Effect on canopy structure based on growth characteristics of two red bean cultivars under sole and inter cropping conditions at different cultivation densities and weed management

To evaluate the effects of plant density and reduced herbicide concentrations on the vertical distribution pattern of leaf area in red bean canopy profile in mixed bean cultivars, an experiment was conducted in a double-cropping plot design with 3 replications in the research farm of Tehran University in 2016. In this experiment, the reduced concentrations of herbicide at 5 levels (0%, 25%, 50%, 75% and 100% of recommended concentration with hand weeding treatment) were the main plots, bean plant density at three levels (40, 50 and 60 plants). M / s) were sub plots and pure cultivation system of standing cultivar and 50%-50% mixed cultivation in row of standing and creeping cultivars were sub-plot. The results showed that herbicide concentration increase resulted in the bean biomasses increase in different layers and the highest bean biomass (228 g/m2) was observed in the intercropping system and 60 plants/m2 density f in the hand weeding treatment in 30-40 cm layer and the lowest (123 g/m2) was obtained in pure planting system and 40 plants/m2 density at 0% of herbicide concentration in 50-40 cm layer. The interactions of herbicide application and cultivation system and also herbicide application and planting density were significant on bean yield and with increasing the herbicide concentration and plant density, bean seed yield increased. Based on the results of weed biomass analysis, imazapapir alone was able to reduce weed biomass up to 65%, and this was increased up to 75% under mixed cropping system and increase in density conditions. This suggests that increasing crop competitiveness by increasing plant density and using a mixed crop system instead of a single-crop system, can reduce weed biomass through faster and greater crop formation.