Effect of regulated deficit irrigation on physiological mechanism and water use efficiency of winter wheat

Under the condition of control test, by cultivating in pots containing soil, with winter wheat as material, the Regulated Deficit Irrigation (RDI) was studied. The results showed that RDI in winter wheat was a practical technology for water-saving, high-yield and high-efficiency. Under appropriate amount of water deficit at right stages, the transpiration rate decreased obviously, and the photosynthesis rate diminution was not obvious. There were super-compensation effects in photosynthesis and photosynthetic products accumulation after rewatering. The proportion of photosynthetic products distributed in the grains tends to increase. RDI was able to control vegetative growth, and promote reproductive growth. The indexes of RDI for water-saving and high-yield in winter wheat as are follows: the stage of regulated water deficit was three-leaves—returning green stages, the amount of water deficit was 40%～60%, and the water deficit duration was 55 days, RDI increased yield by 0.88%～8.25%, water consumption　decreased by 12.80%～18.55%, water use efficiency increased by 15.96%～32.98% as compared with that of conventional irrigation.