Selection of tolerant species to imazapic for potential use in phytoremediation

Using herbicides results in environmental impacts and it is necessary employing sustainable technologies to reduce its residues in the soil. Imazapic, used in the sugarcane cultivation, shows persistence and mobility in the environment. This study aimed to identify plant species tolerant to imazapic with the potential for phytoremediation of soils with residues of this herbicide. The tests were conducted under greenhouse conditions involving the species Urochloa decumbens, Urochloa brizantha, Urochloa ruziziensis, Mucuna pruriens, Panicum maximum, Sorghum bicolor, Crotalaria ochroleuca, Crotalaria spectabilis and Canavalia ensiformis grown in two soils: one of sandy clay loam texture and the other of sandy clay texture. In each test, five imazapic doses (0.00, 58.33, 87.50, 175.00 and 350.00 g ha-1) were applied in pre-emergence. In all tests, the treatments were in randomized blocks with four replicates each. The soil of sandy clay loam texture with low organic carbon content decreased the tolerance of the evaluated species to imazapic due to its higher bioavailability. The species Canavalia ensiformis, Mucuna pruriens and Urochloa brizantha demonstrated lower phytotoxicity and higher dry matter production in the presence of the highest imazapic doses in the soil. The tolerance from these species can be considered as an indicator of their phytoremediation potential of soils contaminated with imazapic.