ABSTRACT
Collectively, methane (CH4) and nitrous oxide (N2O) are responsible for about 20% of the global warming. These two gases are increasing in the atmosphere at annual rates of 1.1 and 0.3%, respectively. Both are produced by microbial activity in soil and are influenced by man's activities. This chapter quantifies the flux of N2O and CH4 gases in subarctic agricultural soils. It evaluates the effects of nitrogen (N) fertilizer on long term and short term consumption of CH4 by soil in permanent grass. Two sites were selected in areas which had been in grass for 10 or more years to monitor the effects of urea application on CH4, and N2O flux. One site was on Fairbanks silt loam with a south facing slope of about 15%. The other site was a Tanana silt loam with less than 1% slope and had been in smooth brome grass hay production for 10 or more years and received about 90 kg N ha-1 yr-1.
