种植杂交稻对甲烷排放的影响及评价

早、中、晚稻三季24h稻田甲烷监测结果表明，种植杂交稻没有明显增进福田甲烷排放的作用．甲烷释放总量在3个种植季节中，除连作晚稻的杂交稻田比常规稻田高11．6％外，早稻、单季稻杂交稻田分别低于常规稻田6．4％和8．9％．稻田甲烷每周日平均释放量在水稻生长前期（移栽后5～7周）杂交稻高于常规稻，孕穗至收获期杂交稻低于常规稻．温度对甲烷释放影响十分明显．在不同水稻种植季节，稻田甲烷释放模式各不相同．经测定，杂交稻田的土壤产甲烷细菌数量及土壤产甲烷潜力明显高于常规稻田，其中产甲烷细菌数可相差数倍至2个数量级．试验结果还表明，种植水稻明显增加了稻田甲烷排放量，与侵水稻田相比．植稻田甲烷排放量增加了41．4％．

Evaluation of the effect of planted hybrid rice on methane emission from paddy field

The experiments of planted hybrid and conventional rice in double and single season were carried out in 1996. The integrating continuous CH4 flux measurements showed that CH4 emission from hybrid rice field was higher in the early growth stage (5~7 weeks after transplanting) and lower in late stage (booting-harvesting) than those from conventional rice in three planting seasons. Compared with planted conventional rice, planted hybrid rice resulted in CH4 emission reduction by 6.4% in early rice and 8.9 % in single rice, and increment by 11.6 % in double late rice. As methane emission was highly effected by temperature, in different rice planting season the patterns of methane emission were different. The amounts of methane-producing bacteria and methane production potential of the soil planted hybrid rice were much higher than those of planted conventional rice. The experiment also demonstrated that methane emission in the field with planted rice was 41.4 %higher than that of unplanted rice.