绿肥配施氮肥对岩溶区稻田土壤微生物群落的影响

Effect of the combination of green manure with nitrogen fertilizer on microbial community in karst paddy soil

摘要:

绿肥参与耕作改制是土壤培肥及作物增产的有效措施，对土壤微生物群落结构及多样性的影响至关重要。【目的】研究绿肥配施氮肥对岩溶区稻田土壤微生物群落结构的影响，阐明微生物、土壤生态环境因子及作物产量的相互关系，为岩溶稻区绿肥替代氮肥提供理论依据和数据支撑。【方法】以典型岩溶稻田土壤为研究对象，设置冬闲+不施氮肥(CK)、冬闲+氮肥(N)、绿肥+不施氮肥(M)、绿肥+氮肥(MN)4个处理，通过3年田间定位试验，对土壤微生物进行高通量测序，解析不同施肥处理对细菌和真菌群落的影响。【结果】与CK相比，MN处理显著提高了早稻产量，提升了土壤有机质、全氮、碱解氮和速效钾含量，降低了速效磷含量。MN处理显著提高细菌群落丰富度及多样性，而真菌群落丰富度和多样性在MN处理有降低趋势。岩溶稻田土壤优势细菌类群主要为Chloroflexi、Proteobacteria和Acidobacteria等，优势真菌类群主要为Ascomycota、Basidiomycota和Zygomycota等。冗余分析(RDA)结果表明，土壤速效钾是影响土壤细菌群落组成的关键环境因子。共现网络分析结果表明，细菌-真菌群落交互关系主要以正相互作用为主，细菌主要类群为Chloroflexi和Proteobacteria，真菌主要类群为Ascomycota和Basidiomycota。【结论】绿肥翻压配施氮肥有利于改善土壤养分含量，其效果优于单施绿肥或单施氮肥，且有利于改善土壤微生物学性状，为岩溶区绿肥替代氮肥提供了数据支撑。

Abstract:

Application of green manure is an effective measure to improve soil fertility and crop yield, which is very important to the structure and diversity of soil microbial community. [Objective] To study the effect of green fertilizer combined with nitrogen fertilizer on microbial community structure in karst paddy soil, clarify the interaction among microorganisms, soil environmental factors, and crop yield, and thereby provide theoretical basis and evidence for the replacement of nitrogen fertilizer with green manure in karst area. [Methods] A three-year experiment was carried out on the typical karst paddy soil with the following four treatments: winter fallow + no nitrogen fertilizer (CK), winter fallow + nitrogen fertilizer (N), green manure + no nitrogen fertilizer (M), and green fertilizer + nitrogen fertilizer (MN). Soil microorganisms were sequenced with high throughput sequencing technology to analyze the effect of different fertilization treatments on bacterial and fungal communities. [Results] Compared with CK, MN significantly increased the early rice yield, and the content of soil organic matter (SOM), total nitrogen (TN), available nitrogen (AN), and available potassium (AK), and decreased the content of available phosphorus (AP). Compared with other treatments, MN significantly raised soil bacterial richness and diversity, while the richness and diversity of fungal community decreased in MN. Chloroflexi, Proteobacteria, and Acidobacteria dominated the bacteria, and Ascomycota, Basidiomycota, and Zygomycota were dominant fungal taxa in the karst paddy soil. Redundancy analysis (RDA) revealed that soil AK was the key factor affecting the composition of soil bacterial community. Co-occurrence network analysis indicated that there were mostly synergistic and reciprocal relationships among microorganisms. The main bacterial groups were from Chloroflexi and Proteobacteria, and the main fungal groups were Ascomycota and Basidiomycota. [Conclusion] The combined use of green manure and nitrogen fertilizer can help increase soil nutrient content, and the effect is better than that of the application of chemical green alone or nitrogen fertilizer alone. Moreover, the combination can improve soil microbiological properties. This study provides evidence for the substitution of green fertilizer for nitrogen fertilizer in karst area.