菜地系统土壤氧化亚氮排放的日变化

Daily change of nitrous oxide emission from vegetable system

采用原状土柱试验,研究了武汉市菜地连作系统不同时期土壤N2O释放日变化特征及其与土壤温度和水分的关系。结果表明:当土壤水分日变化较小时,土壤N2O排放速率随土壤温度的升高而增大,随着温度的降低而减小,在温度最高时达到峰值;而当土壤水分日变化较大时,N2O排放速率峰值出现在适宜的水分且较高的温度时,而非温度最高时。这说明土壤N2O排放速率受土壤温度和土壤水分共同影响。同时,氮肥施用量也是影响N2O日排放的重要因子。

Undisturbed soil monolith lysimeters were conducted to study daily nitrous oxide（N2O） emission and its relationship with soil temperature and water content in a continuous vegetable cropping system in Wuhan.Results showed that N2O daily emission increased with the increase of soil temperature and the peak emission occurred at the highest temperature when soil moisture was relatively stable.However,when soil moisture changed rapidly in one day,the peak emission of N2O occurred at appropriate soil moisture and relatively high soil temperature,meaning that both soil moisture and temperature affected the daily change of N2O emission in this vegetable system.Nitrogen fertilizer was found to be another important factor in affecting daily N2O emission.