Plant competition in its basic sense can be defined as competition for resources such as light, water and nutrients. The intensity of crop competition, especially competition of row crops such as maize, mostly depends on population density and plant arrangement. A better use of maize plant density and row spacing may be one way of developing crops that would be more competitive against weeds. An IWM programme should attempt to exploit effectively the competitive ability of crops in suppressing weed growth. Weed suppression is one potential benefit of altered population density and sowing pattern of maize. Another one is an increase in grain yield.