烤田对种稻土壤甲烷排放的影响

EFFECT OF SOIL DRYING ON CH_4 FLUX FROM RICE PADDY SOIL

本文通过温室盆栽试验研究了烤田对种稻土壤甲烷排放的影响。在水稻移栽后的第４３天和１０２天各烤田一次，持续时间分别为２８和１１３小时。结果表明种稻土壤在开始烤田后前 １６和 ４２小时内有大量甲烷排放，且在烤田后不久土壤呈微于松软状态时出现甲烷排放高峰。随着烤田的延续，至土壤呈干裂状态时甲烷排放通量降为零。烤田能促进土壤闭蓄态甲烷的排放，烤田期间甲烷排放量占水稻生长期甲烷排放总量的５．９６％～１０．０５％。虽然烤田期间烤田使土壤甲烷排放量增加了９．６８％～１４５．９４％，但重新淹水后经历烤田土壤较持续淹水土壤甲烷排放量减少了２１．５９％～５４．４５％。综合考虑烤田及重新淹水期间甲烷排放量，烤田使种稻土壤甲烷排放量减少了１７．７０％～４３．９１％。

Summary A pot experiment in greenhouse was carried out to study the effect of soil drying on CH_4 flux from rice paddy soil. The soil drying practice was Performed two times from 43 and 102 days respectively after rice transplanting, and the soil drying periods were 28 and 113 hours respectively. The results showed that a large amount of methane emitted to the atmosphere during 16 and 42 hours after the soils fell dry, and an emission Peak occurred quickly after the soils fell dry when the soils was dry and soft. As soil drying continued, the soils began to crack and CH4 emissions decreased to nil. Soil drying accelerated the release of soil-entrapped methane. CH4 emissions during soil drying accounted for 5.96the 10.05% of the total seasonal emissions. Although soil drying increased CH4 emissions by 9.68%-145.94% during soil drying, CH. emissions from the soils once imposed by soil drying decreased by if.21.59%~54.45% during the Period flooded after soil drying, compared with that from the soils flooded continuously. Considering overall CH. emissions during soil drying and the Period flooded again, soil drying reduced CH4 emissions by 17.7--43.91 Per cent