Water use efficiency of controlled alternate irrigation on wheat/faba bean intercropping

Water supply is limited worldwide and there is a need for saving of water in irrigation. In this study, two irrigation methods, that is, conventional irrigation (CI), alternate irrigation (AI, alternate watering on both sides of the row), and three planting patterns, that is, sole wheat, sole faba bean and wheat/faba bean intercropping were applied on root box experiment. Results showed that the yields of intercropping with AI generally increased compared with sole cropping. Sole faba bean and wheat/faba bean intercropping with AI significantly increased the root-shoot ratio compared to all the other treatments. Pn in AI was not reduced significantly when compared to that of CI at the same planting pattern. However, Tr and Gs in AI was significantly lower than that of CI for sole wheat, sole faba bean and wheat/faba bean intercropping. Maximum biomass accumulation was obtained in the CI treatment, but severe water deficit led to a less reduction in the AI treatment, such reduction was much smaller under AI and therefore the higher water use efficiency was obtained. In conclusion, AI is an effective and water-saving irrigation method in wheat and faba bean production especially in intercropping system, and may have the potential to be used in the field.