Radiation Capture and Use Efficiency and Productivity in Single and

In order to evaluate radiation capture and use efficiency and productivity in sole and intercropping of three crops, rapeseed (Brassica napus L.), bean (Phaseolus vulgaris L.) and corn (Zea mays L.), an experiment was conducted in Mashhad region during the growing season of 2007-2008. In this study six treatments including three sole cropping of the crops (rapeseed sown in 22 September 2007, corn and bean in 29 April 2008) and three intercroppig including double cropping (simultaneous sowing of corn and bean in 29 April 2008), two stages-relay intercropping of rapeseed, corn and bean (rapeseed in 22 September 2007, bean and corn in 29 April 2008) and finally tree stages-relay intercropping of rapeseed, corn and bean (rapeseed in 22 September 2007, bean in 8 April 2008 and corn in 29 April 2008) were arranged in complete randomised blocks design with three replications. Based on results, cropping combination affected radiation capture and use efficiency and also radiation productivity, significantly (p≤0.05). In which, among intercropping treatments, double cropping showed the highest capture efficiency (0.54), the highest radiation use efficiency and radiation productivity in terms of seed yield (0.23 and 0.13 g.m-2.Mj-1, respectively) and also the highest radiation productivity in terms of biological yield (0.50 g.m-2.Mj-1) and tree stages-relay intercropping the highest radiation use efficiency in terms of biological yield (0.92 g.m-2.Mj-1). Among sole croppings, bean showed the highest capture efficincy (0.49) and corn the highest use efficiency in terms of biological and seed yield (1.80 and 0.65 g.m-2.Mj-1, respectively) and the highest radiation productivity in terms of biological and seed yield (0.72 and 0.26 g.m-2.Mj-1, respectively) too. In general, double cropping were the best treatment in terms of capture efficincy and corn sole croppig in terms of radiation use efficiency in terms of biological and seed yield and productivity in terms of biological and seed yield. Generally, it seems that such cropping combinations will not be suitable because of shading effect of rapeseed on young seedlings of bean and corn; therefore it is nessesary to adjust more proper planting dates in which growth period of companion crops have less overlapping with growth period of rapsee