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Metalaxyl mobility in acid soils: evaluation using different methods
Fernández-Calviño, D.; Bermúdez-Couso, A.; Nóvoa-Muñoz, J. C. & Arias-Estévez, M.
Abstract
In the present work, different methods were
tested to evaluate the adsorption and desorption of metalaxyl
in two acid soils with different organic carbon and
clay contents. The three methods (batch, stirred flow
chamber and column) that were examined produced similar
findings when the two soils were compared: (a) the metalaxyl
adsorption capacity was higher in the soil with
higher organic matter and clay content, and (b) the soil
with the lower organic matter and clay contents provided
higher adsorption rate constants. In the two soils tested, the
metalaxyl adsorbed in the soil was highly reversible. When
only one soil was considered, the different methods yielded
different results. The metalaxyl adsorption and its rate were
higher with the stirred flow chamber than in the column
experiments, and in the column experiments, the total
metalaxyl adsorption and the rate of adsorption were higher
than in the batch experiments. The percentages of
metalaxyl desorbed from the soil were similar in the stirred
flow chamber and column experiments, but in the batch
experiments, the percentages were significantly lower. In
the stirred flow chamber experiments, the desorption processes
were faster than the adsorption processes, while in
the column experiments, the adsorption and desorption
processes exhibited similar rates.
Keywords
Metalaxyl; Adsorption–desorption; Batch; Stirred flow chamber; Column; Soil
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