No significant nitrous oxide emissions during spring thaw under grazing and nitrogen addition in an alpine grassland.

摘要

A recent study (Wolf et al., 2010) suggests that short-lived pulses of N₂O emission during spring thaw dominate the annual N₂O budget and that grazing decreases N₂O emissions during the spring thaw. To verify this we conducted year-round N₂O flux measurements from June 2010 to May 2011 in Tianshan alpine grassland in central Asia. No pulse emissions of N₂O were found at grazing management sites and nitrogen addition sites during the spring thaw. The contribution of the spring thaw to the total annual N₂O budget was small and accounted for only 6.6% of the annual fluxes, with winter emissions accounting for 16.7% and growing season emissions accounting for 76.7%. The difference in N₂O emissions attributable to grazing management was not significant (P2O emissions at N addition sites during the grass growing season compared with those at unfertilized sites. N₂O fluxes showed a significant correlation with air temperature and also with both soil temperature and soil water content at 10 cm depth.