油菜不同还田量对新疆盐碱土壤线虫群落的影响

油菜适应性广、抗逆性强，作绿肥还田可以改善土壤环境，有利于土壤生态系统的可持续发展。试验设置油菜不同还田量处理(CK:不还田；T1:21 000 kg·hm^-2;T2:42 000 kg·hm^-2;T3:84 000 kg·hm^-2),利用高通量测序技术研究土壤线虫群落对油菜还田的响应。结果表明：(1)相较于CK,油菜不同还田量能够使土壤pH降低4.19%～6.59%,土壤总盐含量降低4.07%～6.86%,土壤容重降低9.68%～12.90%;T2处理土壤有机质含量较CK增加了27.42%,T3处理土壤碱解氮和速效钾含量较CK增加了35.46%和11.12%;(2)土壤样品中共检测出线虫3纲3目13科19属24种，各处理优势营养类群均为食细菌类线虫；随着油菜还田量的增加，食细菌类线虫与捕食杂食类线虫相对丰度逐渐降低，而食真菌类线虫与植物寄生类线虫的相对丰度逐渐升高；与CK相比，油菜还田后土壤线虫丰富度指数降低，多样性指数升高，富集指数EI与结构指数SI降低；(3)土壤有机质和速效钾是影响线虫群落结构变化的主要环境因子。...

Effects of different returning amount of rape on nematode community in saline alkali soil in Xinjiang

Rape has wide adaptability and strong stress resistance. Returning green fertilizer to the field can improve the soil environment and is conducive to the sustainable development of soil ecosystem. In this study, rape was treated with different returning amounts (CK: no returning; T1: 21 000 kg·hm^-2; T2: 42 000 kg·hm^-2; T3: 84 000 kg·hm^-2). High throughput sequencing was used to study the response of soil nematode community to rape returning. The results showed that: (1) Compared with CK, different returning amounts reduced soil pH by 4.19%~6.59%, total soil salt by 4.07%~6.86%, and soil bulk density by 9.68%~12.90%. The content of soil organic matter in T2 treatment increased by 27.42% compared with CK, and the contents of alkali hydrolysable nitrogen and available potassium in T3 treatment increased by 35.46% and 11.12% compared with CK. (2) 24 species, 19 genera, 13 families, 3 classes, 3 orders of nematoda were detected from all soil samples. The dominant trophic groups of each treatment were bacterial eating nematodes. With the increase of returning amount, the relative abundance of bacteria|eating nematodes and predatory omnivorous nematodes gradually decreased, while the relative abundances of fungal|eating nematodes and plant|parasitic nematodes gradually increased. Compared with CK, the soil nematode richness index decreased, the diversity index increased, and the enrichment index EI and structure index SI decreased. (3) Soil organic matter and available potassium were the main soil environmental factors affecting the change of nematode community structure. In conclusion, rape returning improved soil structure, enhanced soil comprehensive fertility, increased the diversity and complexity of nematode community, and made the ecosystem tend to be stable. The amount of rape returning should be 84 000 kg·hm^-2.