水分管理与秸秆施用对稻田CH4和N2O排放的影响

2000年6~10月在南京近郊江宁区实施大田试验.主要研究了水稻生长季常规灌溉和连续淹水条件下有机质(小麦秸杆)不同施用量(0,2.25,4.5t/hm2)对稻田CH4和N2O排放的影响.结果表明,在连续淹水条件下,CH4排放量与秸杆施用量成正比,N2O排放与秸杆施用量成反比.烤田的N2O的排放量在施用2.25t/hm2秸杆与对照之间无明显差异,但施用4.5t/hm2秸杆处理其N2O的排放量仅为对照或施用2.25t/hm2秸杆处理下的13%左右.综合考虑水稻生长季CH4和N2O排放的全球增温潜势(GWP),在增加有机质的施用量(如按4.5t/hm2施用量秸杆还田)的情况下,烤田的GWP只占连续淹水处理的60%,是减少稻田CH4和N2O综合温室效应的一种有效措施.

Influence of water controlling and straw application on CH4 and N2O emissions from rice field

In June to October of the year 2000, a field experiment was carried out in the county of Jiangning near NanjingMainly, the influence of different application (0, 2.25, 4.5t/hm2) of organic matter (wheat straw) on CH4 and N2O emissions from rice field was studied under the conditions of conventional irrigation and permanent flooding inrice-growing season. Under permanent flooding condition CH4 emissions were positively related to straw application, and N2O emissions were negatively related to straw application. Under the application of 2.25t/hm2, N2O emissions from the plots with drainage events were not different significantly from the control; but under the application of 4.5t/hm2, it was only about 13% of the control or that with 2.25t/hm2 straw application. Considering integratedly the total global warming potential (GWP) of CH4 and N2O emissions in rice-growing season, under the condition of increasing the organic matter application (such as that of 4.5t/hm2) the GWP of drainage was only 60% of that of permanent flooding; thus, it was an effective strategy for mitigation of CH4 and N2O greenhouse effect of rice field.