to study the effects of plant density and nitrogen rates on the ability of canola (regent cobra; an inbred variety) to compete with weeds, an experiment was conducted as a factorial complete block design with four replications. the treatments included four levels of plant density at 150, 190, 230, and 270 plants m-2, and four levels of nitrogen (n) fertil-izer at 0, 46, 92, and 138 kg ha–1. r...