多菌灵在农田土壤中的降解及其影响因子研究

采用实验室模拟方法,研究了微生物、含水量和Cd对土壤中多菌灵降解动态的影响.结果表明,土壤中多菌灵(5.0mg·kg-1和10.0 mg·kg-1)的降解半衰期在灭菌条件下为非灭菌条件下的12.6～13.8倍;复合降解菌群(枯草杆菌、副球菌、黄杆菌和假单胞菌)的加入显著缩短了土壤中多菌灵的降解半衰期(32.1%～37.1%);当土壤含水量由40%田间持水量提高到60%或80%田间持水量,多菌灵降解半衰期缩短46.2%或74.0%;低浓度Cd(5.0 mg·kg-1)的加入显著缩短了土壤中多菌灵的降解半衰期(32.1%～52.4%),而高浓度的Cd(50 mg·kg-1)延长多菌灵的降解半衰期(92.6%～103.0%);对添加复合降解菌群的土壤,低浓度Cd(5.0 mg·kg-1)的加入同样显著缩短了土壤中多菌灵的降解半衰期(34.0%～34.4%),高浓度的Cd(50 mg·kg-1)延长多菌灵的降解半衰期(74.4%～109.4%).研究表明,土著微生物在多菌灵降解过程中发挥重要的作用,多菌灵降解菌群、较高的土壤湿度和低浓度的Cd也促进了土壤中多菌灵的降解.

Degradation of Carbendazim in Paddy Soil and the Influencing Factors

The influences of microorganism, soil moisture and cadmium (Cd) on degradation of carbendazim in paddy soil were investigated with laboratory microcosm experiments. The results showed that the half-life of carbendazim (5.0 mg·kg^-1and 10.0 mg·kg^-1) in sterilized soils was 12.6-13.8 times of those in non-sterilized soils. The half-life of carbendazim was decreased by 32.1%-37.1% when the soils were inoculated with carbendazim-degrading strains. When the soil moisture was increased from 40% to 60% or 80% of water holding capacity, the half life of carbendazim was decreased by 46.2% or 74.0%, respectively. Low level of Cd (5 mg·kg^-1) enhanced the degradation of carbendazim in soils with half-life time decreased by 32.1%-52.4%, but high level of Cd (50 mg·kg^-1) inhibited the degradation of carbendazim in soils with half-life time increased by 92.6%-103.0%. For the soils inoculated with carbendazim-degrading strains, the half life of carbendazim was decreased by 34.0%-34.4% with the addition of low level of Cd (5.0 mg·kg^-1), while the half life time was increased by 74.4%-109.4% with the addition of high level of Cd (50 mg·kg^-1). The results demonstrate that indigenous microorganisms is a critical factor that influences carbendazim degradation in soils, and that carbendazim-degrading strains, high soil moisture and low Cd level enhance the degradation of carbendazim.