Subdoses of 2,4-D Choline Salt on Yield Components in Function of the Soybean Growth Stage

Residues of herbicide tanks may cause damage to sensitive crops. The objective of this study is to evaluate the potential effects of subdoses of the herbicide 2,4-D choline salt on the vegetative and reproductive stages of soybean. The experiment was randomized blocks with a subdivided plot design and four replications. The application times were at V3 and R2 in the main plot. The herbicide 2,4-D choline salt was applied at the subdoses 0, 2.28, 4.56, 9.12, 18.24, 27.36 and 45.60 g a.e. ha-1 in the subplots. Phytotoxicity was evaluated at 3, 7 and 14 days after application (DAT) of treatments, soybean height at 14 and 28 DAT and at ripening, yield components at ripening, and grain yield. The phytotoxicity evaluation of 2,4-D choline salt evidenced that symptoms were only observed up to 14 days after application (DAT) of treatments. The 2,4-D did not affect any of the variables tested. Grain yield was not influenced by application times or subdoses.