Soil N2O discharge flux of mulch was higher than that of no mulch treatment, and with the depth of 5, 10, 20cm the soil N2O discharge flux and the net adding flux increased in the order of depth in the upper soil layers.

• 3 地膜覆盖使5，10，20cm土层处N_2O的排放通量较未覆膜处理显著增加，且随着土层的加深，排放量依次增大，增加幅度也表现为下层大于上层。