覆盖对毛竹林土壤养分、酶活性及微生物群落的影响

Effects of mulching on soil nutrients,enzyme activities and microbial community in Phyllostachys edulis forest

【目的】为退化毛竹林土壤的修复和质量提升提供参考。【方法】以覆盖1 a、覆盖2 a、覆盖3 a、覆盖后恢复2 a、覆盖后恢复5 a及未覆盖的毛竹林地土壤为研究对象,测定土壤脲酶、酸性磷酸酶及过氧化氢酶等土壤酶活性指标,测定土壤有机质、全氮、碱解氮、全磷、速效磷、全钾及速效钾等土壤养分含量及土壤pH值,采用高通量测序技术测定土壤微生物群落组成及多样性,探讨土壤细菌、真菌变化特征及其与土壤养分含量、酶活性的相关性。【结果】覆盖3 a的毛竹林土壤脲酶、酸性磷酸酶活性均低于其他林地类型,覆盖后恢复5 a的0~20 cm土层酶活性均较高。样地土壤细菌类群中酸杆菌门、绿弯菌门、变形菌门、放线菌门为优势菌群,真菌类群中子囊菌门、担子菌门、球囊菌门所占比例较高。覆盖后恢复5 a的40~60 cm土层细菌和真菌的OUT数量较少,Chao1、Simpson及PD-whole tree指数均较小,表明覆盖后林地深层土壤微生物的数量及多样性均受到影响,土壤退化程度较高且恢复缓慢。土壤环境因子对毛竹林土壤细菌门水平的贡献度由高到低排序依次为酸性磷酸酶活性、过氧化氢酶活性、脲酶活性、碱解氮含量、有机质含量、全氮含量、速效磷含量、全磷含量、全钾含量、速效钾含量、pH值,酸性磷酸酶的贡献度最高,为36.73%。土壤环境因子对毛竹林土壤真菌门水平的贡献度由高到低排序依次为过氧化氢酶活性、酸性磷酸酶活性、脲酶活性、有机质含量、碱解氮含量、全氮含量、全钾含量、速效磷含量、速效钾含量、pH值、全磷含量,过氧化氢酶活性的贡献度最高,为34.60%。【结论】覆盖技术改变了毛竹林土壤的养分含量和酶活性,调控了土壤微生物群落的组成及多样性,长期覆盖导致竹林地土壤发生了不同程度的退化,覆盖竹林退化土壤亟待修复。

【Objective】To provide reference for the restoration and quality improvement of degraded Phyllostachys edulis forest soil.【Method】The soil of P.eduli forest mulching for 1 a,2 a,3 a,recovered for 2 a,5 a after mulching and no mulching were taken as the research object,determination of soil enzyme activities such as urease,acid phosphatase and catalase,determination of soil pH,the contents of soil nutrients such as organic matter,total nitrogen,alkalihydrolyzed nitrogen,total phosphorus,available phosphorus,total potassium and available potassium were conducted,and the composition and diversity of soil microbial community were determined by high-throughput sequencing,the change characteristics of soil bacteria and fungi and their correlation with soil nutrients content and enzyme activities were studied.【Result】The soil urease and acid phosphatase activities of the P.edulis forest mulching for 3 a were lower than those of other forest land types;the soil enzyme activities in 0-20 cm surface soil of recovered for 5 a after mulching were higher.The bacterial groups Acidobacteria,Chloroflexi,Proteobacteria,and Actinomycetes were the dominant bacterial groups in the plots,and the fungal groups Ascomycota,Basidiomycota,and Glomusocota accounted for a higher proportion.The number of bacteria and fungi OUT was small,and Chao1,Simpson and PD-whole tree indices in 40-60 cm soil layer of the P.edulis forest recovered for 5 a after mulching were all small,indicating that the number and diversity of soil microorganisms in the deep layer of the forest land were affected and the degree of degradation was higher,and the soil quality recovery was slow.The contribution degree of soil environmental factors to soil bacteria phylum level in P.edulis forest from high to low was in order of acid phosphatase,catalase,urease,alkali-hydrolyzed nitrogen,organic matter,total nitrogen,available phosphorus,total phosphorus,total potassium,available potassium,pH,and the highest contribution of acid phosphatase was 36.73%.The contribution degree of soil environmental factors to soil fungal phylum level in P.edulis forest from high to low was in order of catalase,acid phosphatase,urease,organic matter,alkali-hydrolyzed nitrogen,total nitrogen,total potassium,available phosphorus,available potassium,pH,total phosphorus,with the highest contribution of catalase was 34.60%.【Conclusion】Mulching technology changes the soil nutrient content and enzyme activities,and regulates the composition and diversity of soil microbial community.Long-term mulching leads to the degradation of P.edulis forest land to varying degrees,and the degraded soil of mulching P.edulis forest needs to be repaired urgently.