ASSOCIATION OF PESTICIDES WITH SOYBEAN LEAF MICRONUTRIENTS CONTENTS AND SEEDS YIELD AND PHYSIOLOGIC QUALITY

Abstract

Glyphosate effects on leaf micronutrients contents of transgenic soybean have been widely reported, however, little is known about these effects associated with other pesticides. The objective of this study was to evaluate the physiologic quality and yield of soybean seeds, as well as leaf micronutrients contents, according to weed control methods. Ten RBD treatments were arranged in a split-plot scheme with four replications. The application or non-application of endosulphan + tebuconazole was evaluated in the plots, while the weeds control methods were assessed in the subplots (weeded control; non-weeded control; single application of glyphosate (1,080 g ha^-1) and fomesafen + fluazifop-?-butil (180 + 225 g ha^-1), both at 15 DAE; and sequential application of glyphosate (1,080 g ha^-1) at 15, 30, and 45 DAE). After harvesting, the soybean seeds were sampled, in order to evaluate their germination, vigor, and yield. Copper and manganese contents were only influenced by the sequential application of glyphosate, associated with endosulphan + tebuconazole. The cold test germination was reduced in seeds of plants treated with fomesafen + fluazifop-p-butil associated with endosulphan + tebuconazole. Among the treatments without endosulphan + tebuconazole, the sequential application of glyphosate promoted the highest 100-seeds weight, as well as, when associated with endosulphan + tebuconazole, reduced the leaf concentrations of Cu and Mn, however, it improved seeds germination and showed no effects on seeds vigor, when compared with the weeded soybean.