间隙灌溉和控释肥施用耦合措施对稻麦轮作系统土壤微生物群落丰度的影响

Effect of the Coupling Technique of Intermittent irrigation and Controlledrelease Fertilizer on the Abundance of Soil Microbial Communities from Rice-wheat Rotation Ecosystem

间隙灌溉模式下控释肥施用可减缓稻麦轮作系统CH_4和N_2O排放交互排放效应,从而降低综合温室效应,然而有关间隙灌溉和控释肥施用耦合措施对稻麦轮作系统土壤微生物的影响鲜有研究。通过采集稻麦轮作系统田间原位试验新鲜土样,采用核酸定量技术研究间隙灌溉和控释肥施用耦合措施下稻麦轮作系统土壤微生物群落丰度的变化,以探讨此耦合措施降低稻麦轮作系统降低CH_4和N_2O排放的微生物机理。结果发现,除古菌外,稻季土壤细菌、产甲烷菌、甲烷氧化菌、氨氧化菌和反硝化菌群落丰度均高于麦季;间隙灌溉显著影响稻田产甲烷菌、甲烷氧化菌、氨氧化菌和反硝化菌数量的季节变化;与尿素相比,施用控释肥增加了稻麦轮作系统细菌、古菌和产甲烷菌数量,降低了甲烷氧化菌、氨氧化菌、反硝化菌数量。稻季CH_4和N_2O的排放量与土壤微生物丰度之间存在显著相关性:CH_4排放量与古菌、产甲烷菌和甲烷氧化菌数量均呈极显著正相关关系(P<0.01),而与氨氧化菌数量呈显著负相关关系(P<0.05);N_2O排放量与氨氧化菌、甲烷氧化菌、nirK型和nosZ型反硝化菌数量均呈显著正相关关系(P<0.05),而与nir S型反硝化菌无显著相关性。研究表明,间隙灌溉和控释肥施用耦合措施通过影响稻麦轮作系统相关功能微生物的群落丰度进而减缓CH_4和N_2O气体的交互排放效应。

The coupling technique of intermittent irrigation and controlled-release fertilizer （CRF） application is expected to reduce CH4 and N2O emissions from rice-wheat rotation ecosystem by the author’s previous studies, but its effect on the microbial communities remain poorly understood. Fresh soils were sampled through the rice-wheat rotation seasons in a field experiment to elucidate the microbial mechanisms of effects of the coupling technique of intermittent irrigation and controlled-release fertilizer （CRF） application on CH4 and N2O emissions by analyzing the abundance of soil microbial communities using the method Real-time PCR. The abundances of bacterial, methanogens, methanotrophs, ammonia-oxidizing bacteria and denitrifiers were higher during rice growing season than that during wheat growing season. Intermittent irrigation significantly influenced the seasonal variation of abundances of methanogens, methanotrophs, ammonia-oxidizing bacteria and nirS/nirK/nosZ-type denitrifiers. Compared with urea, CRF increased the abundances of archaea, bacteria and methanogens, while decreased the abundances of methanotrophs, ammonia-oxidizing bacteria, nirS/nirK/nosZ-type denitrifiers. CH4 and N2O emissions were significantly correlated with the abundances of soil microbial communities. CH4 emission was positively correlated with the abundances of archaea, methanogens and methanotrophs （P〈0.01）, while it was negatively correlated with the abundances of ammonia-oxidizing bacteria （P〈0.05）. N2O emission was positively correlated with the abundances of ammonia-oxidizing bacteria, methanotrophs, nirK-type and nosZ-type denitrifiers （P〈0.05）, while no significant relationship was found with nirS-type denitrifiers. The results indicated that the couplingtechnique of intermittent irrigation and controlled-release fertilizer application mitigated the CH4 and N2O emissions from rice-wheat rotation ecosystem by influencing the abundance of related functional microbial communities.