水稻品种间作对甲烷排放的影响

Impact of intercropping of rice cultivars on methane emissions

作物品种多样化种植是提高农业生态系统功能的有效措施,但不同品种混合种植能否影响温室气体排放仍然缺乏研究。本研究以水稻为例,通过原位盆栽试验,研究品种间隔种植(间作)对甲烷排放的影响。以甲烷高排放品种常农粳8号、皖稻153以及甲烷低排放品种苏香粳100、Ⅱ优084为供试材料,设置8个处理,包括4个水稻品种单一种植(单作),即常农粳8号单作(记作CN)、皖稻153单作(WD)、苏香粳100单作(SX)、Ⅱ优084单作(ⅡY),以及2个甲烷高排放品种与2个甲烷低排放品种间作,即常农粳8号+Ⅱ优084间作(CN+ⅡY)、常农粳8号+苏香粳100间作(CN+SX)、皖稻153+Ⅱ优084间作(WD+ⅡY)、皖稻153+苏香粳100间作(WD+SX)。间作品种按1∶1的株数比例间隔种植。结果表明,4个间作处理均能显著增加或维持水稻产量。不同间作处理的甲烷排放通量存在显著差异,与期望值相比,CN+SX处理显著降低甲烷的排放,而CN+ⅡY、WD+ⅡY处理则显著增加甲烷排放。与甲烷高排放品种的单作处理相比,苏香粳100与2个甲烷高排放品种间作时均能显著降低生长季土壤产甲烷古菌mcrA基因平均丰度,但Ⅱ优084仅在与皖稻153间作时有显著作用。除CN+SX外,其余3个间作处理下生长季土壤甲烷氧化菌pmoA基因平均丰度均显著低于所对应的单作处理。本研究认为可以通过水稻品种间作在获得增产的同时降低甲烷排放,但品种间作组合需要仔细筛选。

Diversified farming of crop cultivars is an effective measure for improving agroecosystem functions.However,there is still a lack of research on the effects of mixed planting of different cultivars on greenhouse gas(GHG)emissions.In this study,rice was used as an example to explore the impact of intercropping of different cultivars on methane(CH4)emissions through an in situ pot experiment.The cultivars Changnongjing No.8 and Wandao No.153,which have high CH4 emissions,and the cultivars Suxiangjing No.100 andⅡ-you No.084,which have low CH4 emissions,were selected as experimental materials.A total of eight treatments were set up in this study.The monocultures of four cultivars were as follows:the monoculture of Changnongjing No.8(referred to as CN),the monoculture of Wandao No.153(WD),the monoculture of Suxiangjing No.100(SX)and the monoculture ofⅡ‒you No.084(ⅡY).Additionally,intercropping systems were set up between two CH4 high-emission cultivars and two CH4 low-emission cultivars:intercropping of Changnongjing No.8 and Suxiangjing No.100(CN+SX),intercropping of Changnongjing No.8 andⅡ‒you No.084(CN+ⅡY),intercropping of Wandao No.153 and Suxiangjing No.100(WD+SX),and intercropping of Wandao No.153 andⅡ‒you No.084(WD+ⅡY).In the intercropping treatments,the two cultivars were planted at a ratio of 1∶1.The results showed that all the intercropping treatments either significantly increased or maintained rice yield,and that the CH4 emissions varied significantly among the different intercropping treatments.Compared with the expected values,the CN+SX treatment resulted in a significant reduction in CH4 emissions,while the CN+ⅡY and WD+ⅡY treatments significantly increased the CH4 emissions.Compared with the monoculture of CH4 high emission cultivars,the intercropping of Suxiangjing No.100 with two CH4 high-emission cultivars significantly reduced the average abundance of the methanogenic archaeal mcrA gene during the growing season,butⅡ‒you No.084 had a significant effect only when intercropped with Wandao No.153.For the intercropping treatments except CN+SX,the average abundance of the methanotrophic bacterial pmoA gene during the growing season was significantly lower than that of the corresponding monoculture.This study suggested that the intercropping of rice cultivars can enhance rice yield and also reduce CH4 emissions,but the appropriate combinations of intercropped cultivars should be selected carefully.