设施番茄种植年限对土壤理化性质及微生物群落的影响

为探究设施番茄种植年限对土壤理化性质和微生物群落影响，以种植1~3 a、5~7 a和>10 a的设施番茄耕层土壤为研究对象，采用常规分析方法测定土壤理化性质，采用Illumina NovaSeq高通量测序技术测定土壤微生物群落结构和多样性.结果表明，随着种植年限的延长，土壤容重和pH呈现降低趋势，最大持水量和有机质等指标逐渐增加，电导率（EC值）和全盐含量先降低后升高，显现出土壤次生盐渍化的趋势，其中土壤有机质、全氮和速效钾含量不同连作年限间差异显著（P<0.05）.土壤碱性磷酸酶在种植1~3 a与5~7 a存在显著性差异.各处理间真菌群落相对丰度存在显著性差异，Simpson指数和Shannon指数先升高后降低，Chao1指数逐渐降低；在属水平上，随种植年限的增加，链霉菌属（Streptomyces）等有益细菌群落相对丰度升高成为优势菌属；曲霉菌属（Aspergillus）和Pseudaleuria等致病真菌群落相对丰度逐渐增加成为优势菌属.冗余分析表明设施番茄种植年限与速效钾、速效氮呈显著正相关关系.研究认为，随种植年限的延长，设施番茄土壤次生盐渍化加重、氮磷钾养分累积和微生物群落失衡，导致设施番茄连作障碍.

Effects of Tomato Planting Years on Soil Physical and Chemical Properties and Microbial Communities

Long-term continuous cropping of facility soils could influence soil properties; however, the differences in soil properties among different continuous cropping years are still not well understood. The objective of this study was to explore the effects of continuous cropping years of tomato on the physical and chemical properties and biological characteristics of facility soil. Conventional analysis, high-throughput sequencing, and other methods were used to examine the soil physicochemical properties, soil microbial community diversity, and enzyme activities in facility soil after continuous tomato cropping for 1-3 years, 5-7 years, and more than 10 years. As the continuous tomato cropping years increased, soil bulk density and pH decreased; soil maximal water holding capacity increased; and organic matter, total nitrogen, and total phosphorus accumulated. As continuous cropping years increased, the total salt and EC value decreased with continuous cropping for 5-7 years and increased from 5-7 years to more than 10 years continuous cropping and showed a trend of secondary soil salinization. There was a significant increase in alkaline phosphatase for 1-3 years to 5-7 years continuous tomato cropping. There were significant differences in fungal community abundance among different cropping years. The Simpson index and Shannon index of fungi showed a trend of increasing first and then decreasing with the extension of continuous cropping years and reached the maximum value at 5 years of continuous cropping. The Chao1 index decreased continuously following the cropping years. As continuous cropping years increased, Streptomyces became the dominant bacteria, and Aspergillus and Pseudaleuria became the dominant fungi. The key factors affected by continuous cropping years were available potassium and available nitrogen based on the redundancy analysis. The results of this study lay the foundation for future research on the influence of continuous cropping years on the health of facility soil.