The influence of winter soil cover on spring nitrous oxide emissions from an agricultural soil

In temperate regions, a majority of N2O is emitted during spring soil thawing. We examined the influence of two winter field covers, snow and winter rye, on soil temperature and subsequent spring N2O emissions from a New York corn field over two years. The first season (2006–07) was a cold winter (2309 h below 0 °C at 8 cm soil depth), historically typical for the region. The snow removal treatment resulted in colder soils and higher N2O fluxes (73.3 vs. 57.9 ng N2O–N cm−2 h−1). The rye cover had no effect on N2O emissions. The second season (2007–08) was a much milder winter (1271 h below freezing at 8 cm soil depth), with lower N2O fluxes overall. The winter rye cover resulted in lower N2O fluxes (5.9 vs. 33.7 ng N2O–N cm−2 h−1), but snow removal had no effect. Climate scenarios predict warmer temperature and less snow cover in the region. Under these conditions, spring N2O emissions can be expected to decrease and could be further reduced by winter rye crops.