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冬季的温室气体排放往往被忽视,而最新的研究结果表明,冬闲稻田和冬季油菜地N_2O排放仍较大,研究相应的减排措施及减排机制对于减少农田土壤N_2O排放有重要意义.在中国科学院桃源农业生态试验站选择冬闲稻田和油菜地两种不同土地利用方式,并设置添加和不添加双氰胺(DCD)处理,采用静态箱采集和气相色谱法结合监测N_2O排放动态,利用分子生物学手段分析氨氧化古菌(AOA)和氨氧化细菌(AOB)的群落结构和丰度变化.结果表明,添加DCD后明显抑制了冬闲稻田和油菜地N_2O排放,分别减少了36.7%和23.6%.DCD施入抑制了冬闲稻田AOA和AOB的丰度但只改变AOA的群落结构,DCD使AOA和AOB丰度分别减少了59.3%和73.7%.与此相反,添加DCD只改变油菜地AOB的群落结构同时只抑制了AOB的丰度.本研究表明,施加DCD能有效减少冬闲稻田和冬季油菜地N_2O排放,但减排机制不一致.
The greenhouse gas emissions in winter are often neglected, and the latest research results show that N 2 O emissions in winter and winter rapeseed fields are still relatively large, and studying corresponding emission reduction measures and emission reduction mechanisms is of great significance to reduce N 2 O emissions from agricultural soils. Taoyuan Agro-Ecological Experimental Station of Academy of Sciences selected two types of land use patterns of winter paddy rice and rapeseed land, with or without dicyandiamide (DCD) treatment, static box detection and gas chromatography combined with monitoring of N 2 O emission dynamics, (AOA) and ammonia-oxidizing bacteria (AOB) were analyzed by means of the laboratory.The results showed that the N 2 O emission of winter paddy and rapeseed obviously decreased by 36.7% and 23.6%, respectively, .DCD application suppressed the abundance of AOA and AOB in winter and paddy fields but only changed the community structure of AOA, DCD reduced the AOA and AOB abundance by 59.3% and 73.7% respectively. On the contrary, adding DCD only changed the AOB At the same time, the community structure only suppresses the abundance of AOB.The present study shows that the application of DCD can effectively reduce N 2 O emissions in winter and winter rapeseed, but the emission reduction mechanism is not consistent.