Effect of crop density and application of reduced dosages of two post-emergence herbicides
on broadleaf weeds biomass and yield and yield components of
broomcorn (Sorghum vulgare var. technicum)

To evaluate the effect of crop density and application of reduced dosage of two post-emergence herbicides on broom yield of broomcorn, an experiment was carried out in 2011 as factorial based on a randomized complete block design with three replications in Miyaneh region. Treatments were crop densities of 17, 24 and 31 plant. m-2 and herbicides including 2,4-D+MCPA and bromoxynil+MCPA with recommended, 20% and 40 reduced dosages. For each crop density, a hand weeding plot were considered as control. Results showed that weed biomass was decreased with crop density increasing, and recommended dosage of bromoxynil + MCPA was the most effective herbicide treatments in most sampling stages. Also, increasing crop density resulted in increased leaf number and leaf, stalk and panicle dry weight. Besides, broom yield
and
production
efforts
were significantly increased with increasing plant density. The highest broom
yield was obtained with application of
bromoxynil + MCPA and 2,4-D + MCPA in recommended dosages. The effect of recommended and 20% decreased dosages of bromoxynil + MCPA was similar on broom yield improvement. Regarding to the obtained results, plantin density of 31 plant.m-2 and 20% of recommended dosage of bromoxynil + MCPA application is recommended to weed control and broomcorn yield increment in Miyaneh region.