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透气性良好的旱田土壤是大气CH4的主要吸收汇,对于降低大气CH4浓度具有非常重要的意义.本研究在三江平原选择两块旱田,分别于1987年和1993年由沼泽湿地开垦而成(分别简写为87D和93D),种植方式均为大豆-冬闲,利用静态暗箱/气相色谱法对2003年和2004年两个生长季的CH4排放进行了野外观测,发现不同垦殖年限的两块旱田在CH4氧化速率上没有明显差异,但它们均具有显著的年际变化特征,2003年大豆生长季内87D旱田表现为向大气排放CH4,排放量为0.68 kg/hm2,而2004年则表现为吸收大气CH4,吸收量为1.29 kg/hm2;93D旱田在2003年和2004年大豆生长季内均表现为吸收大气CH4,吸收量分别为0.57和1.07 kg/hm2,旱田CH4排放上的这种年际变化主要是由大气降水的年际差异造成的.土壤水分状况是控制CH4氧化速率的主要因素,二者呈负相关关系.植物参与能够显著提高土壤氧化CH4的能力,2004年,在植物的参与下,93D旱田和87D旱田土壤与无植物处理相比对CH4的氧化能力分别提高了197.2%和268.6%.
Well-ventilated dry soil is the major sink of atmospheric CH4, which is of great significance for reducing CH4 concentration in the air.In this study, two dry fields were selected in the Sanjiang Plain, reclaimed from marsh wetlands in 1987 and 1993 Abbreviated as 87D and 93D). All the cultivation methods were soybean-winter-free. The static dark box / gas chromatography was used to observe the CH4 emission in two growing seasons in 2003 and 2004. There was no significant difference in the oxidation rate between them, but both of them had significant interannual variation. In the 2003 soybean growing season, 87D dryland showed CH4 emissions to the atmosphere at 0.68 kg / hm2, while in 2004 it was shown to absorb CH4 , And the uptake was 1.29 kg / hm2. In the 2003D and 2003 soybean growing seasons, the uptake of CH4 was 0.57 and 1.07 kg / hm2, respectively. This annual variation of CH4 emissions in upland fields was mainly Is caused by the interannual difference of precipitation.The soil water status is the main factor to control the oxidation rate of CH4 and there is a negative correlation between the two.Plant participation can significantly improve the ability of the soil to oxidize CH4.In 2004, Under participation, 93D and 87D dry upland soils compared with no treatment plant for oxidation of CH4 increased by 197.2% and 268.6%.