Épocas de aplicação de ureia e ureia revestida relacionada à aplicação de nicosulfuron em híbridos de milho

Abstract

Nicosulfuron application near to nitrogen fertilizer might cause injuries and affect final corn grain yield, but recently researchers showed none effect on grain yield using fertilizers with fast nitrogen release. A study relating to timing of application of fertilizers with slow nitrogen release and nicosulfuron is essential. Therefore, this study aimed to evaluate the association of nicosulfuron and urea or coated urea timing of application in corn hybrids of different genetic basis. Field studies were conducted in an experimental field at Universidade Federal de Goiás, campus Jataí. The experimental design was randomized complete block in a factorial arrangement with two control treatments, which were the urea and coated urea applied at V4 without herbicide and replicated three times. Used two nitrogen source (urea and coated urea) in different timing of application (four (-4), two (-2) days before, at the same day, two (2) and four (4) days after the nicosulfuron application). The hybrid P 3646 was the most sensitive while MG 30A37, DOW 2B610 and DKB 310 were the least sensitive, showing a negative percentage of development delaying. The hybrids P 3646 and SYN 73413 were the only ones that all nicosulfuron treatments had lower steam diameter than control treatments. The cob and seed length, 500 grain’s weight and row per ear were not much influenced by the interaction nicosulfuron and nitrogen, but most of the hybrids showed better results when coated urea was associated to nicosulfuron. Finally, the productivity was most influenced by the timing of urea or coated urea application rather than interaction of the factors. Thus, the grain yield from the hybrids was not significantly affected by the application of nicosulfuron near to nitrogen fertilizers.