黔西北地区稻-油轮作系统土壤肥力及细菌群落特征对连续施用新型肥料的响应OA

[Objective]The effects of continuous applying different new fertilizers on soil fertility and bacterial community structure of yellow paddy soil under the water-drought rotation mode(rice-rape rotation)to provide a theoretical basis for scientific application and healthy soil cultivation of new fertilizers under the rice-rape rotation system in Northwest Region of Guizhou.[Method]The effects of four fertilization treatments[conventional fertilizer(F),organic-inorganic compound fertilizer(OF),biochar-based fertilizer(BF)and stable slow-release fertilizer(WF)]on soil physicochemical properties and bacterial community structure under a continuous water-drought rotation system were investigated by using Illumina NovaSep high-throughput sequencing technology,and the key factors influencing soil bacterial community changes were explained by the Mantel test,hierarchical clustering and redundancy analysis.[Result]Applying new fertilizers could effectively promote soil fertility,and the soil fertility in rape season was higher than that in rice season overall.The soil pH and organic matter content of OF,BF and WF treatments increased by 2.39%-3.08%and 20.96%-32.12%in rape season compared with those of F treatment,respectively.There was an obvious season difference in soil NO3-N content.The soil NO3-N content was 6.36-7.07 mg/kg in rice season and reached 33.77-38.33 mg/kg in rape season.One-time applying new fertilizer influenced the diversity of soil bacterial community structure significantly and there was a difference in relative abundance of soil bacterial community structure diversity.The Pielou index of OF treatment was significantly higher than that of F treatment.The Shannon and Pielou indexes of BF and WF treatments both were higher than those of F treatment.A total of 42 bacterial communities at phylum level were detected.The relative abundance of Proteobacteria and Actinobacteriota of OF and WF treatments increased by 7.5%and 13.1%,and 15.2%and 16.8%compared with F treatment,respectively.The relative abundance of Chloroflexi and Myxococcota of BF treatment increased by 19.3%and 17.4%compared with F treatment,separately.A total of 366 bacterial communities at genus level were detected.The relative abundance of Rokubacteriales of OF,BF and WF treatments was 36.16%-48.37%higher than F treatment.The results from Mantel test,hierarchical clustering and redundancy analysis showed that the similarity in bacterial community composition among F,OF and WF treatments was relatively higher,but there was a significant difference in bacterial community composition between BF treatment and above-mentioned three treatments.The soil physicochemical factors influenced diversity of soil bacterial communities significantly.Increasing soil pH,organic matter and available phosphorus could promote diversity of soil bacterial communities synergistically.The available phosphorus,organic matter and pH were the key factors influencing soil bacterial community structure,and the available phosphorus was the dominant factor influencing soil bacterial community composition.[Conclusion]Applying new fertilizers can effectively improve soil fertility,optimize the environmental conditions for bacterial growth,and promote stable and healthy sustainable development of farmland soil ecosystem under the rice-rape rotation system in Northwest Region of Guizhou.