HERBICIDES ASSOCIATIONS FOR BURNDOWN PRIOR SOYBEAN SOWING

Abstract

In the soybean crop, weed resistant to glyphosate, such as horseweed and ryegrass, are
difficult to control, making it necessary to associate other herbicides with different
mechanisms of action. The objective of the study was to evaluate the influence of the
association of herbicides to control glyphosate resistant weed in the soybean pre-planting
desiccation and crop development and yield. The experiment was carried out in the
2018/2019 crop year, in an agricultural area that spent the winter fallow. The experiment
used a randomized block design with eight replications. The experimental treatments
consisted of three different combinations of herbicides applied in pre-planting of the
soybean crop, 40 days before sowing the cultivar TMG 7062 IPRO: glyphosate +
sethoxydim, glyphosate + 2,4-D + sethoxydim and glyphosate + 2,4-D. The associations of
glyphosate with the herbicides 2,4-D and setoxidim in the pre-sowing desiccation of
soybean provided greater control of broad and narrow leaf weeds, respectively. No
synergism or antagonism effects were found in the herbicide associations, only addition
effect improving the control. The different pre-planting desiccation treatments provided no
effect on the Falker chlorophyll index, nor on the grain yield and its components.