豌豆绿肥翻压入土对攀枝花地区连续多年植烟土壤细菌多样性的影响

Application of pea green manure alters bacterial diversity in the soil cultivated with tobacco for years in Panzhihua

摘要:

【背景】攀枝花植烟地区的连作现象及不良施肥习惯给植烟土壤的养分平衡和微生物群落多样性带来了严重的胁迫，这导致了烟叶产量和品质的下滑，对烟草行业的健康和持续发展造成了严重威胁。【目的】研究豆科绿肥接种根瘤菌并翻压入土对攀枝花烟区新垦烟地和多年连续植烟地土壤细菌多样性和组成的影响，以期为科学施肥提供可靠的理论依据，为攀枝花烟区建立合理的烤烟种植模式。【方法】以攀枝花米易县坪山乡新垦烟地和多年连续植烟地为研究对象，收集了豌豆绿肥混入土壤的样本，对其土壤的物理和化学性质进行了测定，并利用高通量测序技术对细菌群落的组成和多样性进行了深入分析。【结果】接种根瘤菌能够有效提高豌豆苗期的结瘤数和根数，尤以在新垦烟地上的施用效果最佳。使用绿肥进行翻压可以增加烟草种植土壤中的有机碳和无机营养成分，同时也能降低土壤的pH值和容重。豌豆绿肥的翻压显著地影响了种植烟草的土壤中细菌的多样性和构成。绿肥翻压提高了新垦烟地的土壤细菌Simpson和Shannon多样性指数而降低了连作烟地上相关多样性的指标。不同植烟年限土壤的优势菌群包括变形菌门(Proteobacteria)、绿弯菌门(Chloroflexi)及放线菌门(Actinobacteria)，而不同植烟年限土壤的优势菌属是不动杆菌属(Acinetobacter)、苍白杆菌属(Ochrobactrum)、鞘脂单胞菌属(Sphingomonas)和链霉菌属(Streptomyces)。通过冗余分析发现土壤的pH值、速效钾(available potassium, AK)及碱解氮(alkali-hydrolyzed nitrogen, AN)与微生物群落结构之间的相关性是最显著的(P<0.05)。【结论】豌豆绿肥翻压入土能提高植烟土壤养分条件，改变不同植烟土壤细菌多样性和细菌群落组成。

Abstract:

[Background] The continuous cropping and poor fertilization habits in the tobacco-planting areas of Panzhihua have brought serious stress to the nutrient balance and microbial diversity in the soil, leading to declines in the yield and quality of tobacco and seriously affecting the development of the tobacco industry. [Objective] To study the effects of applying rhizobium-inoculated leguminous green manure on the microbial diversity and community composition in the soil cultivated with tobacco for years in Panzhihua and provide a theoretical basis for scientific fertilization and establishment of a reasonable planting pattern of flue-cured tobacco in Panzhihua. [Methods] We collected soil samples from the newly reclaimed tobacco field and the field planted with tobacco for years (both with the application of green manure) in Pingshan Township, Miyi County of Panzhihua. The physical and chemical properties of the soil samples were determined, and the bacterial community composition and diversity were analyzed by high-throughput sequencing. [Results] Inoculation with rhizobia increased the number of nodules and roots of pea seedlings, especially in the newly reclaimed tobacco field. The application of green manure increased the content of organic carbon and inorganic nutrients in soil and reduced soil pH and volume weight. In addition, the application of pea green manure changed the bacterial diversity and community composition in the soil. Specifically, it elevated the Simpson and Shannon indexes of bacteria in the newly reclaimed tobacco field and reduced the relevant diversity indexes in the field cultivated with tobacco for years. The predominant bacterial phyla of the soil samples planted with tobacco for different years included Proteobacteria, Chloroflexi, and Actinobacteria, while the dominant bacterial genera were Acinetobacter, Ochrobactrum, Sphingomonas, and Streptomyces. The redundant analysis showed that soil pH, available potassium (AK), and alkali-hydrolyzed nitrogen (AN) had strong correlations with the microbial community structure (P<0.05). [Conclusion] The application of green manure improves the nutrients and changes the bacterial diversity and community composition of the tobacco-growing soil.