Carryover of [imazapic + imazapyr] on differents crops systems in lowland areas with ALS tolerant rice

Abstract

Clearfield ® technology is an important tool for chemical weed management in rice fields, however, carryover of these herbicides is still a concern for crops in succession. In this study, we aimed to evaluate the impact of the herbicide Kifix ® (imazapic + imazapyr) associated with Clearfield ® technology of rice crops on ryegrass in succession, as well as on non-Clearfield ® rice and soybean grown in rotation, in addition to the control potential of jointvetch (Aeschynomene rudis and A. denticulata) from 2016 to 2018. The experiments comprised the application of Kifix ® to Clearfield ® rice grown in the first experimental year, evaluating its impact (1 st summer) on ryegrass grown the following winter, as well as on soybean, rice and non-Clearfield ® rice grown the following summer (2 nd summer). The results reported reductions in jointvetch density and infestation as Kifix ® doses increased; as well as mild damage from Kifix ® residues on ryegrass sown in succession to Clearfield ® rice, as well as on non-Clearfield ® rice and soybean in rotation to Clearfield ® rice. In addition, the possibility of residue accumulation of Kifix ® in the soil after repeated applications should be verified in further studies.