南方双季稻区不同复种方式对稻田综合温室效应的影响

Effects of Different Multiple Cropping Pattern on the Global Warming Potential in Southern Double Cropping Rice Fields

为明确南方双季稻区不同复种方式对稻田综合温室效应和温室气体排放强度的影响,试验设置油菜-一季中稻(R-MR)、冬季绿肥(紫云英)-早稻-晚稻(GM-ER-LR)、冬闲-早稻-晚稻(WF-ER-LR)3个处理,采用静态暗箱-气相色谱法监测周年温室气体排放,探明不同复种方式对周年作物产量、稻田全球增温潜势(GWP)、籽粒能量产出(GEY)和全球增温潜势强度(GWPI)的影响。结果表明,与R-MR相比,GM-ER-LR和WF-ER-LR显著增加了CH4累积排放量(分别提高1.27倍和1.18倍),显著降低了N2O累积排放总量(分别降低34.1%和49.4%),GM-ER-LR和WF-ER-LR的CH4和N2O累积排放量无显著差异。与R-MR相比,GM-ER-LR和WF-ER-LR显著提高了周年GEY(分别提高28.6%和27.0%)。在100年时间尺度上,GM-ER-LR和WF-ER-LR的稻田GWP分别是R-MR的1.27倍和1.18倍,GWPI分别较R-MR提高100%和50%。因此,GM-ER-LR和WF-ER-LR有利于提高作物产量,但会增加稻田综合温室效应和温室气体排放强度。鉴于双季稻区中稻面积有增大的趋势,综合环境效益和经济效益,油菜-一季中稻减排增效效果更好。

To examine effect of different multiple cropping pattern on the global warming potential and greenhouse gas intensity in the double cropping rice fields,the experiment was set up to rapeseed-middle rice rotation(R-MR),green manure(milk vetch)-early rice-late rice rotation(GM-ER-LR),and winter fallow-early rice-late rice rotation(WF-ER-LR).The different cropping patterns for annual crop yield rice field global warming potential(GWP),grain energy yield(GEY)and global warming potential(GWPI)were identified by the static opaque chamber-gas chromatography method.The results showed that compared to R-MR,the CH4 emissions of GM-ER-LR and WF-ER-LR significantly increased by 1.27 and 1.18 times,respectively,whereas N2O emissions were significantly reduced by 34.1%and 49.4%,respectively.No significant differences were found in CH4 and N2O emissions between GM-ER-LR and WF-ER-LR.Compared with R-MR,the grain energy yield significantly increased by28.6%and 27.0%in GM-ER-LR and WF-ER-LR,respectively.The global warming potential was 1.27 and 1.18 folds higher in GM-ER-LR and WF-ER-LR than in R-MR.The global warming potential intensity increased by 100%in GM-ER-LR and 50%in WF-ER-LR than in R-MR.Therefore,GM-ER-LR and WF-ER-LR were beneficial to enhance crop yield,but increased the global warming potential and greenhouse gas intensity.Thus,this study suggested that the rapeseed-middle rice rotation system could not only reduce greenhouse gas emissions but achieve higher environmental and economic benefits.