عنوان مقاله [English]
Field experiment was conducted to evaluate competition effect of red root pigweed on growth analysis, light absorption and yield loss of two soybean cultivars under sole and intercropping. A randomized complete block design with three replications was carried out in experimental farm of College of Agriculture, University of Tehran, Karaj. Two soybean cultivars: Clark (tall) and Enterprise (dwarf) were planted under sole and intercropping in competition with redroot pigweed at densities of 0, 2, 4 and 8 plant m-2. The results showed that the decrease of soybean LAI under intercropping was less than of sole cropping in both two cultivars. Clark under intercropping and weed free condition and Enterprise under sole cropping and competing with 8 (pigweed/m2) had maximum (7.6) and minimum of LAI (2.1) respectively. Maximum light absorption in the canopy for Clark and Enterprise were 84% and 64% respectively. Leaf area density in the upper levels of the intercropped canopies were much denser, which resulted in less availability of light to pigweed plants.