不同轮作模式下作物根际土壤养分及真菌群落组成特征

Characteristics of Soil Nutrients and Fungal Community Composition in Crop Rhizosphere Under Different Rotation Patterns

为研究宁夏中部干旱带不同轮作模式下土壤养分及真菌群落组成的特征,以谷子轮作大豆(MRG)、轮作籽粒苋(MRA)、轮作藜麦(MRQ)及谷子连作(CK)为对象,测定了土壤养分含量,并利用Illumina MiSeq高通量测序平台测定了土壤真菌的ITS变异区序列.结果表明,不同轮作模式对土壤养分的影响存在差异.3种轮作模式下土壤pH和电导率均有所下降,土壤全氮、全钾、全磷和有机质含量均上升,OTUs数和α多样性指数均高于连作.真菌群落组成研究结果显示,子囊菌门(Ascomycota)为4种模式下的优势菌群.聚类分析显示MRA和MRG的真菌属组成最为相似,其次是MRQ,CK与3种轮作模式相差较大.相关性分析显示,土壤养分与几种优势真菌属呈显著相关性(P<0.05或P<0.01),土壤全氮、全钾、硝态氮和有机质含量是影响土壤真菌群落最主要的因子.主成分分析(PCA)表明,MRG轮作模式优于MRA和MRQ模式.综上所述,轮作提高了真菌群落多样性指数,改变了土壤真菌群落结构,改善了土壤肥力状况,其中以谷子与大豆轮作效果最佳,建议将谷豆轮作作为中部干旱带杂粮产业中主要的轮作模式之一进行推广.

To study the characteristics of soil nutrients and fungal community composition under different rotation patterns in the arid zone of central Ningxia,we used millet rotation soybean(MRG),rotation grain amaranth(MRA),rotation quinoa(MRQ),and continuous millet rotation(CK)as the objects.The soil nutrient content was determined,and the sequence of the ITS variation region of soil fungi was determined using the Illumina MiSeq high-throughput sequencing platform.The results showed that the effects of different rotation patterns on the soil nutrients were different.The soil pH and electrical conductivity decreased under three rotation patterns,and the soil total nitrogen,total potassium,total phosphorus,and organic matter contents increased.The number of OTUs andαdiversity index was higher than those of continuous millet rotation.The results of the fungal community composition study showed that Ascomycota was the dominant flora in 4 patterns.The cluster analysis showed that the fungal genus composition of MRA and MRG was the most similar,followed by MRQ,and that of CK was significantly different with the other three rotation patterns.A correlation analysis showed that the soil nutrients were significantly correlated with several dominant fungal genera(P<0.05 or P<0.01).Further,the soil total nitrogen,total potassium,nitrate nitrogen,and organic matter contents were the most important factors influencing the soil fungal communities.Principal component analysis(PCA)showed that the MRG rotation patterns were better than those of the MRA and MRQ patterns.In summary,crop rotation improved the polytrophic index of the fungal community,changed the soil fungal community structure,and improved soil fertility.Among,the millet and soybean rotation were the best,and we have suggested to promote cereal rotation as one of the main rotation patterns in the cereal industry in the central dry zone.