用封闭箱法原位观测几种旱田Ｎ２Ｏ的排放通量，并与裸地Ｎ２Ｏ通量比较，评价植物在农田Ｎ２Ｏ释放中的作用．田间观测与室内模拟实验结合，考察环境因子对Ｎ２Ｏ通量的影响．结果表明１ｄ内大豆田Ｎ２Ｏ通量有两个释放高峰，而菠菜田和春小麦田只有１个释放高峰．种植大豆较大地提高了农田Ｎ２Ｏ的排放通量．农田裸地为一较弱的Ｎ２Ｏ释放源，且在１年的一定时期内表现为大气Ｎ２Ｏ的汇．光照变化对植物Ｎ２Ｏ通量影响很大，在较弱的光照条件下，植物释放Ｎ２Ｏ的通量较高． The closed-chamber method was used to observe the N 2 O flux in situ and compare with the bare N 2 flux to evaluate the role of plant in the N 2 O release from farmland. Field observations and laboratory simulation experiments combined with environmental factors on the impact of N2O flux. The results showed that N2O fluxes in soybean field had two release peaks in 1d, while only one release peak in spinach and spring wheat fields. Planting soybeans greatly increased N2O emissions from farmland. Cropland bare land is a weaker source of N2O and represents a sink of atmospheric N2O for a period of one year. The change of illumination has a great influence on the N2O flux of plants, and under the weak illumination conditions, the flux of N2O released by plants is higher.