吉林省中部地区退耕还林对黑土土壤细菌和真菌群落结构的影响

为揭示退耕还林对土壤细菌和真菌群落结构的影响，以吉林省城东村耕地及其相邻退耕20年的杨树林地为研究对象，采用高通量测序技术分析细菌和真菌的多样性、群落结构特征和共现性关系。结果表明：退耕还林后，土壤细菌多样性降低，真菌的多样性及丰富度均显著增加。退耕后细菌的丰度变化并非全部体现在优势物种上，放线菌门（Actinobacteriota）丰度由28.19%减少到26.12%，而酸杆菌门（Acidobacteriota）、变形菌门（Proteobacteria）丰度分别从16.83%、15.94%增加至22.50%、18.42%，真菌的丰度变化主要体现在优势物种上，子囊菌门（Ascomycota）丰度由46.54%减少到35.93%，担子菌门（Basidiomycota）丰度由41.34%减少到31.52%，而被孢霉门（Mortierellomycota）丰度则由7.14%增加到24.22%。退耕还林前后细菌和真菌群落结构均发生了显著变化，真菌在退耕前后的差异更大。土壤真菌、细菌的共现网络在还林后具有更多的节点数及边数，共现性关系更复杂，连结性更高。冗余分析（RDA）表明土壤细菌和真菌群落结构均受土壤pH、有机质、速效钾、碱解氮、速效磷的影响（P<0.05）。研究表明，退耕还林显著影响吉林省中部地区黑土土壤细菌和真菌群落结构及多样性，退耕后土壤微生物的相互关系更复杂，抗干扰能力更强。

Effects of the Grain for Green Project on bacteria and fungi community structure in the black soil of central Jilin Province, China

To determine the effect of the Grain for Green Project on the soil bacteria and fungi community structure, soil samples were collected from arable land in Chengdong Village, Jilin Province, and its adjacent poplar woodlands that have been restored for 20 years. The diversity, community structure characteristics, and networks of bacteria and fungi were analyzed using high-throughput sequencing technology. Our results showed that the diversity of soil bacteria decreased, whereas the diversity and abundance of fungi increased significantly after reforestation. Changes in the abundance of bacteria after farmland retirement were not reflected in the dominant species. The abundance of Actinobacteriota decreased from 28.19% to 26.12%. However, the abundances of Acidobacteriota and Proteobacteria increased from 16.83% and 15.94% to 22.50% and 18.42%, respectively. Changes in the abundance of fungi were mainly reflected in the dominant species; the abundance of Ascomycota decreased from 46.54% to 35.93%, Basidiomycota decreased from 41.34% to 31.52%, and Mortierellomycota increased from 7.14% to 24.22%. Both bacterial and fungal communities were significantly different after reforestation; however, the difference in fungal communities was greater. The network analysis of soil bacteria and fungi showed more nodes and edges, complex co-occurrence relationships, and higher connectivity after restoration. Redundancy analysis showed that soil bacterial and fungal community structures were affected by soil pH, organic matter, available potassium, available nitrogen and available phosphorus(P<0.05). The results indicated that the community structure and diversity of soil bacteria and fungi in the black soil of central Jilin Province were significantly affected by the Grain for Green Project, and the networks of fungi and bacteria were more complex and more resistant to interference after reforestation.