18. Biological efficacy of herbicide systems tested over local maize hybrid KN 509 and influence over it’s productivity

In 2016 and 2017 was inducted field experiment by “Block method” at the Maize Research Institute, Knezha, R Bulgaria. The subject of the research was the local hybrid Kn 509 (FAO 500 group of maturity), grown under non-irrigating conditions, after the wheat crop. 7 herbicide systems have been obtained only in vegetation period. The most efficient herbicide combinations are: Calaris Pro (2 l/ha) + Milagro (0.2 kg/dka) with 87% killed weeds, Elumis (2 l/ha) + Pik (0.02 kg/ha) with 84% killed weeds and self-introduced leaf herbicide Principal +“ at a dose 0.4 kg/ha with 86% destroyed weeds. Biological efficacy of the herbicides is linked with grain yield.The highest grain yield of maize (6060 t/ha) has been obtained from the self-introduced variant with Principal + at a dose of 0.4 kg/ha.