This study aimed to evaluate the effects of three glyphosate formulations (Roundup Ready® and R. Transorb® - both with isopropylamine salt and Zapp Qi®, formulated as potassium salt), on transgenic soybean. CD 219RR variety soybean plants displaying the CP4Epsps gene, tolerant to glyphosate, were cultivated. At 25 days after emergence (DAE), when plants showed the second trifolium completely expanded (stadiums V2-V3 ), formulations were applied at 2,000 g ha-1 . Plants intoxication was evaluated 15 days after application as well as the number and dry matter of leaflets, number of radicular nodules and foliar content of N, P, K, S, Ca, Mg, Fe, Cu, Zn, and Mn at flowering and grain yield at the end of the cycle. Soil basal respiration rate, microbial biomass carbon and metabolic quotient were evaluated through soil samples collected during soybean flowering. Isopropylamine salt, present in the Roundup Transorb formulation, was more harmful to the soybean plants, also providing a negative effect on the soil microbiota. Roundup Ready formulation, registered as transgenic soybean, should not be applied on this crop at a higher rate, since it could alter the content of some nutrients, such as N, Ca, Mg, Fe and Cu, besides causing intoxication in the plants.
herbicides; selectivity; transgenic soybean; EPSPs inhibitors
