Information is contradictory as to the time Brachiaria brizantha seeds can remain mixed with the NPK fertilizer without causing poorly formed stands. Therefore, the objective of this research was to study the effect of contact times of NPK granular fertilizer (04-14-08 rate) with seeds of this forage on physiological quality (germination and vigor). A completely randomized design with four replicates was employed. An analysis of variance was conducted and the means were compared by Tukey test at 5%. Polynomial regression analyses were also performed, and equations were fitted. A significant effect was observed in all variables. The water content and electric conductivity of seeds increased as contact time with the fertilizer increased, while decreases were observed in germination percentage, first count, emergence, and emergence velocity index. A linear behavior was observed for the variables. Consequently, seeds can be mixed with NPK fertilizer as long as seeding is performed immediately afterwards, thus reducing damages to the physiological quality of the forage seeds (germination and vigor). In practice, it is recommended that B. brizantha seeds should be mixed with NPK at quantities that can be seeded within 12 hours from mixing, at most.
granular chemical fertilizer; contact time; germination, vigor; physiological quality
