甲拌磷残留对加工番茄根际与非根际微生物活性的影响

Effects of Phorate Residue on Microbial Activities in Processing Tomato Rhizophere and Bulk Soil

为明确甲拌磷在农田环境中的生态效应,通过盆栽模拟试验研究了0、2、8、20、50mg/kg 5个甲拌磷浓度对加工番茄根际与非根际土壤可培养细菌、真菌、放线菌以及土壤脲酶和碱性磷酸酶活性的影响。结果表明：施入甲拌磷对土壤中的真菌、放线菌有抑制作用,但很快恢复到正常水平,对细菌有明显的抑制作用,4个浓度处理对根际土壤细菌的平均抑制率分别为10.4%、12.7%、19.5%、16.9%,对非根际土壤细菌的平均抑制率分别为11.6%、18.4%、26.2%、27.5%。根际土壤细菌数量大于非根际土壤,细菌根际效应R/B为1.51~2.59,真菌、放线菌根际效应不明显。2mg/kg和8mg/kg甲拌磷处理对番茄非根际土壤脲酶有抑制作用,而20mg/kg和50mg/kg甲拌磷对番茄非根际土壤脲酶有刺激作用。甲拌磷对番茄根际与非根际土壤碱性磷酸酶均有一定刺激作用。

To accertain the ecological effect of phorate in the cropland condition,the influence of phorate on the quantities of processing tomato rhizophere and bulk soil bacteria,fungi,actinomyces and soil urease,alkaline phosphatase activities under the pot culture experiment was studied in this paper.Phorate was added to soil at dosages of 0,2,8,20,50 mg/kg,respectively.The results showed that phorate decreased the number of fungi and actinomyces and then recovered quickly to the levels of ck.Bacteria comminity was inhibited significantly after the application of phorate and the inhibiting effect was more obvious with the increase of concentration of the phorate.Average inhibiting rates of bacteria in rhizophere and bulk soil were 10.4%,12.7%,19.5%,16.9% and 11.6%,8.4%,26.2%,27.5%,respectively.The number of bacteria in rhizosphere soil was larger than that in bulk soil,and the R/B was between 1.51~2.59.The number of fungi and actinomycetes was relatively stable as phorate was applied,and the rhizosphere effect was not significant in this study.When phorate at concentration of 2,8 mg/kg phorate,the activities of soil urease were inhibited in tomato bulk soil,while at the concentration of 20,50 mg/kg,the activities of soil urease were stimulated in tomato bulk soil.Phorate application remarkably stimulated the activities of soil alkaline phosphatase both in rhizophere and bulk soil.