麦田土壤真菌多样性对麦玉轮作长期秸秆还田和配施有机肥的响应

Responses of soil fungal diversity to long-term straw incorporation and manure application in the field with winter wheat-summer maize rotation

摘要:

【背景】土壤真菌主导田间秸秆腐解的过程，秸秆还田配施有机肥可为真菌提供良好的营养物质。【目的】研究麦玉轮作模式下长期秸秆还田配施有机肥对麦田土壤真菌多样性的影响。【方法】依托山西南部麦玉轮作区长达14年的秸秆还田和施有机肥长期定位试验，采用高通量测序开展土壤真菌群落结构和多样性对不施肥+秸秆清茬(CK)、氮磷化肥+秸秆清茬(NP)、氮磷化肥+秸秆还田(SNP)、氮磷化肥+有机肥+秸秆清茬(NPM)及氮磷化肥+秸秆还田+有机肥(SNPM)的响应差异研究。【结果】秸秆还田和施有机肥处理组的物种丰富度指数、Chao1指数和ACE指数均高于CK。5个处理共产生953个分类操作单元(operational taxonomic units, OTU)，CK、NP、NPM、SNP和SNPM分别具有398、451、472、462和440个OTU。在门水平上共检测出9个菌门，其中子囊菌门(Ascomycota)、毛霉门(Mucoromycota)和担子菌门(Basidiomycota)为3个主要菌门，各处理中所占丰度差异显著；在属水平上共检测出262个真菌属，其中CK丰度较高的3个属为柄孢壳菌属(Podospora) 18.85%、被孢霉属(Mortierella) 16.67%和镰刀菌属(Fusarium) 7.77%；NP、NPM、SNP和SNPM丰度较高的前3个相同属均为Dendrostilbella、毛葡孢属(Botryotrichum)和被孢霉属(Mortierella)，但相对丰度值存在差异。由聚类分析可知，NPM和SNPM群落组成相似度高，归为一类，而CK、NP、SNP各独立为一类。与环境因子间冗余分析发现，TN含量是影响土壤真菌群落结构的关键因子，也受速效磷、pH、速效钾、碱解氮和全磷等环境指标影响。【结论】长期秸秆还田和施有机肥改变了小麦土壤真菌种群结构和多样性。

Abstract:

[Background] Soil fungi dominate the straw decomposition in the field, and straw incorporation and manure application provide nutrients for fungi. [Objective] To study the effect of long-term straw incorporation and manure application on the soil fungal diversity in the field with winter wheat-summer maize rotation. [Methods] Basing on the 14-year location experiment of straw incorporation and manure application in the field with wheat-maize rotation in southern Shanxi province, the study employed high-throughput sequencing to explore the soil fungal community structure and diversity in response to straw incorporation and manure application. The treatments included straw stubble cleaning+unfertilized control (CK), straw stubble cleaning+N and P fertilizers (NP), straw incorporation+N and P fertilizers (SNP), straw stubble cleaning+N and P fertilizers+manure (NPM), and straw incorporation+N and P fertilizers+manure (SNPM). [Results] The richness, Chao1 index, and ACE index of soil fungi in the treatments with straw incorporation and manure were higher than those of CK. A total of 953 OTUs was detected in the five treatment soils. Specifically, CK, NP, NPM, SNP, and SNPM had 398, 451, 472, 462, and 440 OTUs, respectively. A total of 9 fungal phyla were detected, among which Ascomycota, Mucoromycota, and Basidiomycota were dominant and their abundance were significantly different among treatments. A total of 262 fungal genera were detected, among which the three genera with high abundance were Podospora (18.85%), Mortierella (16.67%), and Fusarium (7.77%) in the CK. The top three common genera with high abundance in NP, NPM, SNP, and SNPM were Dendrostilbella, Botryotrichum, and Mortierella, which showed different relative abundance among treatments. According to the cluster analysis, NPM and SNPM with high similarity in fungal community composition and were classified into one category, while CK, NP and SNP were independent categories. The redundancy analysis with environmental factors showed that total nitrogen content was the key factor affecting soil fungal community structure, which was also affected by available phosphorus, pH, available potassium, available nitrogen, and total phosphorus. [Conclusion] Straw incorporation and manure could alter the soil fungal community structure and diversity in the field with winter wheat-summer maize rotation.