秸秆与水分管理稻田的温室气体排放和碳固定

Greenhouse Gases Emissions and Carbon Sequestration by Soils in Rice Paddy Fields as Affected by Rice Straw Incorporation and Water Management

文章采用田间小区试验,研究了不同秸秆(稻草)还田量和不同水分管理方式对稻田温室气体排放及土壤有机碳固定的影响。结果表明:无秸秆还田时,长期淹水增加温室效应的抵消作用大于间歇灌溉温室效应的抵消作用;高量秸秆还田时,长期淹水增加温室效应的抵消作用显著大于间歇灌溉温室效应的抵消作用;秸秆还田显著提高了甲烷(CH_(4))排放,减少了氧化亚氮(N_(2)O)排放,显著提高了土壤有机碳含量,有效提高了土壤固碳量,但温室气体增排的效应非常明显。高量秸秆还田时增加温室效应的抵消作用大于低量秸秆还田,其温室气体净排放更高。该研究中以间歇灌溉且低量秸秆还田处理为最佳处理,3.0 t/hm^(2)低量秸秆还田量和间歇灌溉可有效发挥稻田秸秆还田的环境效益。

Influence of different quantity of straw(rice straw) incorporation and different irrigation ways on greenhouse gas emissions and rice paddy soil organic carbon sequestration by field plot experiment was studied. The results showed that without rice straw incorporation, the offsetting effect of conventional irrigation treatment to increased greenhouse gas emissions was higher than that of intermittent irrigation treatment. With high levels of straw incorporation, the offsetting effect of conventional irrigation treatment to increased greenhouse gas emissions was significantly higher than that of intermittent irrigation treatment. Straw incorporation significantly increased methane(CH_(4)) emission, significantly decreased nitrous oxide(N_(2)O)emission, significantly increased soil organic carbon content and increased soil carbon sequestration. However, greenhouse effect of increased greenhouse gas emissions was very evident. The offsetting effect of plentiful straw incorporation to increased greenhouse gas emissions was higher than that of low levels of straw incorporation. The net greenhouse gas emission of high levels of straw-incorporation was higher than that of low levels of straw incorporation. The study indicated that intermittent irrigation and low levels of straw incorporation was the best treatment. Hence, it would bring good environmental benefits through straw incorporation when amount of straw incorporation was 3.0 t/hm^(2), as well as irrigation way was intermittent.