不同杀线剂对山药土壤线虫群落结构及其理化性质的影响

Effects of different nematicides on soil nematode community and soil properties in yam fields

以苗期山药土壤为研究对象,以土壤线虫群落和土壤理化性质为分析指标,探究6种杀线剂对山药土壤环境的影响,旨在为山药线虫病的科学防治提供参考。结果表明,6种杀线剂对山药土壤含水量、pH、有机质、铵态氮及速效钾含量无显著影响,但均可显著降低土壤速效磷含量。与清水处理(CK)相比,6种杀线剂不仅可大幅提高土壤中有益的食细菌类线虫的相对丰度,也使有害的植物寄生类线虫的相对丰度显著降低,且对拟丽突属Acrobeloides的促生作用以及对根结属Meloidogyne和短体属Pratylenchus的灭杀作用最为明显,尤其是10.5%阿维·噻唑膦颗粒剂和41.7%氟吡菌酰胺悬浮剂,但其也均使有益的食细菌类线虫真头叶属Eucephalobus和丽突属Acrobeles相对丰度显著降低70%以上。对土壤线虫生态指数分析表明,10.5%阿维·噻唑膦颗粒剂和41.7%氟吡菌酰胺悬浮剂处理的土壤线虫丰富度指数(SR)和瓦斯乐斯卡指数(WI)均显著升高,植物寄生线虫指数(PPI)和成熟度指数(MI)无显著变化,但多样性指数(H′)、均匀度指数(J′)和营养类群指数(TD)均显著降低;2.5亿孢子/g厚孢轮枝菌颗粒剂、50亿孢子/g淡紫拟青霉颗粒剂、20%辣根素水剂和10亿孢子/g茶枯抑线生物菌肥(解淀粉芽胞杆菌)不仅可显著降低土壤线虫PPI和PPI/MI、大幅提高SR,对土壤线虫H′、J′和WI和MI影响不大,但50亿孢子/g淡紫拟青霉颗粒剂和10亿孢子/g茶枯抑线生物菌肥(解淀粉芽胞杆菌)处理的TD显著降低。相关性分析结果表明,速效磷含量与土壤线虫数量、属数及植物寄生类线虫相对丰度均呈极显著正相关。综上,6种杀线剂可有效控制植物寄生类线虫种群数量,但2种化学杀线剂还会对土壤有益线虫、土壤养分及线虫群落的多样性和均匀度等产生明显负作用,对土壤环境干扰较大。

In order to provide a reference for scientific control of Chinese yam nematode disease,the effects of six nematicides on the soil nematode community and physical and chemical properties of soil for planting Chinese yam at seedling stage were analysed.The results showed that six kinds of nematicides had no significant effects on soil moisture content,pH value,organic matter,ammonium nitrogen and plant-available potassium,but all treatments could significantly reduce the content of plant-available phosphorus.Compared with the control,the relative abundance of beneficial bacterivores was greatly increased by six kinds of nematicides,meanwhile,the relative abundance of harmful herbivores was significantly decreased.Their growth-promoting effects on Acrobeloides and their killing effects on Pratylenchus and Meloidogyne were the most obvious,especially abamectin·fosthiazate 10.5%GR and fluopyram 41.7%SC.Nevertheless,they also reduced the relative abundance of Eucephalobus and Acrobeles by 70%or more.Analysis of soil nematode ecological indexes showed that SR and WI were significantly increased and there was no significant change in PPI and MI,but the indexes H′,J and TD were significantly decreased after treatment with abamectin·fosthiazate 10.5%GR and fluopyram 41.7%SC.However,the treatments with Verticillium chlamydosporium 25 million spores/g GR,Paecilomyces lilacinus five billion spores/g GR,horseradish 20%AS and one billion spores/g biological bacterial fertilizer for tea curd(Bacillus amyloliquefaciens)not only reduced the indexes of PPI and PPI/MI,increased the index of SR,but also had no effect on the indexes of H′,J′,WI and MI,though the TD index was reduced in the treatments with Paecilomyces lilacinus five billion spores/g GR and one billion spores/g biological bacterial fertilizer for tea curd(Bacillus amyloliquefaciens).Moreover,the results of correlation analysis showed that there was a significant positive correlation between plant-available phosphorus content and soil nematode number,genus number and relative abundance of parasitic nematodes.To sum up,the number of parasitic nematodes could be controlled by the six kinds of nematicides,but the two chemical insecticides also had negative effects on the soil beneficial nematodes,soil nutrients,diversity and evenness of nematode community,which caused greater disturbance to the soil environment than biological nematicides.