To clarify the impacts of long-term alfalfa plantation on the soil nematode community, soil samples were collected from different alfalfa growing ages (2 a, 9 a, 18 a) in the semi-arid area of Loess Plateau in Central Gansu by Illumina Miseq sequencing technology. The main controlling factors affecting its community change were also explored. The results showed that soil nematode belongs to 2 classes, 7 orders, 16 families and 21 genera. Among them, Chromadorea was the dominant group (44.6%-81.4%), the relative abundance of which decreased with alfalfa growing ages. Paratylenchus, Helicotylenchus, Xiphinema, Pristionchus, Ditylenchus, Panagrolaimus, Longidorus, Aprutides, Isolaimium and Aglenchus were the special nematode species of alfalfa, among which Paratylenchus (54.1%), Helicotylenchus (23.9%) and Xiphinema (21.9%) were the dominant nematodes in 2 a, 9 a and 18 a alfalfa soil respectively. Plant-parasitic nematode was the dominant group in alfalfa soil (31.8%-67.1%), and its relative abundance decreased at first and then increased with alfalfa growing ages. Results of redundancy analysis showed that soil available phosphorus and total nitrogen were the dominant environmental factors affecting community structure of soil nematodes in the region.
为明确长期种植紫花苜蓿对土壤线虫群落演变的影响,以不同种植年限紫花苜蓿为研究对象(2 a、9 a、18 a),并以农田为对照,采用 Illumina MiSeq测序技术研究了陇中黄土高原半干旱区紫花苜蓿土壤线虫群落结构及其多样性,探讨影响其群落变化的主控因子。结果表明: 所获土壤样品线虫种群隶属于2纲7目16科21属,其中,色矛纲为黄绵土优势线虫类群(44.6%～81.4%),相对丰度随苜蓿种植年限延长而降低。针线属、螺旋属、剑线属、Pristionchus、茎属、盆咽属、长针属、艾普鲁斯属、Isolaimium和野外垫刃属为苜蓿地特有线虫,其中,针线属(54.1%)、螺旋属(23.9%)、剑线属(21.9%)分别为2 a、9 a、18 a苜蓿地优势线虫属。紫花苜蓿土壤均以植物寄生线虫为优势类群(31.8%～67.1%),其相对丰度随苜蓿年限延长先降后升。冗余分析显示,土壤速效磷和全氮含量是影响紫花苜蓿土壤线虫群落结构的主导环境因子。.
Keywords: alfalfa; high-throughput sequencing; loessal soil; soil nematodes; trophic groups.