长期不同施肥措施下岩溶水稻土可培养细菌群落变化及其主要影响因素

【背景】施肥是目前提高作物产量的较优策略,不同的施肥措施在不同程度上影响土壤肥力和微生物群落结构。【目的】探究岩溶水稻土理化性质变化与细菌群落变化的对应关系,进而反映不同施肥措施对土壤可培养细菌群落的影响。最后选出最优施肥方案,为后续的合理施肥工作提供依据。【方法】对岩溶水稻土进行不施肥、常规施肥、常规施肥加绿肥3种施肥处理,通过对土壤理化性质、可培养细菌群落丰度及多样性变化的研究,探究在不同施肥措施下对岩溶水稻土壤细菌群落的影响。【结果】对比不施肥处理,常规施肥处理下土壤pH值和有机碳含量下降,结合大量研究结果证明,无机肥或氮肥的长期过量施加使土壤pH值下降,常规施肥加绿肥有利于有机碳的积累。分离纯化共得到164株菌,分别来自Actinobacteria、Bacteroidetes、Firmicutes和Proteobacteria。属水平上常规施肥配施绿肥较常规施肥组优势菌属Sphingomonas、Lysobacter的相对丰度增加。细菌群落多样性增加,出现Paenibacillus、Streptomyces和Pseudomonas等特有功能菌属。优势菌属Sphingopyxis、Lysobacter、Paenibacillus、Bosea、Streptomyces、Pseudomonas和Bacillus与TN存在显著正相关,在常规施肥加绿肥处理土壤中增加。【结论】常规施肥加绿肥处理下,固氮、溶磷等功能菌丰度增加,增加土壤肥力,保持土壤养分的可利用性,对作物的增产起重要作用。岩溶水稻土常规施肥配施绿肥处理的效果优于不施肥和常规施肥处理。

Variation of cultivable bacterial community structure and the main influencing factors in karst paddy soil under different fertilization regimes

Background] Fertilization is the better strategy to improve crop yield. Fertilization measures can affect soil fertility and microbial community structure. Objective] The inter-relationship between physicochemical properties and soil culturable bacterial communities will be explored. An optimal fertilization plan will be selected, and the result will provide the basic data for future work. Methods] Three fertilization treatments of no fertilization, conventional fertilization, conventional fertilization and green manure were carried out on karst paddy soil. Based on the study of soil physical and chemical properties, abundance and diversity of cultivable bacterial communities, the effect of different fertilization measures on karst paddy soil was discussed about influence bacterial community. Results] Compared with no fertilization treatment, the soil pH value and organic carbon content decreased along conventional fertilization treatment. Combined with a large number of research results, it proved that the long-term excessive application of inorganic fertilizer or nitrogen fertilizer decreased the soil pH value. The accumulation of organic carbon appeared in conventional fertilization plus green manure. A total of 164 strains of bacteria were obtained by separation and purification, which were from Actinobacteria, Bacteroidetes, Firmicutes and Proteobacteria. At the genus level, the abundance of conventional fertilization combined with green manure was higher than that of the conventional fertilization group of dominant bacteria of Sphingomonas and Lysobacter. The diversity of bacterial communities has increased with the emergence of specific functional bacterial genera such as Paenibacillus, Streptomyces and Pseudomonas. The dominant bacteria Sphingopyxis, Lysobacter, Paenibacillus, Bosea, Streptomyces, Pseudomonas and Bacillus were significantly positively correlated with TN, and they were enriched in soil treated with conventional fertilization and green manure. Conclusion] Under the treatment of conventional fertilization and green manure, the abundance of functional bacteria relating to nitrogen fixation and phosphorus increased which could increase soil fertility and have an important role in increasing crop production. The effect of conventional fertilization combined with green manure treatment on karst paddy soil is better than those with no fertilizer and conventional fertilization treatment.