竹林土壤中甲基对硫磷降解菌的降解效果及其与土壤物理特性的关系

Degradation effectiveness of parathion-methyl degrading bacteria in bamboo soil and relationships with its physical characteristics

采用实验室控制试验研究了甲基对硫磷降解菌在竹林土壤生态系统中的降解效果及其与土壤物理特性的关系。试验结果表明,邻单胞菌(DLL-1)具有高效性,甲基对硫磷初始浓度为15 mg/kg干土,第5 d竹林土壤上、中和下层的降解率分别为88.6%、85.9%和79.2%,相应的半衰期为2.5、2.84与3.79 d。甲基对硫磷在土壤中的不同粒径范围吸附情况是不同的,从而影响DLL-1菌的降解效果,表现为土壤中粘粒含量与降解率呈显著正相关。孔隙度也是影响降解效果的一个因素,上中下3层的降解率随着孔隙度的减小而降低。

Biodegradation of parathion-methyl with DLL-1 （Pseudomonas sp. ） in soil of a bamboo forest and the relationship with physical properties of the soil were investigated under the laboratory conditions. DLL-1 was highly effective in degrading parathion-methyl, and the degradation rate of parathion-methyl after a 5-day treatment was up to 88.6% , 85.9% and 79.2% , respectively. Correspondingly, the half-life of the pesticide was 2.5,2.84 and 3.79 days. The adsorption of parathion-methyl on the soil was related to soil particle diameters, which strongly affected the degrading efficiency. There was a significant positive correlation between clay content and degradation rate. Soil porosity also affected the degradation rate of parathion-methyl, namely, the degradation rate increased with an increase in soil porosity.