苜蓿连作对盐碱土壤微生物群落结构的影响

Effects of Alfalfa Continuous Cropping on Microbial Community Structure in Saline-alkali Soil

为研究苜蓿连作栽培对土壤养分质量及根际微生物群落结构的影响,采用高通量测序技术,以4年生苜蓿根际土壤为研究对象,对其中的细菌及真菌群落结构进行了研究,同时分析了不同环境因子对微生物群落变化的贡献,为苜蓿改良土壤生态环境提供理论依据。试验结果表明:种植苜蓿可以降低土壤pH值,提高土壤中有机质和碱解氮含量,增加幅度分别为54.33%和24.93%。土壤中酸杆菌门、放线菌门和芽单胞菌门等细菌相对丰度增加了0.26%~6.39%,变形菌门、拟杆菌门、厚壁菌门和硝化螺旋菌门细菌相对丰度降低了0.06%~7.63%。真菌门类中子囊菌门、新美鞭菌门、毛霉门、球囊菌门、壶菌门、油壶菌门和丝足虫门(Cercozoa)比例提高了4.00%~225.00%,担子菌门和Aphelidiomycota所占比例分别降低了14.45%和80.00%。与环境因子的相关性分析表明,土壤中影响土壤细菌群落变化的主要环境因子为有机质、碱解氮和速效钾。结合不同微生物群落功能特性可以得出,苜蓿连作可以提高土壤养分含量及改善生态环境,提高土壤抗逆能力,适宜在盐碱地区推广。

In order to explore the effects of alfalfa continuous cropping on soil nutrient quality and rhizosphere microbial community structure,the bacterial and fungal community structure in rhizosphere soil of four-year-old alfalfa was studied by high-throughput sequencing technology,and the contribution of different environmental factors to the change of micro-bial community was analyzed,which provided theoretical basis for improving soil ecological environment of alfalfa.The re-sults showed that compared with the control,alfalfa planting decreased the soil pH value and increased the content of organ-ic matter and available nitrogen by 54.33%and 24.93%,respectively.The relative abundance of Acidobacterium,Actino-mycetes and Bacillus in soil increased by 0.26%-6.39%,while the relative abundance of Proteus,Bacteroides,Scleren-chyma and Nitrifying spirochetes decreased by 0.06%-7.63%.The proportions of Neutrocystis,Neoflagella,Mucor,Bal-loon,Potamopsis,Oil Potamopsis and Coccozoa increased from 4.00%to 225.00%,while the proportions of Basidiomycota and Aphelidiomycota decreased by 14.45%and 80.00%,respectively.The correlation of environmental factors showed that the main environmental factors affecting the change of soil bacterial community were organic matter,alkali-hydrolyzed nitrogen and available potassium.Combined with the functional characteristics of microbial community,it can be concluded that alfalfa continuous cropping can improve soil nutrients,ecological environment and soil stress resistance,which is suit-able for planting in saline-alkali areas.