环青海湖地区两种引种禾本科牧草根际真菌群落对有机肥的响应

本研究以环青海湖地区引进的两种禾本科牧草'川草2号’老芒麦(Elymus sibiricus 'Chuancao No.2’)和'阿坝’垂穗披碱草(Elymus nutans 'Aba’)为研究对象，通过田间试验，采用ITS rDNA Illumina高通量测序技术和分子生态网络的方法，分析施用有机肥后两种牧草生长及根际真菌群落结构变化。结果显示，与对照相比，有机肥显著增加两种牧草的地上及地下生物量，降低牧草茎叶比(P<0.05)；有机肥处理改变了土壤理化性质，提高全氮(TN)和有机碳(SOC)含量(P<0.05)，降低土壤pH。土壤真菌群落结构表明：有机肥降低老芒麦根际主要优势菌和次要优势菌的相对丰度；提高披碱草根际赤霉菌(Gibberella)、内生真菌属(Preussia)相对丰度。RDA结构显示pH和SOC是驱动微生物变化的主要环境因子(P<0.01)，有机肥添加重新构建了土壤真菌群落间的网络关系。高寒地区短期施加有机肥明显促进牧草生长，提高土壤肥力，改变微生物群落结构。

Responses of Rhizosphere Fungal Communities of Two Introduced Gramineous Grasses to Organic Fertilizer in the Qinghai Lake Region

In this study,two species of grasses introduced in the Qinghai Lake area, Elymus sibiricus 'Chuancao No.2'and Elymus nutans 'Aba',were used in the field trials to analyze the changes in growth and rhizosphere fungal community structure after organic fertilization using ITS rDNA Illumina high-throughput sequencing technology and molecular ecological network. The results showed that organic fertilizer significantly increased the above- and below-ground biomass and decreased the stem-to-leaf ratio of both forages compared with the control (P<0.05);organic fertilizer treatment changed the soil physicochemical properties,increased the content of total nitrogen (TN) and organic carbon (SOC) (P<0.05),and decreased the soil pH. The redundancy analysis (RDA) structure showed that pH and SOC were the main environmental factors driving microbial changes (P<0.01),and organic fertilizer addition reconstructed the network relationships among soil fungal communities. Short-term application of organic fertilizer in alpine areas significantly promoted forage growth,improved soil fertility,and changed microbial community structure.