Role of pH on Metribuzin Dissipation in Field Soils

Ladlie, James S.; Meggitt, W. F.; Penner, Donald

doi:10.1017/s004317450006656x

Cited by 35 publications

(25 citation statements)

References 14 publications

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“…Specifically, the amine group of the herbicide is eliminated upon reaction with alcohols and carboxylic groups of organic matter 35. On the other hand, positive correlations were observed between metribuzin dissipation and soil properties such as pH, organic carbon content and bioactivity 36, 37. These parameters are also correlated with each other, as an increase in the organic carbon content usually parallels soil bioactivity.…”

Section: Resultsmentioning

confidence: 99%

Reduced metribuzin pollution with phosphatidylcholine–clay formulations

Undabeytia

Recio

Maqueda

et al. 2010

Pest Management Science

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Section: Resultsmentioning

confidence: 99%

Reduced metribuzin pollution with phosphatidylcholine–clay formulations

Undabeytia

Recio

Maqueda

et al. 2010

Pest Management Science

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“…In another study on metribuzin, a negative correlation between sorption and soil pH was demonstrated. At pH 6.7 the sorption was about twice as the sorption at pH 4.6 (Ladlie et al, 1976). However, the sensitivity to pH may not be equal for metribuzin and the metabolites.…”

Section: Resultsmentioning

confidence: 99%

“…Other unidentified metabolites are detected in experiments using 14 C‐labeled metribuzin (Moorman and Harper, 1989; Locke et al, 1994). Total degradation of metribuzin to inorganic species (mineralization) is usually below 10% of the metribuzin applied (Ladlie et al, 1976; Locke et al, 1994; Mallawatantri et al, 1996) and the highest result measured is 20% within 90 d (Moorman and Harper, 1989). Thus, stable metabolites may accumulate in the soil.…”

mentioning

confidence: 99%

Degradation and Sorption of Metribuzin and Primary Metabolites in a Sandy Soil

2004

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Leaching to the ground water of metabolites from the herbicide metribuzin [4-amino-6-(1,1-dimethylethyl)-3-(methylthio)-1,2,4-triazin-5-one] has been measured in a Danish field experiment in concentrations exceeding the European Union threshold limit for pesticides at 0.1 microg/L. In the present work, degradation and sorption of metribuzin and the metabolites desamino-metribuzin (DA), diketo-metribuzin (DK), and desamino-diketo-metribuzin (DADK) were studied in a Danish sandy loam topsoil and subsoil from the field in question, using accelerated solvent extraction and liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. Fast dissipation of metribuzin and the metabolites was observed in the topsoil, with 50% disappearance within 30 to 40 d. A two-compartment model described degradation of metribuzin and DA, whereas that of DADK could be described using first-order kinetics. Part of the dissipation was probably due to incorporation into soil organic matter. Degradation in subsoil occurred very slowly, with extrapolated half-lives of more than one year. Sorption in the topsoil followed the order DA > metribuzin > DK > DADK. Subsoil sorption was considerably lower, and was hardly measurable for metribuzin and DK. Abiotic degradation was considerably higher in the topsoil than the subsoil, especially concerning the de-amination step, indicating that organic matter may be related to the degradation process. The present results confirm observations of metribuzin and transformation product leaching made in the field experiment and demonstrate the need for knowledge on primary metabolites when assessing the risk for pesticide leaching.

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“…Applied either pre‐emergence or early post‐emergence, metribuzin is very effective against annual grasses and numerous broad‐leaved weeds. As the soil is a complex system, degradation and dissipation of herbicides (including metribuzin) may be influenced by many factors, such as pH (Ladlie et al. , 1976a,b), temperature, moisture (Zimdahl et al.…”

Section: Introductionmentioning

confidence: 99%

Retention and degradation of metribuzin in sandy loam and clay soils of Lebanon

et al. 2003

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Summary The retention and degradation of metribuzin herbicide were studied under two environmental conditions. Field studies were carried out on two soils, a sandy loam soil (soil A) and a clay soil (soil B). Metribuzin was applied with a jet sprayer at 1060 g a.i. ha−1 and 1960 g a.i. ha−1 on soils A and B respectively. Reconstituted soil columns were used to study the herbicide movement and metabolism in the two soils. Analyses of metribuzin and its metabolites were carried out using standardized methods. The results indicated a very weak capacity of adsorption of metribuzin in the two soils, and the weak adsorbed fraction is easily desorbed. Degradation and mobility of metribuzin in the field and laboratory soil columns were very intense and rapid. Soil A favoured reductive deamination whereas soil B favoured oxidative desulphuration and the respective metabolites deaminometribuzin and diketometribuzin yield the same product deaminodiketometribuzin. Both leaching by rainfall and degradation were important in the disappearance of metribuzin from the soils.

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Role of pH on Metribuzin Dissipation in Field Soils

Cited by 35 publications

References 14 publications

Reduced metribuzin pollution with phosphatidylcholine–clay formulations

Reduced metribuzin pollution with phosphatidylcholine–clay formulations

Degradation and Sorption of Metribuzin and Primary Metabolites in a Sandy Soil

Retention and degradation of metribuzin in sandy loam and clay soils of Lebanon

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