Residual effect of mixture of glyphosate and 2,4-D in winter maize in different soil textures

Efeito residual da mistura glifosato e 2,4-D em milho “safrinha” em solos de diferentes texturas

ABSTRACT

To increase the efficiency in the control of weeds, it is common the use of a mixture of the herbicides glyphosate and 2,4-D in the desiccation. This paper aimed to evaluate the residual effect of these two herbicides on the development of maize plants, in soils of different textures. The experiment was conducted in a greenhouse, in 2015, in a completely randomized design in a 2 x 2 x 7 factorial scheme, corresponding to two soils (Red Yellow Latosol and Quartzarenic Neosol), two herbicide application times (5 and 10 days before maize sowing) and seven doses of herbicides (recommended dose of glyphosate, recommended dose of 2,4-D; mixing the recommended doses of glyphosate and 2,4-D; two, ten and fifty times the recommended doses in admixture; and one control), with 4 replicates. After emergence of maize plants, the following variables were evaluated: phytotoxicity, plant height, chlorophyll a and chlorophyll b, shoot fresh and dry matter and root dry matter. In general, there was lower residual effect on the Red Yellow Latosol at all the doses of the herbicides and in the interval of 10 days between the desiccation and sowing.

Key words:
phytotoxicity; herbicides; Red Yellow Latosol; Quartzarenic Neosol