Clomazone Leaching Estimate in Soil Columns Using the Biological Method

Abstract

-The chemical control of weed is a necessary practice in large-scale agriculture. However, when herbicides are used in the wrong way, they can remain into soil for long periods and/or be leached in its profile, and they may even contaminate groundwater. In this research, clomazone leaching in soil samples collected from different Brazilian regions was estimated by biological method. To do so, columns containing soils were used, and samples were collected every 5 cm. After preparing columns and applying a 1,500 g a.i. ha -1 clomazone dose, rain simulation was performed. Sorghum was used in order to detect the herbicide. More than 60% similarity was found for the studied variables; it was chosen to use only data referring to toxicity percentage. Clomazone did not cause reduction in sorghum cultivated in Organosol, thus indicating a strong herbicide sorption in this soil. Increased pH in Oxisol reduced leaching. More rainfall caused increased herbicide leaching in Oxisol (pH 5.1) and Quartzarenic Neosol. The highest leaching occurred in soils with lower pH and lower organic matter content. It is possible to conclude that, in soils with higher organic matter content, clomazone has lower risks of being leached.Keywords: herbicide, mobility in soil, environmental impact. RESUMO -O controle químico das plantas daninhas é prática consolidada na

Tolerance of cassava to postemergence herbicides and determination of residues in the roots

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Leaching of saflufenacil in soils with different organic matter contents

“…Herbicide leaching is directly related to the efficiency of weed control, whose seeds are distributed in subsurface layers of the soil, and to the environmental contamination risk (Pereira et al 2017). Thus, moderate mobility of herbicides in the soil profile is necessary for an efficient control of the weed seed bank (Inoue et al 2015).…”

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