Period of Weed Interference in Bean With Nitrogen Fertilizer

The competition between weeds and bean plants, mainly by nutrients of the environment, is one of the main causes of low crop yield. Therefore, the objective of this study is to evaluate the effects of nitrogen fertilization on the extension of the period prior to interference (PPI) in common beans, cultivar TAA GOL. Sowing was performed in conventional system. The treatments were divided into two groups: cover nitrogen fertilization (200 kg urea ha-1) and no cover fertilization. Within each area, we established periods of cohabitation of the crop with weeds from the emergence up to seven times of its life cycle (0-10, 0-20, 0-30, 0-40, 0-50, 0-60, 0-70 days) and a control. The experiment design was randomized blocks with three replicates. Digitaria spp. presented a greater relative importance in both areas, followed by Eleusine indica. The period prior to weed interference (PPI) in the area with nitrogen fertilization occurred up to 46 days after emergence (DAE), and only up to 3 DAE for the area without cover fertilization. There was a 30% decrease in bean productivity by comparing the area with nitrogen fertilization (2,004.79 kg ha-1) and the area without nitrogen fertilization (1,412.43 kg ha-1). Therefore, nitrogen fertilization increased crop yield and favored it competitively in relation to weeds by increasing the weed PPI.