摘要:为探索沼液抑制根结线虫的效果，本研究通过盆栽试验，以番茄为试供作物，对比了种植前沼液淹没土壤（BSS）、种植期间浇灌沼液（BS）和加热（HE）3种方法对根结线虫的防控效果。结果表明，与不采取任何措施的对照（CK）处理相比，BSS处理抑制根结线虫效果最为明显，防效高达97.1%，根结指数分别比HE和BS处理降低96.9%和92.9%。HE处理尽管在处理土壤后显著降低了根结线虫数量，但在最后破坏性取样时（结束试验）出现反弹，根结线虫数量甚至高于CK处理。对于土壤线虫群落，CK处理中以植食性线虫为主（81.8%）；两个沼液处理中食细菌线虫占优势（平均78.3%），且其中的杂食捕食性线虫在土壤前处理后消失，在试验结束时又重新出现，但所占比例依然非常低。沼液淹水方式的高效防控效果揭示了利用沼液防控根结线虫的关键期在于线虫入侵到植物根部之前的幼虫期。然而，在盆栽系统中，沼液淹水的方式也对作物生长表现出了一定的抑制趋势。高量沼液施用防控病害的同时引发的植物毒害作用以及环境污染风险，需要进一步开展田间研究。
关键词:根结线虫/
沼液/
淹水/
土壤线虫群落/
土壤食物网
Abstract:Root-knot nematodes (RKN, Meloidogyne spp.) cause soil-borne diseases in food crops, and can lead to a huge crop damage worldwide. It has been demonstrated that application of biogas slurry during planting is an effective method to control diseases caused by RKN. We explored the inhibition effect of biogas slurry on RKN by a soil flooding method to provide scientific basis for a new idea to prevent and control soil-borne diseases. A pot experiment was conducted using soil infected with RKN from a vegetable greenhouse. Four treatments were set: 1) biogas slurry was routinely applied to soil three times during the planting period (BS), with an application rate of NH4+ 50 mg·kg-1; 2) soil was pretreated by flooding with 70% biogas slurry twice before planting (BSS); 3) soil was covered with mulching films and heated to 45 ℃ (HE) to simulate a conventional smothering process and, 4) soil was untreated (CK). The most obvious inhibition of RKN was BSS treatment, with a control effect of 97.1%. The root-knot index in BSS treatment decreased by 96.9% and 92.9%, respectively, compared with that of HE and BS. However, this method showed a small trend of inhibiting crop growth. Although HE significantly reduced the number of RKN compared with CK, the RKN number rebounded at the later stage (60 d after treatment), and even was higher than that of CK. Taken together, the proportion of herbivores nematode was the highest in CK (mean 81.8%), while bacterivores dominated in the two biogas slurry treatments, BS and BSS (mean 78.3%). Omnivores and carnivores nematode disappeared in soil flooded with biogas slurry, although they reappeared at the destructive sampling period, the relative abundance was still very low. In the pot system, soil flooding with biogas slurry before planting significantly improved the inhibition effect on RKN compared with the application of biogas slurry during planting. This result revealed that the critical period of using biogas slurry to prevent and control RKN is at the larval stage: that is, before nematodes invade plant roots. Further studies are needed under field conditions to study the toxic effects of biogas slurry flooding in plants, and the potential risk of environmental pollution.
Key words:Root-knot nematode/
Biogas slurry/
Soil flooding/
Soil nematode community/
Soil food web
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