additive intercropping of marigold (calendula officinalis) and mungbean (vigna radiata): a strategy for yield improvement and weeds control

intercropping systems lead to reduce weeds population and their biomass. in order to study effect of marigold (calendula officinalis) and mungbean (vigna radiata) intercropping in different sowing times on yield and weeds control a factorial experiment based on randomized complete block design was performed in islamic azad university, tabriz branch, iran, during 2012 in three replications. studied treatments were mungbean sowing times (10 days earlier, simultaneously and 10 days after marigold) and its mixing rates (0, 12.5%, 25%, 37.5% and 50% of recommended rate). mungbean mixing rates of 12.5% and 25% lead to higher weeds biomass, but higher mixing rates caused to restriction of weeds growth. in earlier sowing times weeds were better controlled. mungbean in two higher mixing rates as intercropped with marigold produced 22.4 pods per plant, while its sole cropping produced 24 pods. with increasing of mungbean mixing rate its grain yield increased as intercropped with marigold. when mungbean was sown 10 days after marigold, its grain yield was higher (317 kg/ha). increasing of mungbean mixing rate from 12.5% to 37.5% improved dry flower yield of marigold up to 11%. standarized land equivalent ratio in second and third sowing dates were greater than first sowing time. in intercropping of mungbean with mixing rate of 37.5% at 10 days after marigold or simultaneous intercropping yield could improve due to better weeds control.