Competição de plantas daninhas com a cultura do milho no município de Ijaci, MG

Abstract

The experiment was carried out at the Weed Science Experimental Station, Ijaci, MG, Brasil, in a Yellow-Red Latosol, using the corn hybrid Cargil 435 in the growing season of 1998/99 with the objective of defining the critical period of competition of weeds with corn. The interference periods of the weeds were based on phonological stages of the crop. The weeding of the plots was performed by hand hoeing as following: hoeing from the 2nd, 3rd, 4th, 5th, 6th, and 7th leaf up to the end of the cycle or up to tasseling stage. Three more treatments were included: weeding from tasseling stage up to the end of the crop cycle, hoed check during the entire cycle, and unhoed check. No weeding corn caused 14%, 22%, and 22% reduction on culm diameter, ear weight, and grain weight, respectively when compared with hoed check. Grain weight did not alter when hoeing was done until tasseling stage in comparison with the hoed check during the entire cycle. The interference of the weed was augmented only when hoeing was done from the sixth leaf, with the ligule already visible, considering the cultivar used.