烤田对种稻土壤甲烷排放的影响

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台田后前１６和４２小时内有大量甲烷排放，且在烤田后不久土壤呈微干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点水稻生长期甲烷排放总量的５．９６％～１０．０５％。

EFFECT OF SOIL DRYING ON CH4 FLUX FROM RICE PADDY SOIL

A pot experiment in greenhouse was carried out to study the effect of soil drying on CH₄ 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 dying 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 5.960%-10.05% of the total seasonal emissions.Although soil drying increased CH₄ exmssions by 9.68%-145.94% during soil drying,CH₄ emissions from the soils once imposed by soil drying decreased by 21.59%-54.45% during the period flooded after soil drying,compared with that from the soils flooded continuously.Considering overall CH₄ emissions during soil drying and the period flooded again,soil drying reduced CH₄ emissions by 17.7-43.91 percent.