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1、典型除草劑對稻麥輪作系統(tǒng)溫室氣體排放的影響顯著促進了生態(tài)系統(tǒng)呼吸速率,而后對生態(tài)系統(tǒng)呼吸速率沒有顯著影響。在第一次除草劑施入后丁草胺和芐嘧磺隆促進了CH4的排放,至第二次除草劑施入后,丁草胺和芐嘧磺隆抑制了cH4的排放。丁草胺顯著增加了N20的排放量(尸<0.05),是對照的1.77倍,芐嘧磺隆處理的N20的排放量與對照相比無顯著差異(尸>O.05)。目前的研究結(jié)果可以得出,丁草胺處理N20排放的增加是由于土壤NH4+.N和N03"-N含量增加,而芐嘧磺隆處理對N20的排放無顯著影響是由于土壤NH4+-N含量增加和土壤N03"-N含量降低的綜合作用的結(jié)果。在本試驗
2、中,旱直播稻整個水稻季的平均土壤充水孔隙度為68.6%,硝化過程為產(chǎn)生N20的主要過程,硝化細菌的數(shù)量在N20的產(chǎn)生和排放中扮演著重要角色。麥季試驗結(jié)果表明,盡管3種除草劑乙草胺、苯磺隆和精惡唑禾草靈施用下生態(tài)系統(tǒng)呼吸速率和N20的季節(jié)排放模式?jīng)]有顯著差異,但方差分析結(jié)果顯示,乙草胺、苯磺隆和精惡唑禾草靈在中期都顯著抑制了生態(tài)系統(tǒng)呼吸速率。乙草胺顯著抑制了N20的排放(P<0.05),僅為對照的68.5%,其余兩種除草劑處理對N20的排放沒有顯著影響(尸>0.05)。在獲得相同經(jīng)濟價值條件下,乙草胺處理的N20排放量最低。關(guān)鍵詞:除草劑;N20;呼吸速率;旱直播稻
3、田;麥田IIABSTRACTEFFECTSoFTYPICALHERBICIDESoNGREENHOUSEGASESEMISSIOMSFROMARICE.Ⅵ僵mATROTATIONSYSTEMInrecentyears,globalwarmingandorganicpollutionhavebeenpaidmuchattentionastwomostimportantenvironmentalproblems.Farmlandecosystemisanimportantsourceofgreenhousegasesemission.Herbicides,asanim
4、portantpartoffieldmanagements,inevitablyinfluencegreenhousegasesemissionfromsoilbyaffectingthecropandtheactivityandcommunityofsoilmicroorganism.Theobjectivesofthisresearchwere:1)toexaminetheeffectofdifferenttypicalherbicidesandfertilizersapplicationongreenhousegasesemissionfromrice—wi
5、nterwheatrotationsystem,andfurther2)toexplorethepossibleaffectedmechanismofN20emission,andhencetheresultwouldbehelpfultoexactlyestimateormitigatefarmlandgreenhousegasesandproperlyutilizeherbicides.Toapproachtheaboveobjectives,indoorsimulationincubaionexperimentandfieldexperimentinsitu
6、wereemployedinthisstudy.Laboratorysimulationexperimentwascardedouttostudytheeffectsof6typicaldrylandherbicides(atrazine,paraquat,glyphosate,tribenuron—methyl,acetochlorandfenoxaprop-P—ethyl)onsoilrespirationandN20emissionsfromsoiladded、析mnitrogenfertilizers(NH4)2804orureaunderthecondi
7、tionof30%(g/g)soilmoistureandtostudytheeffectsof2typicalfloodedherbicides(butachlorandbensulfuron—methyl)、析tllureaapplicationonsoilrespiration,CHaandN20emissionsfromsoilunder55%(g/g)simulatedsoilmoisture.nericefieldexperimentdealt、析mtheeffectsoftheherbicidesbutachlorandbensulfuron-met
8、hylon