压砂西瓜连作土壤生物学特性和理化性质变化

Changes of soil biological and physiochemical properties in continuous cropping of watermelon in sandy loam soil

利用Illumina MiSeq测序和定量PCR技术测定宁夏中卫市兴仁镇压砂西瓜连作10 a的土壤微生物群落结构变化,结合土壤理化性质分析压砂西瓜连作下土壤生态系统响应.结果表明,随连作年限的增加,土壤pH、养分含量和土壤酶活性都逐渐下降,土壤容重呈增加趋势;连作导致压砂西瓜土壤细菌群落多样性和丰富度显著降低,真菌多样性和丰富度显著增加;细菌和真菌主要优势物种组成发生了变化,细菌中变形菌门相对丰度减少,占真菌群落总丰度的80%以上的子囊菌门和担子菌门的相对丰度随连作年限延长有差异;细菌群落生物量显著下降,真菌群落生物量逐渐增加,细菌与真菌生物量比值随连作年限的延长持续显著减小.土壤微生物群落的变化可灵敏反映连作压砂西瓜的土壤质量问题.

Using Illumina Miseq sequencing and quantitative PCR technology,the changes in soil microbial community structures were determined within 10 years of continuous cropping of watermelon in sandy loam soil in Xingren Town of Zhongwei City.Combined with the changes in soil physiochemical properties,the response of soil ecosystem to watermelon continuous cropping in sandy loam soil was analyzed.With the increase of continuous cropping years,soil pH,nutrient contents and soil enzyme activities decreased gradually,while soil bulk density showed an increasing trend;continuous cropping led to a significant decrease in soil bacterial community diversity and richness,but a significant increase in fungal diversity and richness;the main dominant species in bacterial and fungal communities also changed,the relative abundance of Proteobacteria decreased in the continuous cropping soil and that of Ascomycota and Basidiomycota,which accounted for more than 80%of the total abundance of fungal community,also underwent variations with the extension of continuous cropping years.The biomass of bacterial community decreased significantly,while that of the fungal community increased gradually and the ratio of bacteria to fungi continued to decrease significantly with the extension of continuous cropping years,with the conclusion that changes in soil microbial communities could sensitively reflect the soil quality of continuous cropping watermelon in sandy loam soil.