Mountview loam and Hartsells fine sandy loam to (a) measure the relative agronomic effectiveness of direct applications of anhydrous NH₃, as influenced by preplan! incubation period and schedule of application, and (b) to determine the influence of soil moisture content at time of NH₃ injection on crop response to anhydrous NH₃. Response of corn to anhydrous NH₃ tended to be less than to an ammonium N source with shorter incubation periods, but was generally as effective as a nitrate N source except when high N rates were applied at planting. In the latter case, yields were somewhat reduced. When anhydrous NH₃ was injected into the soil-root zone according to different application schedules, corn yields were considerably reduced at the higher N levels when compared to equivalent applications of urea and NH₄NO₃. Yield reduction in these cases was attributed in part to root damage due to NH₃ toxicity, and possibly to temporary positional unavailability of the applied N. Soil-cultured corn plants, however, appeared to be remarkably tolerant to high levels of anhydrous NHs when applied directly into the root zone. A small but consistent decrease in yield was observed when high levels of anhydrous NH₃ were applied to soils in an air-dry rather than moist condition.
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