| 微生物群落驱动AM真菌、生物炭及联合改良沙化土壤作用潜力 |
| 摘要点击 2422 全文点击 781 投稿时间：2020-08-14 修订日期：2020-09-14 |
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| 中文关键词 微生物群落 丛枝菌根真菌 生物炭 联合改良 沙化土壤 改良机制 |
| 英文关键词 microbial community arbuscular mycorrhizal (AM) fungi biochar combined amendment sandy soil improvement mechanism |
| 作者 | 单位 | E-mail | | 张哲超 | 内蒙古大学生态与环境学院, 蒙古高原生态学与资源利用教育部重点实验室, 内蒙古草地生态学重点实验室, 呼和浩特 010021 | chao657564313@163.com | | 杨久扬 | 内蒙古大学生态与环境学院, 蒙古高原生态学与资源利用教育部重点实验室, 内蒙古草地生态学重点实验室, 呼和浩特 010021 | | | 郝百惠 | 内蒙古大学生态与环境学院, 蒙古高原生态学与资源利用教育部重点实验室, 内蒙古草地生态学重点实验室, 呼和浩特 010021 | | | 郝利君 | 内蒙古大学生态与环境学院, 蒙古高原生态学与资源利用教育部重点实验室, 内蒙古草地生态学重点实验室, 呼和浩特 010021 | | | 罗俊清 | 内蒙古大学生态与环境学院, 蒙古高原生态学与资源利用教育部重点实验室, 内蒙古草地生态学重点实验室, 呼和浩特 010021 | | | 李雪 | 内蒙古大学生态与环境学院, 蒙古高原生态学与资源利用教育部重点实验室, 内蒙古草地生态学重点实验室, 呼和浩特 010021 | | | 刁风伟 | 内蒙古大学生态与环境学院, 蒙古高原生态学与资源利用教育部重点实验室, 内蒙古草地生态学重点实验室, 呼和浩特 010021 | | | 张璟霞 | 内蒙古大学生态与环境学院, 蒙古高原生态学与资源利用教育部重点实验室, 内蒙古草地生态学重点实验室, 呼和浩特 010021 | | | 郭伟 | 内蒙古大学生态与环境学院, 蒙古高原生态学与资源利用教育部重点实验室, 内蒙古草地生态学重点实验室, 呼和浩特 010021 | ndguowei@163.com |
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| 中文摘要 |
| 沙化土壤作为土地荒漠化的重要过渡形式，实现其有效恢复对减缓土地荒漠化进程意义重大.本研究显示，丛枝菌根（arbuscular mycorrhizal，AM）真菌和生物炭已应用于沙化土壤改良过程，但二者联合对沙化土壤改良影响研究较少；此外，细菌和真菌群落在沙化土壤改良过程中的作用尚不清楚.采用温室盆栽试验的方法，分别设置对照处理（CK）、单独接种AM真菌处理（RI）、单独施加生物炭处理（BC）和二者联合改良处理（BC_RI），研究不同改良方式对小果白刺（Nitrariasi birica Pall.）菌根侵染率、生物量、矿质营养元素（N、P、K、Ca和Mg）含量及土壤有机碳、营养元素（全N、全P和全K）、水稳性团聚体组成影响.采用高通量测序技术，考察细菌和真菌群落在沙化土壤改良过程中的作用，结合多元分析手段，探究不同改良方式改良作用机制，旨在为合理有效改良沙化土壤提供基础数据和理论依据.结果表明，接种处理（RI和BC_RI）小果白刺根系均观察到明显的菌根侵染现象，但RI和BC_RI处理间菌根侵染率无显著性差异.与CK相比，RI处理显著增加了小果白刺地上部生物量和地上部N、K、Ca和Mg含量，BC和BC_RI处理显著增加了小果白刺地上部、根部生物量及N、P、K、Ca和Mg含量；BC_RI处理与RI和BC相比，根部生物量及P、K、Ca和Mg含量显著增加.与CK相比，BC和BC_RI处理显著增加了土壤有机碳含量，RI处理使得土壤全N含量显著增加了152.54%，BC处理使得土壤全P和全K含量分别显著降低了12.5%和18.18%.各处理0.25~0.05 mm粒径土壤团聚体比例最高，BC_RI处理能够显著促进大粒径（>0.25 mm）土壤团聚体形成.与CK相比，RI和BC_RI处理显著降低细菌、真菌群落Sobs指数和Shannon指数；各处理细菌及真菌菌门组成及丰度存在显著差异性.RDA及网络分析结果显示，AM真菌、生物炭及二者联合改良方式对土壤基质环境及土壤微生物群落结构影响显著，不同改良方式下微生物分子生态网络关系发生显著变化，不同改良处理中核心物种组成具有差异性；BC和BC_RI较RI处理，网络连接密集程度更高且核心物种组成更丰富；生物炭与AM真菌联合，弱化了Rhizophagus intraradices的核心作用，并增强其他微生物（特别是细菌菌种）的核心地位.SEM结果显示，AM真菌和生物炭施用通过直接影响土壤细菌和真菌群落结构，进而实现对植物生长及土壤性质变化的影响，微生物群落结构差异（特别是微生物间的互作关系变化）是导致土壤改良效果差异的主要驱动力.综上所述，不同改良方式对沙化土壤改良效果影响具有差异性，微生物群落在土壤改良过程中具有关键影响作用，AM真菌和生物炭联合对加速沙化土壤生态恢复具有潜在优势和应用价值. |
| 英文摘要 |
| Sandy soils are considered as a significant transition phase to desertification. The effective recovery of sandy soils is of great significance to mitigate the desertification process. Some studies have shown that arbuscular mycorrhizal (AM) fungi and biochar improved the sandy soil, but there have been very few studies regarding the combined effects of AM fungi and biochar amendments on sandy soil improvement. Additionally, the roles of the bacterial and fungal community during the process of sandy soil improvement remain unclear. A greenhouse pot experiment with four treatments, including a control (CK, no amendment), single AM fungi-assisted amendment (RI), single biochar amendment (BC), and combined amendment (BC_RI, biochar plus AM fungi), was set up. This study investigated the effects of different amendment methods on the Nitrariasi birica mycorrhizal colonization, biomass, nutrient (N, P, K, Ca, and Mg) content, soil organic carbon, soil