摘要:为探索秸秆还田与施肥方式2种农田措施对水稻-小麦（稻麦）轮作土壤微生物群落的影响，阐释其对土壤细菌和真菌群落结构和多样性的影响机制，本研究通过7年稻麦轮作长期定位监测试验，设置无肥空白（CK）、常规施肥（RT）、秸秆还田+常规施肥（RS）和秸秆还田+缓释肥（SS）4个处理，采用Illumina Miseq高通量测序技术，分析土壤细菌和真菌群落结构和多样性，探索影响微生物群落的主控环境因子。结果表明，SS作物产量在2016年和2017年分别比RT显著提高11.6%和8.2%（水稻）、4.8%和3.6%（小麦），与RS无显著差异。相比RT，秸秆还田处理显著降低了土壤pH，提升了土壤有机碳和铵态氮含量；与RS相比，SS处理提高了铵态氮含量。秸秆还田处理提升了真菌群落多样性，但对细菌群落多样性无显著影响。SS与RS在细菌真菌群落多样性方面均无显著差异。相关性分析表明，细菌群落多样性与土壤pH呈负相关，与总氮含量呈正相关；真菌群落多样性则与土壤有机碳含量显著正相关。NMDS分析表明，施肥对于细菌群落结构影响较大（55.61%），真菌群落结构则对秸秆还田响应更明显（26.94%）。与RT相比，秸秆还田显著提升了细菌放线菌门、绿弯菌门、厚壁菌门的相对丰度，同时显著提升了真菌中子囊菌门的相对丰度，降低了担子菌门和接合菌门的相对丰度，加强了土壤碳氮循环能力并抑制了病原菌。SS与RS相比，仅提升了真菌中子囊菌门的相对丰度。综上，秸秆还田配施缓释肥有助于维持或者提高土壤养分有效性、作物产量及细菌真菌群落多样性，可以促进土壤碳氮循环。
关键词:土壤微生物/
群落结构/
土壤养分/
秸秆还田/
缓释肥/
高通量测序
Abstract:Straw returning and slow-release fertilizers are widely used in agriculture to reduce non-point source pollution and improve nitrogen use efficiency. However, there are few studies on the effect of straw return combined with slow-release fertilizers on the soil microbial community. This study determined how straw returning combined with fertilization affected the bacterial and fungal communities in rice-wheat rotation soil and the underlying mechanisms. Based on a seven-year rice-wheat rotation system monitoring experiment, four treatments were selected: no fertilizer (CK), regular chemical fertilization (RT), straw returning combined with chemical fertilization (RS), and straw returning combined with slow-release fertilizer (SS). The Illumina MiSeq platform was used to evaluate the community structure and diversity of soil bacteria and fungi and to detect the primary environmental factors affecting the microbial community. The results showed that the SS rice and wheat yields in 2016 and 2017 were significantly higher than the RT yields (by 11.6% and 8.2% in rice, and 4.8% and 3.6% in wheat, respectively); there was no difference between SS and RS yields. Compared to RT, straw returning significantly decreased soil pH and increased soil organic carbon (SOC) and ammonium nitrogen (NH4+-N) contents; SS had more NH4+-N than RS. The fungal community diversity was higher with straw returning than with RT, but there was no difference in the bacterial community diversity among fertilization treatments; the bacterial and fungal community diversities were the same between RS and SS. Correlation analysis showed that the bacterial community diversity was negatively correlated with pH and positively correlated with soil total nitrogen content, while the fungal community diversity was positively correlated with SOC. Non-metric multidimensional scaling analysis showed that fertilization had a greater effect on the bacterial community structure (55.61%), and straw returning had a greater effect on the fungal community structure (26.94%). Proteobacteria, Chloroflexi, and Acidobacteria (in successive order) were the dominant phyla across all treatments, accounting for 66.07%–71.76% of the total bacterial sequence data. Ascomycota, Basidiomycota, and Zygomycota (in successive order) were the dominant phyla across all treatments, accounting for 88.05%–89.04% of the total fungal sequence data. Compared with RT, the treatments with straw returning significantly increased the relative abundance of Actinobacteria, Chloroflexi, and Firmicutes in the bacterial community, and significantly increased the relative abundance of Ascomycota and decreased the relative abundance of Basidiomycota and Zygomycota in the fungal community. Ecological function analysis of these bacterial and fungal communities showed that straw returning may enhance soil carbon and nitrogen cycling and inhibit pathogens. Compared with RS, SS only increased the relative abundance of Ascomycota in the fungal community; there were no other differences between the relative abundances of bacteria and fungi in RS and SS at the phylum level. Straw returning with slow-release fertilizers can help maintain or improve soil nutrient availability, crop yield, and the diversity of bacterial and fungal communities and can promote soil carbon and nitrogen cycling.
Key words:Soil microorganism/
Community structure/
Soil nutrient/
Straw returning/
Slow release fertilizer/
High throughput sequencing
PDF全文下载地址:
http://www.ecoagri.ac.cn/article/exportPdf?id=fd721088-0b0a-41b4-9de8-753723c8f11b
