The research was carried out in the years 2008–2010 in the fields of the Experimental Station IUNG at Jelcz-Laskowice. Two-factorial experiments were laid out on the grey-brown podzolic soil formed out of loamy sand silt by the method of randomized subblocks in four replications. The experimental factors were intercrops (mustard and lupine) and tillage system (traditional, simplified and zero). Winter wheat was the forecrop and maize the sequent plant. Leaf area index (LAI) and mean tip angle (MTA) were determined in the stage of early flowering with use of a LAI-2000 meter (LI-COR, USA) in four replications. The research was carried out to find out which tillage system and intercrop would positively influence the yielding, selected indices of canopy architecture (height of plants, LAI, MTA) and the amount of weeds in maize grown for grain. The yield of maize grain grown in simplified and zero tillage appeared to be lower than that obtained in traditional tillage. The highest LAI index of maize grown after both forecrops was found with traditional tillage, while the lowest with zero one. The highest maize plants were those in conventional tillage. The intercrop which appeared to have the most favourable effect on the height of maize was mustard. Reduced tillage systems increased total weed infestation in comparison to conventional tillage. Compensation of Echinochloa crus-galli, Geranium pusillum and Chenopodium album was noticed. The greatest number of weeds per unit area was found in the experiment after no-tillage system.