甲基对硫磷对红壤地区土壤微生物数量的影响

EFFECTS OF METHYL PARATHION ON SOIL MICROBIAL POPULATIONS IN RED SOIL REGION

有机P农药是我国最重要一种农药类型,在农业生产上使用广泛。采用室内模拟方法,研究了甲基对硫磷对红壤地区不同类群土壤微生物数量的影响。研究结果表明,甲基对硫磷对土壤微生物数量的影响随甲基对硫磷添加的浓度、微生物类群和培养时间的不同而变化。添加100 mg/L和500 mg/L浓度甲基对硫磷能明显增加土壤细菌的数量,细菌数量的最大值出现在第10天左右;低浓度甲基对硫磷对土壤微生物数量影响不大。平板混合菌体培养实验证明,甲基对硫磷通过抑制或者杀灭某些种类土壤细菌,从而大大促进土壤生态系统中部分种类细菌数量的增殖。

Organic phosphorus pesticide is the most important type of pesticides in China, and widely used in agriculture. In this paper, effects and mechanism of Methyl parathion on soil microbial populations in red soil region are studied. The results show that the effects of Methyl parathion on soil microbial populations changed with Methyl parathion concentration, microbial distribution and cultivating time. The total counts of soil bacteria were greatly increased as a result of addition of 100 mg/L and 500 mg/L Methyl parathion to soil suspension, and the maximum counts of bacteria were observed on day 10. While 10 mg/L Methyl parathion was added to soil suspension, the soil microbial populations changed slightly. The mixed bacteria on Petri dishes were washed in to tubes, then 0 mg/L and 500 mg/L Methyl parathion was added respectively, and the influence of Methyl parathion on mixed bacteria growth was investigated. This experiment revealed that cell concentration of mixed bacteria was affected by Methyl parathion, and the origins of mixed bacteria selected by Methyl parathion determined the cell concentrations. It is suggested that Methyl parathion increases bacteria populations in the soil ecosystem by way of restraining or killing some strains of soil bacteria.