耕作方式对山地烟田烤烟根际土壤真菌群落结构的影响

  目的  探究深耕、深松措施对山地烟田土壤真菌群落结构的影响。  方法  采用大田试验, 设置常规旋耕20 cm（RT20, 对照）、深耕30 cm（DT30）、深松30 cm（ST30）和深松40 cm（ST40）4个处理, 利用Illumina MiSeq高通量测序技术分析了不同耕作处理下旺长期烤烟根际土壤真菌群落结构的变化情况。  结果  （1）与RT20相比, DT30、ST30和ST40处理中根际土壤真菌OTU丰度分别提升了9.19%、13.11%和6.32%, 其中DT30、ST30处理所特有的OTUs数分别是RT20的1.30倍和1.18倍; （2）不同深耕和深松处理后根际土壤真菌群落丰富度和多样性均有所增加, 其中DT30、ST30和ST40处理的Shannon指数与对照相比分别提升了8.23%、7.46%和4.63%, Chao1指数分别提升了8.27%、13.39%和4.26%;（3）在门、属和种水平上不同耕作处理优势菌群及相对丰度均有显著差异, 与RT20相比, DT30、ST30和ST40处理中镰刀菌属（Fusarium）真菌相对丰度分别降低了25.34%、14.53%和18.41%, 茎点霉属（Phoma）相对丰度分别降低34.96%、31.17%和33.33%;另外, 青霉属（Penicillium）和紫霉属（Purpureocillium）等有益真菌相对丰度较RT20均表现出增加趋势。  结论  深耕和深松措施促进了微生物群落结构的重建, 有利于提升烤烟根际土壤真菌群落多样性, 并在一定程度降低潜在土传病原真菌的相对丰度, 促进有益土壤微生物生长, 从而对山地烟田烤烟根际土壤微环境有一定改善作用。 

Effects of tillage methods on fungal community structure in rhizosphere soil of flue-cured tobacco in mountainous tobacco fields

  Objective  To explore the effects of deep tillage and subsoiling tillage on the soil fungal community structure of mountainous tobacco fields,  Methods  The field experiment was conducted in four treatments: 20cm of rotary tillage (control, RT20), 30 cm of deep tillage (DT30), 30 cm (ST30) and 40 cm (ST40) of subsoiling tillage. The changes of fungal community structure in the rhizosphere soil of flue-cured tobacco under different tillage treatments were discussed by Illumina MiSeq high-throughput sequencing technology analysis.  Results  (1) Compared with the control (RT20), the OTU richness of fungi in the rhizosphere soil samples of DT30、ST30 and ST40 increased by 9.19%, 13.11% and 6.32%, respectively; the number of OTUs peculiar to DT30 and ST30 were 1.30 times and 1.18 times that of RT20, respectively. (2) The richness and diversity of fungi community in rhizosphere soil increased after different deep tillage and subsoiling treatments. Compared with RT20, the Shannon index of DT30, ST30 and ST40 increased by 8.23%, 7.46% and 4.63% respectively, and the Chao1 index increased by 8.27%, 13.39% and 4.26%, respectively. (3) At the phylum, genus and species levels, the dominant bacterial communities and relative abundance of the bacterial communities under different tillage treatments were significantly different. Compared with RT20, the relative abundance of Fusarium in DT30, ST30 and ST40 treatments decreased by 25.34%, 14.53% and 18.41%, respectively; the relative abundance of Phoma decreased by 34.96%, 31.17% and 33.33%, respectively; what's more, the relative abundance of beneficial fungi such as Penicillium and Purpureocillium in deep tillage and subsoiling tillage showed an increasing trend compared with RT20.  Conclusion  Deep tillage and subsoiling tillage can promote the reconstruction of the microbial community structure, which is beneficial to increase the diversity and richness of fungal communities in flue-cured tobacco rhizosphere soil, and reduced the relative abundance of soil-borne pathogenic fungi to a certain extent, thus improving the microenvironment of tobacco rhizosphere soil in mountainous tobacco fields.