Effect of pre-emergent graminicide herbicides on germination and early development of native species

Abstract

The occurrence of weeds has been the main obstacle to vegetation recovery in Cerrado areas unduly occupied by agricultural and livestock activities. This study evaluates the effect of different pre-emergent herbicides on the emergence, survival, and early development of seedlings of the native species jatoba ( Hymenaea stigonocarpa ), urucum ( Bixa orellana ), dry flour ( Albizia hasslerii ), and white jurema ( Mimosa interrupta ). The experiment was carried out under greenhouse conditions in a completely randomized experimental design with five replicates, where the treatments were constituted by herbicides: isoxaflutole, applied at the doses of 100, 200, and 300 g ai ha -1 ; pendimethalin, at 500, 1000, and 4000 g ai ha -1 ; and trifluralin, at 600, 1200, and 2400 g ai ha -1 ; in addition to a control treatment, without the application of herbicides. Herbicide phytotoxicity was evaluated at 35 days after emergence for the number of emerged seedlings, number of leaves per seedling, seedling height and diameter, and root and shoot dry weight. With the results obtained, it is possible to affirm that under the conditions of the experiment, all the herbicides and doses used did not affect the emergence and early development of seedlings of species H. stigonocarpa and B. orellana . For species A. hasslerii , the dose of 300 g ai ha -1 of herbicide isoxaflutole was not selective. All doses of the herbicide trifluralin showed selectivity for species M. interrupta .