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

Abstract

In temperate regions, a majority of N 2O 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 N 2O 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 N 2O fluxes (73.3 vs. 57.9 ng N 2O–N cm −2 h −1). The rye cover had no effect on N 2O emissions. The second season (2007–08) was a much milder winter (1271 h below freezing at 8 cm soil depth), with lower N 2O fluxes overall. The winter rye cover resulted in lower N 2O fluxes (5.9 vs. 33.7 ng N 2O–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 N 2O emissions can be expected to decrease and could be further reduced by winter rye crops.