كليدواژه :
رقابت چندگونه اي , سويا , توق , تاج خروس
چكيده لاتين :
The prevalence of weeds in crops, with soybean being no exception, is a serious threat to the yield. Little research has been carried out to address the multiple weed species interference in soybean. A field experiment was conducted at the Research Farm of University of Tehran, Karaj, Iran during the growing season of 2006-2007 to determine the effects of different densities of single and multispecies populations of common cocklebur and red root pigweed on soybean yield as well as its yield components. Common cocklebur and red root pigweed were established at densities of 0, 2, 4, 8 and 0, 4, 8, 12 plants per one meter of row. Common cocklebur and red root pigweed seeds were sown concurrently with soybean and established at selected densities within 15 cm from either side of each soybean row respectively. The experimental design was randomized complete block with three replications. Results showed that biological and grain yield, pods per plant, weight of pods per plant as well as main stem height were significantly affected by densities of either common cocklebur or red root pigweed (p<0.05). Harvest index were not significant. Maximum soybean yield loss ranged from 39 to 86%, depending upon total density of weeds. Common presence of cocklebur and red root pigweed reduced soybean biomass, number, and weight of pods per plant 79.9, 76, and 82% respectively. With increase in weed density, plant height increased except for the densities of 2 and 4 weed plants per row of crop, for common cocklebur and red root pigweed, respectively.
