高浓度2,4-D是一种苯氧羧酸类除草剂,被广泛应用于控制谷类和牧草中的阔叶杂草。研究以2份麦田黑土为材料,以2,4-D田间用量的10倍和100倍分别处理,在56 d的监测时间内研究土壤微生物对高浓度2,4-D的响应及降解特性。结果表明,在田间使用剂量的10倍即50 mg kg-1处理时,无论有无2,4-D施用历史,土壤中的微生物都可以适应2,4-D并产生降解反应,但有施用历史的土壤中2,4-D的降解半衰期更短。而田间使用剂量的100倍即500 mg kg-1处理时对土壤微生物有强烈的抑制作用。 High concentration 2,4-D, a phenoxycarboxylic acid herbicide, is widely used to control broad-leaved weeds in cereals and pasture. In this study, two wheat fields were treated with 10-fold and 100-fold doses of 2,4-D, respectively. The response to soil 2,4-D and the degradation of soil microorganisms were studied during the 56-day monitoring period. The results showed that the microorganisms in the soil were able to adapt to 2,4-D and produce a degradation reaction regardless of the presence or absence of 2,4-D administration at a dose of 10-fold, 50 mg kg-1, The degradation half-life of 2,4-D in historic soils was shorter. In the field, the amount of 100 times that 500 mg kg-1 treatment of soil microorganisms have a strong inhibitory effect.