棉隆和氯化苦熏蒸对重茬草莓土壤线虫群落及养分含量的影响

Effects of Dazomet and Chloropicrin on the Soil Nematode Communities and Nutrient Content of Replanted Strawberry

以大棚重茬草莓土壤为研究对象,以土壤线虫总丰度、群落组成、生物多样性及生态功能特征、土壤养分等为指标,以冗余分析(RDA)为依据,探究棉隆和氯化苦熏蒸对重茬土壤的正、负面影响,旨在为重茬土壤的科学治理提供参考。结果表明,施用棉隆和氯化苦后,土壤中线虫总量与对照相比分别下降83.24%和85.48%;土壤线虫多样性指数H’和成熟度指数MI无显著变化;土壤有机质、速效磷和速效钾含量均显著降低;p H显著升高。RDA分析结果显示,棉隆和氯化苦与小杆属(Rhabditis)、真滑刃属(Aphelenchus)线虫数量及土壤有机质、速效钾和速效磷含量呈显著负相关。该结果揭示了棉隆和氯化苦施用后除能使有害的真滑刃属线虫数量分别显著下降41.47%和29.77%外,也能使有益的小杆属线虫数量显著下降约10%,还能使土壤养分含量大幅度降低,由此表明棉隆和氯化苦在有效控制土壤中有害线虫种群数量的同时,对有益线虫和土壤养分有明显的负作用。综上,棉隆对有害线虫的抑制作用大于氯化苦,同时使食细菌的真头叶属线虫总丰度增加42.03%,因此认为氯化苦的负面影响更大,在生产中应谨慎使用。

To explore the positive and negative effects of dazomet and chloropicrin on the replanted soil,the abundance of total nematode,community composition,biodiversity and ecological indices,and soil nutrient were used as the main evaluating indices in the greenhouse of strawberry. Based on those above indices and the Redundancy analysis（RDA）,our study will provide references for the replanted soil of scientific management. Our result showed that the total number of nematode in replanted soil declined by 83.24% and 85.48% after applying dazomet and chloropicrin,respectively. But soil diversity index（H＇）and maturity index（MI）had no significant change. The content of soil organic matter,available phosphorus and available potassium was also significantly reduced（68.33% and 50.00%,67.93% and 71.55%,50.36% and 56.20%,respectively）after the application of dazomet and chloropicrin. In addition,the value of p H rose to 7.69 and 7.68,respectively（the value of p H in the control soil was 7.27）. RDA analysis indicated that dazomet and chloropicrin had significantly positive correlations with Rhabditis,Aphelenchus nematodes,soil organic matter,available phosphorus,and available potassium. The result revealed that the number of harmful nematodes of Aphelenchus was reduced by 41.47% and 29.77%,and the number of beneficial nematodes of Rhabditis was significantly dropped about 10% under treatment of dazomet and chloropicrin,respectively. The main reason might be that,the two fumigants could strongly reduce the content of soil nutrient. It was suggested that dazomet and chloropicrin not only could effectively reduce the number of harmful nematodes,but also had negative effect on the beneficial nematodes and soil nutrient. In conclusion,the inhibition effect of dazomet on harmful nematodes was greater than chloropicrin,and the number of Eucephalobus belonging to bacterivores increased by 42.03% with dazomet treatment at the same time. Therefore,the negative effect of chloropicrin was greater and should be used carefully in production.