[目的]研究不同施用量下,精异丙甲草胺对甜菜田不同土壤深度中各类主要微生物种群的变化,分析其对土壤主要微生物类群的影响作用.为精异丙甲草胺对土壤生态系统的深入研究和田间科学合理的施用奠定基础.[方法]采用固体平板计数法,研究土壤中的细菌、真菌和放线菌进行变化趋势.[结果]精异丙甲草胺对土壤中的细菌主要表现为抑制作用,且抑制作用与浓度呈正比,最大抑制率随着土壤深度而降低,在0～5、5～10和10～15 cm的最大抑制率分别是43.25％、32.57％、27.54％.精异丙甲草胺对土壤中真菌数量的影响主要表现为先抑制后促进的作用.最大激活率随土壤深度而降低,在0～5、5～10和10～15 cm最大激活率分别是64.10％、45.07％、27.78％.精异丙甲草胺对土壤中放线菌的影响大致为抑制-激活-恢复,最高抑制率在0～5、5～10和10～15 cm分别是62.85％、55.29％、35.40％.[结论]低施用量的抑制作用和激活作用都不如高施用量表现的明显,且放线菌总数随着时间的变化呈现递减的趋势.%[Objective] This project aims to study the effects of S-metolachlor on the main microbial populations in different soil depths in sugar beet field and clarify its effect on soil main microbial groups.[Method][Result]S-metolachlor mainly inhibited the bacteria in soil, and the inhibition was directly proportional to the concentration, and the maximum inhibition rate decreased with the depth of the soil. The maximum inhibitory rates of 0-5, 5-10 and 10-15 cm soil were 43.25％, 32.57％ and 27.54％, respectively. The effect of S-metolachlor on the number of fungi in soil was inhibited first and then promoted. The maximum activation rate decreased with soil depth. The maximum activation rates of 0-5, 5-10 and 10-15 cm soil were 64.10％, 45.07％ and 27.78％ respectively. The inhibitory and activation effects of low application rate were not as obvious as those of high application rate. The effect of S-metolachlor on actinomycetes in soil was approximately inhibition, activation and recovery. The highest inhibition rates were 62.85％, 55.29％ and 35.40％ respectively in 0-5, 5-10 and 10-15 cm soil, and the total number of actinomycetes showed a decreasing trend over time.[Conclusion]The study has established the foundation for further study on soil ecosystem and scientific and rational application of S-metolachlor in fields.
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