Soil nitrous oxide and methane data for South slope of Niwot Ridge, 1992.

To determine the effect of increased nitrogen availability on fluxes of N2O and CH4 from alpine soils, we measured fluxes of these gases from fertilized and unfertilized soils in two alpine plant communities differing in net primary productivity, soil organic matter quality, and moisture. Five fertilized and 5 unfertilized plots within each community type were sampled. In the dry meadow community, the addition of nitrogen resulted in a 22-fold increase in N2O emission, while in the wet meadow, we observed a 45-fold increase in N2O emission rates. Methane uptake in the dry meadow community was reduced 52% by fertilization. However, net CH4 production occurred in all of the wet meadow plots and emission rates were not significantly affected by fertilization. Net nitrification rates were higher in dry meadow fertilized plots than in non-fertilized plots throughout the growing season. Net mineralization rates in fertilized dry meadow plots were higher than those in non-fertilized plots during the latter half of the growing season. Carbon to nitrogen ratios and amounts of total soil organic nitrogen in both the wet and dry meadow were not significantly affected by fertilization.