为了揭示节水灌溉对技术对稻田N2O排放的影响,采用静态暗箱—气相色谱法对稻田N2O排放进行了田间原位观测,分析了节水灌溉对稻田N2O季节排放特征的影响.结果表明,水稻全生育期节水灌溉稻田N2O平均排放通量为41.84 μg/(m2·h),较淹水灌溉稻田N2O平均排放通量增加了33.3％；节水灌溉稻田N2O排放总量为119.86 mg/m2,比淹水灌溉稻田显著增加了17.8％；节水灌溉稻田N2O排放通量呈现明显的季节变化规律,有两次较大的排放峰值,峰值主要出现在施肥后1周左右；节水灌溉稻田土壤的每次脱水过程均不同程度地加剧了N2O排放,复水后N2O排放通量有增有减但变幅不大,而淹水灌溉稻田在黄熟期落干阶段N2O排放出现反弹.由此可见,不同灌溉模式下的稻田土壤水分状况决定了N2O季节排放的差异,与淹水灌溉相比,控制灌溉显著增加了稻田N2O季节排放量.%In order to study the effects of water-saving irrigation on seasonal characteristics of N2O emission from paddy fields, N2O emissions from water-saving irrigation paddy fields (WIPF) were investigated by the method of static chamber/gas chromatography. The results showed that the average flux of N2O emissions from WIPF was 41.84 ug/(m2 h), increased by 33.3% compared with that from flooded paddy fields (FPF). The cumulative N2O emission from WIPF was 119.86 mg/m2, increased significantly by 17.8% compared with that from FPF (p<0.05). Seasonal variations of N2O emission from WIPF were obvious. There were two peaks during the rice growing season. These peaks of N2O emissions mainly appeared about 7 days just after fertilizer applications. Soil drying in WIPF incurred N2O emission. Moreover, variations of N2O flux caused by re-flooding were different and the extent of these variations was not large. Soil drying in FPF during the yellow ripeness stage led to the compensation effect of N2O emission. Seasonal variations of N2O emissions from paddy fields under different water managements were depended on soil moisture. Compared with flooded irrigation, the controlled irrigation significantly increased cumulative N2O emission.
展开▼
