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首页> 外文期刊>International Journal of Environmental Research and Public Health >Degradation of Metalaxyl and Mefenoxam and Effects on the Microbiological Properties of Tropical and Temperate Soils
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Degradation of Metalaxyl and Mefenoxam and Effects on the Microbiological Properties of Tropical and Temperate Soils

机译：甲霜灵和甲霜灵的降解及其对热带和温带土壤微生物特性的影响

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摘要

The degradation of various formulations of the racemic mixture and the enantiomers (including mefenoxam) of metalaxyl in typical soils from Germany and Cameroon in controlled incubation experiments was studied. The kinetics of the degradation or transformation was determined by means of reversed phase HPLC, while the enantiomeric ratios were measured by HPLC with a chiral Whelk O1 column. The dynamics of the quantitative changes in microbiological properties induced by the addition of these fungicides at their recommended field rates were determined in the soils during a 120-day incubation experiment. The degradation followed first-order kinetics (R2≥0.96). Higher metalaxyl acid metabolite concentrations were found in German than in Cameroonian soils. The enantiomers of the fungicide had different degradation rates in both soils, with half-lives ranging from 17 to 38 days. All forms of metalaxyl had lower degradation rates in the Cameroonian soil than in the German soil. The degradation of the R-enantiomer was much faster than the S-enantiomer in the German soil and slower than the S-enantiomer in the Cameroonian soil, suggesting that different microbial populations, which may be using different enzymes, have different degradation preferences. The type of soil significantly influenced the effect of these fungicides on the soil parameters studied. Incorporation of these fungicides resulted in a change in the ecophysiological status of the soil microbial community as expressed by microbial activities. The activity of phosphatases and ?-glucosidase, the mineralization and availability of N and most plant nutrients in soils were stimulated, whereas the activity of dehydrogenase and the availability of NO3-, were generally adversely affected. The soil NH4+, NO3-, and enzymes activities values in general did not correlate with the degradation of metalaxyl in both soils. However, the degradation of formulated and unformulated metalaxyl was positively correlated to the activity of acid phosphatase in the German soil (R2, 0.84 and 0.94 respectively) and in the Cameroonian soil (R2, 0.97 and 0.96 respectively).
机译：在受控温育实验中，研究了德国和喀麦隆典型土壤中消旋混合物的各种配制剂和甲霜灵的对映异构体（包括甲灭灵）的降解。降解或转化的动力学通过反相HPLC测定，而对映体比率通过HPLC用手性Whelk O1柱测量。在120天的温育实验中，确定了在推荐的田间速率下添加这些杀菌剂而引起的微生物特性的定量变化动态。降解遵循一级动力学（R2≥0.96）。在德国发现的甲霜灵代谢产物浓度高于喀麦隆土壤。该杀菌剂的对映异构体在两种土壤中具有不同的降解速率，半衰期为17至38天。喀麦隆土壤中所有形式的甲霜灵降解率均低于德国土壤。在德国土壤中，R对映体的降解比S对映体快得多，而在喀麦隆土壤中则比S对映体慢，这表明可能使用不同酶的不同微生物种群具有不同的降解偏好。土壤类型显着影响了这些杀菌剂对土壤参数的影响。这些杀菌剂的掺入导致微生物活动所表达的土壤微生物群落的生态生理状况发生变化。刺激了磷酸酶和β-葡萄糖苷酶的活性，土壤中氮和大多数植物养分的矿化和有效性，而脱氢酶的活性和NO3-的有效性通常受到不利影响。通常，两种土壤中的NH4 +，NO3-和酶活性值均与甲霜灵的降解无关。但是，配制和未配制甲霜灵的降解与德国土壤（分别为R2、0.84和0.94）和喀麦隆土壤（分别为R2、0.97和0.96）中酸性磷酸酶的活性呈正相关。

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