مقایسه راندمان جذب، مصرف و بهره وری آب در سیستم های تک کشتی و چندکشتی کلزا (Brassica napus L.)، لوبیا (Phaseolus vulgaris L.) و ذرت (Zea mays L.)

Abstract

In order to evaluate water capture and use efficiency and also productivity in sole and intercropping of three crops Rapeseed, Bean and Corn, an experiment was conducted in Mashhad in the growing season of 2007-2008. In this investigation six treatments including three sole cropping of the three crops (rapeseed sown in 22 September 2007, bean and corn in 29 April 2008) and three intercropping including double cropping (simultaneous sowing of corn and bean in 29 April 2008), two stage-relay intercropping of rapeseed, corn and bean (rapeseed in 22 September 2007, bean and corn in 29 April 2008) and finally three stage-relay intercropping of rapeseed, corn and bean (rapeseed sown in 22 September 2007, bean in 8 April 2008 and corn in 29 April 2008) were arranged in a complete randomized block design with three replications. Results showed that in general, cropping combination affected water capture and use efficiency and also water productivity (p≤0.01). Among intercropping treatments, two stage-relay intercropping showed the highest capture efficiency (0.43), three stage-relay intercropping had the highest water use and productivity in terms of biological yields (1.82 and 0.73 g/m2/mm, respectively) and double cropping showed the highest water use efficiency and productivity in terms of seed yield (0.43 and 0.17 g/m2/mm, respectively). Among sole cropping treatments, rapeseed showed the highest capture efficiency (0.26), use efficiency and productivity in terms of biological yields (6.82 and 1.75 g/m2/mm, respectively) and corn showed the highest use efficiency and productivity in terms of seed yield (1.5 and 0.35 g/m2/mm, respectively). In general, two stage-relay intercropping for capture efficiency, sole cropping of rapeseed for use efficiency and productivity in terms of biological yield, and sole cropping of corn for use efficiency and productivity in terms of seed yield were superior than others. However, it seems that such combinations of crops for different reasons may not perform satisfactory results because of shading effect of rapeseed on young seedlings of corn and bean. Therefore, the design of these experiments should be altered in such a way to achieve in shortest overlapping of the growth of rapeseed with companion crops.