The objective of this work was to evaluate the effects of cover nitrogen fertilization on selectivity of post-emergence applied herbicides in corn (Zea mays). Thus, two experiments were conducted: in one of them, urea (67.5 kg ha-1) was used as nitrogen source and in the other ammonium sulfate (62 kg N ha-1) was used. The treatments consisted of a factorial combination of four levels of herbicide: mesotrione (144 g ha-1 ) + atrazine (1,500 g ha-1 ), foransulfuron + iodosulfuron (45 + 3 g ha-1), nicosulfuron (20 g ha-1 ) + atrazine (1,500 g ha¹ ) and handweeded checks; and four levels fertilization timing: 7, 3 and 0 days before and 7 days after herbicide application (DAA), totalizing 16 treatments. Phytotoxicity at 7, 14, 21 and 28 DAA, height at flowering, mass of 1,000 grains and crop yield were evaluated. No significant interaction was detected between the herbicides and the nitrogen sources used for the variables evaluated. Although phytotoxicity effects were observed, no significant differences were found for plant height, mass of 1,000 grains or crop yield.
management; nitrogen; sulfonylurea; mesotrione; phytotoxicity
