[N2O flux in winter and its affecting factors under different land use patterns]

Due to the low temperature in winter, the emissions of greenhouse gas are often neglected. And the latest research results showed that there is continuous N2O emission in winter, therefore, research on understanding the No2O flux regulation is important for evaluating agricultural soil N2O emission. By using static chamber techniques, the N2O emission from soils under different land use patterns including fallow paddy field, rape cropping, honey pomelo orchard and abandon land in Taoyuan agricultural ecological experimental station of Chinese Academy of Sciences was measured. The results showed that fallow paddy field and rape cropping N2O emissions were obviously higher than those of the honey pomelo orchard and abandon land, and the total N2O flux in winter decreased in the order of rape cropping > fallow paddy field > honey pomelo orchard > abandon land. Cumulative N2O emission was 0.502, 0.392, 0.162 and 0.075 kg x hm(-2), respectively. Fallow paddy field and rape cropping N2O emissions accounted for large proportions of the annual N2O emissions, while honey pomelo orchard and abandon land had small contribution to the annual N2O emissions. The correlation analysis results showed that for different land use patterns, when the soil temperature > 5 degrees C, N2O emissions in winter and soil temperature had significant positive exponential correlation, and had little to do with moisture. This research showed that: when the soil temperature > 5 degrees C, the soil temperature was the leading factor in N2O emissions in winter under different land patterns; When the soil temperature < 5 degrees C, other environmental factors had comprehensive influences on the N2O emissions.