长期秸秆掩埋配施氮肥对土壤细菌群落特征的影响

Effects of Long-term Straw Burying and Nitrogen Fertilizer Application on Soil Bacterial Community Characteristics

为揭示典型潮土微生物群落及其生态网络对秸秆还田的响应机制,选择长期小麦-玉米轮作下不同秸秆还田处理的试验地为对象,应用高通量测序和生态网络等方法,阐明秸秆掩埋配施不同氮肥后土壤细菌群落组成、细菌网络共存关系以及与土壤养分的关联。结果表明:(1)与秸秆移除且不施氮肥处理相比,秸秆还田配合常规施肥处理显著降低土壤pH,提高了土壤TN、SOC、AP、AK和NO^(-)_(3)N-含量(P<0.05)。秸秆掩埋配施氮肥有利于增加土壤养分含量。(2)不同秸秆还田方式和氮肥施用量处理的细菌Alpha多样性无显著差异,而细菌群落结构差异显著。pH、SOC和TN等因子驱动了细菌群落结构变异。酸杆菌门、变形菌门、拟杆菌门和绿弯菌门是潮土细菌群落的主要优势菌门。(3)共现网络分析得到4个主要的生态集群,均与土壤养分有显著相关性。模块1中物种丰度与SOC、TN、TP、NO^(-)_(3)N-、AP和AK呈极显著负相关(P<0.001),与pH呈极显著正相关(P<0.001);模块2和模块3中物种丰度与大部分养分含量呈正相关,与pH呈负相关。综上所述,秸秆还田配施氮肥可以通过调节细菌生态关系,从而调控土壤肥力。研究结果可为秸秆的资源化利用和土壤施肥管理提供科学依据。

【Objective】In order to reveal the response mechanism of microbial community and ecological network to straw returning process in typical fluvo-aquic soil,we experimented with different straw-returning treatments under long-term wheat-maize rotation.【Method】The high-throughput sequencing and ecological network methods were utilized to analyze the soil bacterial community composition,bacterial network co-occurrence and their relationships with soil nutrient concentrations.【Result】The results indicated that compared to straw removal and no nitrogen fertilizer treatment,straw returning with conventional fertilization treatments significantly reduced soil pH,while increasing the content of TN,SOC,AP,AK and NO^(-)_(3)-N-(P<0.05).The treatments of straw burying with nitrogen fertilizers were beneficial for increasing soil nutrient content.Moreover,no significant difference in bacterial alpha diversity was observed between different straw-returning methods and different amounts of nitrogen fertilizers,but a significant difference was observed in bacterial community structure.Factors such as pH,SOC,and TN drove variations in bacterial community structure.Also,Acidobacteriota,Proteobacteria,Bacteroidota and Chloroflexi were the dominant phyla in the fluvo-aquic soil.Furthermore,co-occurrence network analysis revealed four main ecological clusters that were significantly correlated with soil nutrients.The abundances of taxa in module 1 were found to be inversely correlated with SOC,TN,TP,NO^(-)_(3)-N-,AP and AK(P<0.001),and positively correlated with pH(P<0.001).Conversely,the abundances of taxa in module 2 and module 3 were significantly positively correlated with most nutrient content,and negatively related to pH.【Conclusion】Therefore,it can be concluded that straw burying combined with nitrogen fertilizers can improve soil nutrient by regulating ecological relationships of microorganisms.The findings of this study can provide a scientific basis for the efficient utilization of straw and the efficient management of soil fertilization.