Allelopathy plays a major role in both natural and managed ecosystems for ecological weed management. In order to study the impacts of different concentrations of caraway (Bunium persicum L.) seeds on decreasing in germination characteristics and preliminary growth of amaranth (Amaranthus retroflexus L.) and barnyardgrass (Echinochloa crus-galli L.), an experiment was performed based on completely randomized design with six replications at the Special Crop laboratory, College of Agriculture, Ferdowsi University of Mashhad, during year of 2010. Treatments were five concentrations of caraway essential oil including 0, 100, 200, 400 and 800 ppm. The results indicated that the effect of different concentrations for essential oil caraway was significant (p≤0.05) on final germination (FG), mean germination time (MGT), germination rate (GR) and radicle and plumule lengths for amaranth and barnyardgrass. By increasing in essential oil concentration FG, GR and radicle and plumule lengths were declined and MGT was enhanced for two weeds. With increasing in essential oil concentration from zero to 800 ppm declined MGT for up to 89 and 90%amaranth and barnyardgrass, respectively. The effect of caraway on decreasing of germination characteristics for amaranth was higher than barnyardgrass. It was concluded that caraway essential oil could be considered as an ecological approach for weed control in organic agriculture.

Keywords