黄淮海平原典型农田土壤N2O的排放特征-生物通.doc

黄淮海平原典型农田土壤N2O的排放特征 王立刚，李 虎，邱建军 （中国农业科学院农业资源与农业区划研究所，北京 100081） 摘要：【目的】明确黄淮海平原地区典型作物种植类型下，农田土壤N2O排放特征，并探明不同环境因子对其排放通量的影响。【方法】采用静态箱法测定了黄淮海平原典型农田（冬小麦/夏玉米、棉花、休闲地）土壤N2O的排放通量及其季节变化特征，并分析了土壤温度、土壤水分、不同氮肥量对土壤N2O通量的影响。【结果】3种种植方式N2O排放在秋季均呈现总体下降趋势，至12月中旬左右降到最低，随着春季气温的升高则呈总体上升趋势。冬小麦/夏玉米地土壤N2O排放高峰值为433.5 μg N2O·m-2·h-1，出现在7月下旬；棉花地为146.5 μg N2O·m-2·h-1，出现在6月中旬；休闲地为175.16 μg N2O·m-2·h-1。在棉花地和休闲地，N2O排放通量随地温增加而呈指数增长，而在冬小麦/夏玉米地则没有观测到N2O排放通量与地温之间的相关关系，但与土壤含水量的变化趋势基本一致。施用氮肥对土壤N2O的排放具有明显的促进作用。【结论】N2O排放表现出多峰的日变化特征，呈明显的季节变化；土壤中N2O的产生与释放受多种环境因子的影响，而且不同环境条件不同作物影响因子所起的作用是不一样的。 关键词：N2O；黄淮海平原；农田土壤 Characterization of Emissions of Nitrous Oxide from Soils of Typical Crop Fields in Huang-Huai-Hai Plain WANG Li-gang, LI Hu, QIU Jian-jun (Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081) Abstract: 【Objective】characterization of N2O emissions from different crop types fields, and to study the impact of different factors on N2O emissions. 【】he influence of soil temperature and moisture on soil N2O flux was also discussed. 【】the peak value of N2O emission flux appeared in July with 433.5 μgN2O·m-2·h-1 in winter wheat–summer corn rotation fields, 146.5 μg N2O·m-2·h-1 in cotton fields (the peak value appeared in June) and 175.16 μg N2O·m-2·h-1 in fallow fields. The N2O emission was exponentially correlated with the soil moisture, but it did not happen in wheat–summer corn rotation field. The more N2O emissions also occurred in the fields with higher nitrogen fertilizer. 【】The emission and production of N2O was influenced by many factors, and also different factors made different impact on the N2O emissions. Key words: N2O; Huang-huai-hai Plain; Cropland soils 0 引言 氧化亚氮（N2O）是重要的温室气体之一，主要来自土壤中微生物的硝化、反硝化作用、海洋、工业生产、生物质燃烧，N2O的汇主要是平流层的光解作用[1]。农田土壤作为大气N2O重要的源一直受到研究者的普遍关注[23]。据研究农田土壤中微生物参与下的硝化和反硝化过程所释放的N2O，约占生物圈释放到大气中N2O总量的70%～90%[4]。国农业氧化亚氮排放量约占全球总排放量的1.0%～1.5%[5]，且年排放量呈增加趋势。许多研究表明，农田土壤N2O排放有明显的日变化和季节变化规律[68]，氮肥施用水平、土壤温度、湿