作物轮作对谷田土壤理化性质及谷子根际土壤细菌群落的影响

采用谷子连作(Si-Si-Si)、马铃薯-玉米-谷子轮作(St-Zm-Si)、玉米-大豆-谷子轮作(Zm-Gm-Si)和大豆-马铃薯-谷子轮作(Gm-St-Si)四种种植模式进行定位试验,研究轮作对土壤理化性质、土壤酶活性、谷子产量和根际细菌群落结构的影响。结果显示,与连作相比,Gm-St-Si轮作模式下土壤的pH值升高,碱解氮、有效磷、速效钾和有机质含量增加,土壤过氧化氢酶、多酚氧化酶、纤维素酶和蔗糖酶活性提高,谷子产量显著增加;利用Illumina MiSeq测序技术对谷子根际土壤细菌群落结构进行分析,发现三个轮作处理的OTU数目和多样性指数均高于连作,轮作与连作的细菌群落结构与组成存在明显差异,其中Gm-St-Si处理含有丰富的疣微菌门、酸杆菌门和浮霉菌门,高丰度菌包括Planctomyces、Gemmata、Flavisolibacter、Luteolibacter等。综上表明,大豆-马铃薯-谷子轮作能改善谷田生态环境,提高土壤肥力,促进土壤微生物多样性,使谷子产量增加。

Effects of crop rotation on soil physicochemical properties and bacterial community of foxtail millet rhizosphere soil

In the present study, four crop systems including continuous cropping millet (Si-Si-Si), potato-corn-millet rotation (St-Zm-Si), corn-soybean-millet rotation (Zm-Gm-Si), and soybean-potato-millet rotation (Gm-St-Si) were conducted to investigate the influence of crop rotation on soil physical and chemical properties, soil enzyme activities, foxtail millet yield and rhizosphere bacterial community compositions. Our results showed that Gm-St-Si rotation promoted soil pH value and increased the content of alkaline hydrolysis nitrogen, available phosphorus and potassium, and organic matter. The same trend was observed in the activities of catalase, polyphenol oxidase, cellulase and sucrase enzymes in soils. In addition, crop yield was markedly increased after Gm-St-Si rotation cropping. Foxtail millet rhizosphere bacterial community compositions were also investigated using the high throughput illumina sequencing. The results showed that there was significant difference in the rhizosphere bacterial community compositions between rotation and continuous cropping. Soil samples of crop rotations occupied more OTU and showed higher diversity than that of the continuous cropping. Compared to the continuous cropping soil, Gm-St-Si rotation soil harbored higher abundance of Verrucomicrobia, Acidobacteria and Planctomycetes, as well as Planctomyces, Gemmata, Flavisolibacter, and Luteolibacter. Taken together, it was concluded that Gm-St-Si rotation could improve soil ecological environment, promote soil fertility, enhance soil microbial diversity, and thus increase the crop yield of foxtail millet.