Avaliação do potencial de lixiviação do herbicida 2,4-D em colunas de solo através de bioensaios com Cucumis sativus

Abstract

The constant expansion of agriculture, especially monoculture, intensified by the development of transgenic seeds, has increased the use of pesticides. In Brazil, the increasing use and release of new pesticides in recent years stands out, with glyphosate and 2,4-D being the most commercialized herbicides in the country. These facts have been generating concerns, especially in relation to the dynamics and persistence of pesticides in soil. In this context, the present study aims to evaluate the leaching potential of the herbicide 2,4-Dichlorophenoxyacetic acid in columns of litholic neosol using Cucumis sativus (cucumber) as bioindicator. For the study the factorial scheme 3 x 4 x 2 was adopted, with irrigation sheets of 0, 40, 80 mm and monitoring depths of 0 - 0.10; 0.10 - 0.20; 0.20 - 0.30 and 0.30 - 0.40 m, in the presence and absence of the herbicide, in triplicates, totalizing 18 columns and 72 experimental plots. The evaluation of the leaching was carried out by means of the analysis of percentage and speed index of emergence of seedlings of the bioindicator. The results show that the emergence of the cucumber was higher in the treatments without the herbicide 2,4-D, independent of the variations of simulated rainfall and depths of the columns. In the presence of the herbicide, the emergence of the bioindicator increased with the increase of the simulated rainfall. It is considered that there is potential for leaching of the herbicide 2,4-D up to 40 cm depth in Litholic Neosols.