the effect of additive maize-bean intercropping on yield, yield components and weeds control in zanjan climate conditions

increasing diversity and apply intercropping systems is one of approaches to control of weeds. to evaluate the effects of additive maize-bean intercropping on yield, yield components and weeds in zanjan conditions, a field study was conducted in a spilt plot with randomized complete block design in three replications at research farm of zanjan university in 2010. main plots were the different patterns of additive intercropping systems in 6 levels included: sowing 20, 40, 60 and 80% of bean optimum density + 100% of maize optimum density and sole cropping of the crops and sub-plots were control and non-control of weeds. density and biomass of weeds was sampled during growth season for comparing the amount of weeds control among different treatments. yield and yield components of two crops were measured at the harvest time and advantage of intercropping was calculated by use of intercropping evaluation indices. the results showed that the most of weeds control was obtained in 80% bean+100% maize (reduction of 70% compared to sole cropping) and the highest and lowest yield of maize under non-control of weeds conditions were observed in 60% bean + 100% maize (7813 kg ha-1) and sole cropping (6530 kg ha-1) treatments, respectively. according to the all of indicators, intercropping had advantages compared to the monoculture of the crops. the intercropping of 80% bean + 100% maize had the highest advantage based on land equivalent ratio (ler), actual yield loss or gain (ayl) and intercropping advantage (ia) but the highest advantage was obtained in the treatment of 60% bean + 100% maize by relative value total (rvt) indicator and the intercropping of 40% bean + 100% maize showed the highest value as used of relative crowding coefficient (rcc).