nutrient (TN, TP, and TK) content, and soil water-stable aggregate composition. High throughput sequencing technology was used to investigate the roles of the bacterial and fungal communities during the process of sandy soil improvement. Combined with multiple analysis methods, the improvement mechanisms of different amendment methods were explored. The aim was to provide basic data and scientific basics for reasonably and effectively improving sandy soils. The results indicated that a significant mycorrhiza colonization was observed in the inoculation (RI and BC_RI) treatments, but there was no substantial difference in the mycorrhiza colonization with the RI and BC_RI. Compared with the CK, the shoot biomass and shoot element (N, K, Ca, and Mg) contents were significantly increased in the RI, and the shoot element (N, P, K, Ca, and Mg) contents were significantly increased in the BC and BC_RI; compared with the RI and BC, the root biomass and the root element (P, K, Ca, and Mg) contents were significantly increased in the BC_RI. Compared with the CK, the soil organic carbon contents were significantly increased in the BC and BC_RI, the soil TN contents were significantly increased by 152.54%, and the soil TP and TK contents were significantly decreased by 12.5% and 18.8%, respectively. The proportion of soil aggregates with particle sizes of 0.25-0.05 mm was the highest in each treatment, and the large particle size (>0.25 mm) soil aggregate was significantly increased in the BC_RI. Compared with the CK, the Sobs and Shannon indices of the bacterial/fungal community were significantly decreased in the RI and BC_RI. There was a difference in the microbial community compositions and abundance in the various treatments. The results of the RDA and network analysis were as follows:the effects of AM fungi, biochar, and combined amendment on the soil environment and microbial community structure were significant; in the different amendment treatments, the relationship of the microbial molecular ecological network was significantly changed, and the composition of the core species varied; compared with the RI, there was a higher network connection degree and a richer core species composition in the BC and BC_RI; moreover, the essential role of Rhizophagus intraradices was weaken and the core roles of the other microorganisms (especially bacterial species) were enhanced under the combined effects of biochar and AM fungi. The SEM results demonstrated that the application of AM fungi and biochar could directly affect the bacteria/fungi community structure, and further affect the plant growth and soil properties. The differences in the microbial community structure (especially the change in the microbial interaction) were the key driving factors that led to the difference in the soil improvement effectiveness. In summary, the effects of the different amendment methods on the improvement effectiveness of sandy soils varied. The microbial community played key roles in the process of sandy soil improvement, and there were potential advantages and applications in accelerating the ecological restoration of sandy soils under the combined AM fungi and biochar amendment. |
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