competition of wild mustard (sinapis arvense l.) densities with rapeseed (brassica napus l.) under different levels of nitrogen fertilizer

a two year field experiment was carried out to evaluate the competitive effects of wild mustard densities growing with rapeseed (cultivar talaye) under different nitrogen rates. treatments were wild mustard densities (0, 10, 20, 30, and 40 plant m-2) and nitrogen (n) rates (0, 50, 100, 150, and 200 kg n ha-1). the factorial set of treatments was arranged into a randomized complete block design with four replications. rapeseed yield and the yield components decreased as wild mustard density increased. at 0 and 10 wild mustard plants m-2, grain yield increased with increasing n fertilizer up to 150 kg ha-1. at higher wild mustard densities, grain yield decreased above 100 kg n ha-1. these results indicate that increases in nitrogen application only increased the competitiveness of the weed versus the crop.