Applications of pre-emergence herbicides are designed to obtain residual activity at the beginning of the crop cycle and suppress the new flow of weeds. However, this can affect subsequent crops depending on the variety and persistence of the herbicides in soil. Thus, this study aimed to evaluate the herbicides' carry-over effect on subsequent cultures of soybean RR, beans (IAPAR81) and maize, provided by trifluralin and S-metolachlor, applied in pre-emergence 120days before crop sowing. The trifluralin doses (kgha-1) used were 0.00, 0.27, 0.54, 1.08, 2.16, and 4.32, and the S-metolachlor doses (kgha-1) were 0.00; 0.36, 0.72, 1.44, 2.88, and 5.76. For trifluralin, only a reduction in the chlorophyll content (mg cm-2) and in the amount of dry matter produced by the bean plants (IAPAR 81) was observed at 28 days after sowing (DAS), whereas in soybean RR plants (CD214) only a reduction in the amount of dry matter was observed. S-metolachlor not only caused a reduction in height and injuries in the bean plants at 7 and 14DAS, but also reduced the dry matter levels. In soybean, S-metolachlor affected the amount of dry matter produced and caused mild to moderate phytotoxicity. These results show that, depending on the dose used, both S-metolachlor and trifluralin may cause negative effects on soybean RR (CD214) and beans (IAPAR81), applied in pre-emergence at 120days before crop sowing. However, these herbicides did not affect the development of the corn plants.
phytotoxicity; persistence; cotton
