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      不同连作年限烟田的土壤线虫群落结构特征

      Characteristics of Soil Nematode Community Structure in Tobacco Fields with Different Continuous Cropping Years

      • 摘要: 为解析烟草连作年限与土壤线虫群落特征的关系,本研究采集了鄂西烟区35个烟草田块,分别属于连作2年、5-10年、11-20年、21-30年以及>30年等5个年限类型,采用高通量测序方法,研究了不同连作年限烟田对土壤线虫群落结构及营养类群的影响。结果表明:烟田连作年限增加提升了土壤线虫多样性,改变了线虫群落结构。在鉴定的36个线虫属中,11个线虫属在不同连作年限间存在显著差异,其中隐杆线虫属Caenorhabditis的相对丰度在连作10年后增加,真滑刃属Aphelenchus、单齿属Mononchus、盆咽属Panagrolaimus的变化则相反。随连作年限增加,线虫成熟度指数先升高后降低,食细菌线虫的相对丰度先降后增,而食真菌线虫相对丰度显著下降,富集指数和结构指数在长期连作(高于10年)中较高。进一步的区系分析发现短期连作(低于10年)和长期连作(高于10年)烟田的线虫群落明显分离。综合分析得出,长期连作(高于10年)会增加土壤线虫群落多样性和改变营养类群结构,土壤养分富集且受干扰程度低,同时揭示了土壤微环境从初始胁迫到长期稳定的动态过程。

         

        Abstract: To clarify the relationship between tobacco continuous cropping duration and soil nematode community characteristics, 35 tobacco fields were sampled in the western Hubei tobacco-growing region, which were categorized into five continuous cropping duration groups: 2 years, 5-10 years, 11-20 years, 21-30 years, and >30 years. High-throughput sequencing was employed to investigate the effects of different continuous cropping durations on soil nematode community structure and trophic groups. The results showed that the increase in tobacco field continuous cropping duration enhanced soil nematode diversity and altered the nematode community structure. Among the 36 identified nematode genera, 11 showed significant differences among different continuous cropping durations. Specifically, the relative abundance of Caenorhabditis increased after 10 years of continuous cropping, while the opposite trend was observed for Aphelenchus, Mononchus and Panagrolaimus .With the extension of continuous cropping duration, the nematode maturity index first increased and then decreased; the relative abundance of bacterivorous nematodes (bacterivores) first decreased and then increased, while that of fungivorous nematodes (fungivores) significantly declined. Both the enrichment index and structural index were higher under long-term continuous cropping (over 10 years). Further nematode faunal analysis indicated that the nematode communities in short-term continuous cropping (under 10 years) and long-term continuous cropping (over 10 years) were significantly separated. Comprehensive analysis revealed that long-term continuous cropping (over 10 years) increases soil nematode community diversity, alters the structure of trophic groups, enriches soil nutrients, and reduces environmental disturbance intensity. Additionally, this study elucidates the dynamic process of the soil microhabitat from initial environmental stress to long-term stability.

         

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