Nitrous Oxide Emissions from a Fallow Field Fertilized with Anhydrous Ammonia1
- V. L. Cochran,
- L. F. Elliott and
- R. I. Papendick2
Nitrous oxide emission was measured from fallow Palouse silt loam (fine-silty, mixed, mesic pachic Ultic Haploxerolls) fertilized with 0, 55, 110, and 220 kg of N ha−1 as anhydrous NH3. The objective was to quantify N2O losses during nitrification of banded anhydrous NH3 under field conditions. Maximum N2O emission occurred shortly after initiation of rapid nitrification. Nitrites were present in the center of the NH3 retention zone during N2O emission from the 110 and 220 kg N ha−1 treaments but not in the retention zone of the check or 55 kg N ha−1 treatments. Cumulative N2O emission increased as the NH3 rate was increased, but was disproportionately large from the 220 kg N ha−1 treatments. However, even at the high N application rate, which was twice that recommended for the alternate winter wheat-fallow area of the Pacific Northwest, less than 0.1% of the applied N was recovered as N2O. Recovery of applied NH3 in the mineral form was approximately 100, 100, and 80%, respectively, for the 55, 110, and 220 kg N ha−1 treatments 5 weeks after application, suggesting that at the higher N rate N losses may have occurred via mechanisms other than N2O.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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