A field experiment was conducted during kharif 2007 at the Main Research Station, University of Agricultural Sciences, Hebbal, Bangalore, under irrigated conditions to know the pattern of dry matter production in maize using empirical models under weed management practices. Empirical models simulated the crop growth (dry matter production) of maize by 98% indicating that competition of weed types did not alter the pattern of growth of maize, but cumulatively affected the total dry matter at harvest, where as, the linear function predicted the crop growth by 92 to 94%. Differentiating quadratic and linear functions indicated that dry matter production efficiency (DMPE) were improved by 34 to 46% in hand weeding or atrazine treatments due to elimination of weed competition over unweeded control. Competition of grassy weeds (in 2,4-D EE treatment) lowered the DMPE by 24% over atrazine treatment with less weed competition, while competition from broad leaf weeds and sedge lowered the DMPE by 22%. Thus grasses showed higher competitive ability, followed by broad leaf weeds and sedges.