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Post-Anthesis Nitrogen Loss from Corn

Author:
Francis, D. D., Schepers, J. S., Vigil, M. F.
Source:
Agronomy journal 1993 v.85 no.3 pp. 659
ISSN:
0002-1962
Subject:
Zea mays, flowering, irrigated conditions, nitrogen fertilizers, nitrogen, nutrient uptake, leaves, stems, volatilization, losses from soil, leaching, denitrification, application rate, grains
Abstract:
Published research has shown relatively large amounts of NH being lost from aboveground vegetation during grain development for various grain crops For corn (L.), maximum net N accumulation usually occurs during early reproductive development (R1-R3) and a subsequent decline is often observed. Two recently completed N fertilizer recovery studies on irrigated corn utilizing isotopic techniques were re-examined to quantify post-anthesis N losses from aboveground biomass of irrigated corn under different N regimes. These studies were conducted at different sites, in different years, with fertilizer rates ranging from 50 to 300 kg N ha−. Measured losses of labeled N from aboveground plant material ranged from 7 to 34 kg N ha−. Isotopic dilution suggests that apparent real N losses from aboveground biomass ranged from 45 to 81 kg N ha−, assuming there is no selectivity for N source (i.e., N vs. N). Plant N losses accounted for 52 to 73% of the unaccounted-for N in N balance calculations. Failure to include direct plant N losses when calculating an N budget leads to overestimation of losses from the soil by denitrification, leaching, and ammonia volatilization. Proper accounting for volatile plant N losses may improve management strategies that affect N fertilizer use efficiencies.
Agid:
17158
Handle:
10113/17158