Evaluating the Allelopathic Potential of Rapeseed Residues for Maize and Some of Its Common Weeds

This study was conducted to investigate the allelopathic potential of rapeseed (Brassica
napus L.) for seed germination and also seedling growth of maize (Zea mays L.) and some
of its common weeds. The laboratory treatments included different concentrations of rapeseed aqueous extracts (0, 15, 30, and 45 gr.in 100 ml-1 water) and plant species of
redroot amaranth (Amaranthusretroflexus L.), field bindweed (Convolvulus arvensis L.),
Johnson grass (Sorghum halepense (L.)Pers.), curly dock (Rumexcrispus L.), and maize. In
addition, the allelopathy potential of the biomass in rapeseed shoot parts (0, 15, and 30 gr. of apeseed biomass per 100 gr soil) for the emergence and growth of maize, redroot amaranth, nd Johnson grass was determined under greenhouse conditions.Rapeseed aqueous extracts eft a negative effect on germination and seedling growth parameters of weeds. The highest ensity of rapeseed biomass reduced the seedling emergence of redroot pigweed and ohnson grass up to 83% and 75%, respectively. The length of root and shoot were reduced ignificantly by all levels of rapeseed biomass. In contrast, there was not a considerable mpact on germination and growth indices of maize, especially in low densities of rapeseed iomass. Redroot pigweed and curly dock were more sensitive to inhibitors of rapeseed than ther weeds. On the basis of the results, it can be concluded that winter rapeseedcan be used or weed suppressionin maize and consequently for minimizing herbicide consumption.