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This article in JEQ

  1. Vol. 37 No. 2, p. 542-550
     
    Received: Sept 22, 2006
    Published: Mar, 2008


    * Corresponding author(s): rengel@montana.edu
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doi:10.2134/jeq2006.0395

Nitrous Oxide Emissions from a Northern Great Plains Soil as Influenced by Nitrogen Management and Cropping Systems

  1. M. P. Dusenburya,
  2. R. E. Engel *a,
  3. P. R. Millera,
  4. R. L. Lemkeb and
  5. R. Wallandera
  1. a Dep. of Land Resources and Environmental Sciences, Montana State Univ., P.O Box 173120, Bozeman, MT 59717-3120
    b Agriculture and Agri-Food Canada, 51 Campus Drive, Saskatoon, SK S7N 5A8

Abstract

Field measurements of N2O emissions from soils are limited for cropping systems in the semiarid northern Great Plains (NGP). The objectives were to develop N2O emission-time profiles for cropping systems in the semiarid NGP, define important periods of loss, determine the impact of best management practices on N2O losses, and estimate direct N fertilizer-induced emissions (FIE). No-till (NT) wheat (Triticum Aestivum L.)-fallow, wheat-wheat, and wheat-pea (Pisum sativum), and conventional till (CT) wheat-fallow, all with three N regimes (200 and 100 kg N ha−1 available N, unfertilized control); plus a perennial grass-alfalfa (Medicago sativa L.) system were sampled over 2 yr using vented chambers. Cumulative 2-yr N2O emissions were modest in contrast to reports from more humid regions. Greatest N2O flux activity occurred following urea-N fertilization (10-wk) and during freeze–thaw cycles. Together these periods comprised up to 84% of the 2-yr total. Nitrification was probably the dominant process responsible for N2O emissions during the post-N fertilization period, while denitrification was more important during freeze–thaw cycles. Cumulative 2-yr N2O-N losses from fertilized regimes were greater for wheat-wheat (1.31 kg N ha−1) than wheat-fallow (CT and NT) (0.48 kg N ha−1), and wheat-pea (0.71 kg N ha−1) due to an additional N fertilization event. Cumulative losses from unfertilized cropping systems were not different from perennial grass-alfalfa (0.28 kg N ha−1). Tillage did not affect N2O losses for the wheat-fallow systems. Mean FIE level was equivalent to 0.26% of applied N, and considerably below the Intergovernmental Panel on Climate Change mean default value (1.25%).

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Copyright © 2008. American Society of Agronomy, Crop Science Society of America, Soil Science SocietyAmerican Society of Agronomy, Crop Science Society of America, and Soil Science Society of America