异丙甲草胺对烤烟根际土壤微生物和酶活性的影响

为了探明根际微生物数量与除草剂污染之间的关系,研究了异丙甲草胺对烟草植地根际与非根际土壤微生物的种群动态变化、土壤呼吸强度及酶活性的影响。结果表明:根际土壤中微生物数量、土壤呼吸强度和酶活性均高于非根际土壤。根际土壤微生物对异丙甲草胺的敏感程度依次为真菌〉细菌〉放线菌;除过氧化氢酶外,根际土壤脱氢酶、脲酶及磷酸酶的活性与对照土壤均存在显著差异。第60 d,异丙甲草胺在根际土壤中的降解率为80.50%,半衰期为26.82d,比在非根际土壤中的降解速率提高了1.21倍,半衰期缩短了17.76%。

Effect of Metolachlor on the Soil Microorganism and Enzyme Activity of Flue-Cured Tobacco Roots

In order to investigate the relationship between the herbicide contamination and the number of microorganisms in plant rhizosphere soil,the effect of metolachlor on the microbial number,the intensity of soil respiration and the enzyme activity in tobacco rhizosphere and non-rhizosphere soils were studied.The results showed that the number of rhizosphere microorganisms,the soil respiration intensity and the enzyme activity were higher in rhizosphere soil than non-rhizosphere soil.The sensitivity of microorganisms to metolachlor in rhizosphere soil was in the order of fungi ＞ bacteria ＞ actinomycetes.Except for catalase,there were significant differences between activities of dehydrogenase,urease and phosphatase in the rhizosphere soil and in the non-rhizosphere soil.At 60th day,the degradation rate of metolachlor was 80.50％ and its half-life was 26.82 day in rhizosphere soil.The degradation rates of metolachlor in rhizosphere soil were 1.21 times of that in non-rhizosphere soil.The degradation half-life of metolachlor in the rhizosphere soil was 17.76％ shorter than that in the non-rhizosphere soil.