Abstract: In order to study the effects of different straw returning methods on soil environmental factors and bacterial community structure under rice‑wheat rotation system, three treatments were set up as follows: straw removal + traditional rotary tillage (RTNSR), straw returning + traditional rotary tillage (RTSR), straw returning + vertical deep rotary tillage (VTSR). The changes of soil organic carbon components and microbial community structure under different tillage modes were studied, and the molecular ecological network and ecological module of bacterial community were constructed to explore the correlation between soil organic carbon components and bacterial community and network characteristics. The results showed that compared with treatment RTNSR, soil alkali‑hydrolyzable nitrogen content was significantly increased in both treatment RTSR and VTSR, which were 93.71 mg/kg and 96.47 mg/kg, respectively, and soil available phosphorus content was increased by about 3.42% and 21.20%, respectively, the soil microbial biomass carbon and nitrogen contents in treatment VTSR were 211.76 mg/kg and 29.37 mg/kg, respectively, which were significantly increased by about 17.95%, 55.72%, the soil microbial biomass carbon was significantly increased by about 27.51% and microbial biomass nitrogen content was 27.69 mg/kg in treatment RTSR, which was significantly increased by 46.81%, soil total organic carbon, organic carbon mineralization, and heavy organic carbon contents in treatment VTSR increased by about 1.32%, 17.45% and 10.18% as well. Proteobacteria, Acidobacteriota and Gemmatimonadota were the main dominant phyla of soil bacterial community. Acidobacteriota, Chloroflexi, Proteobacteria and Gemmatimonadota as the module key species phylum were found in the soil bacterial community co‑occurrence network, and environmental factors such as pH, total phosphorus, total potassium, and particulate organic carbon significantly drove the changes of these keystone species in the community. In summary, straw returning+vertically rotary sub‑soiling tillage could regulate the soil fertility level, change the contents of soil organic carbon components, and influence the interactions between soil bacterial communities.

Key words: straw returning, vertically rotary sub?soiling tillage, soil nutrients, bacterial community, microbial co?occurrence network

摘要： 为研究稻麦轮作体系下不同秸秆还田方式对土壤环境因子和细菌群落结构的影响，设置秸秆移除+传统旋耕(RTNSR)、秸秆还田+传统旋耕(RTSR)、秸秆还田+立式深旋耕作模式(VTSR)3种处理，研究不同耕作模式下土壤有机碳组分、微生物群落结构变化，并构建细菌群落分子生态网络和生态模块，探讨土壤有机碳组分与细菌群落、网络特征之间的关联。结果表明：与处理RTNSR相比，处理RTSR和VTSR中土壤碱解氮含量均明显提高，分别为93.71 mg/kg、96.47 mg/kg；土壤速效磷含量分别提高约3.42%、21.20%；处理VTSR中土壤微生物量碳、氮含量分别为211.76 mg/kg、29.37 mg/kg，显著提高约17.95%、55.72%；且处理RTSR中土壤微生物量碳显著提高约27.51%、微生物量氮含量为27.69 mg/kg，显著提高46.81%；处理VTSR中土壤总有机碳、可矿化有机碳以及重组有机碳含量也提高约1.32%、17.45%和10.18%。变形菌门、酸杆菌门、芽单胞菌门是土壤细菌群落的主要优势菌门。土壤细菌群落共现网络中发现，酸杆菌门、绿弯菌门、变形菌门和芽单胞菌门均为模块关键物种菌门，pH值、总磷、总钾、颗粒有机碳等环境因子对这些关键物种在群落中的变化具有明显的驱动作用。秸秆还田+立式深旋耕作可以调节土壤肥力水平、改变土壤有机碳各组分含量，并影响土壤细菌群落间的互作关系。

关键词: 秸秆还田, 立式深旋耕作, 土壤养分, 细菌群落, 微生物共现网络