Mechanism and Water-Saving Efficiency of Alternate Watering in Vertical Profile

Under the condition of control test, by cultivating in pots containing soil, with maize as material, the new water saving technology which was named the Control Root splited Alternate Irrigation (CRAI) was studied. The treatment included Surface Irrigation(SI), Low Irrigation (LI) and CRAI (CAI). The period of irrigation was 3d, 5d and 7d, separately. The watering amount was the same with the same period of irrigation. The result showed that the distribution model of carbohydrate was changeable. And more photosynthetic products were transformed to shoot. Besides, Crop growth of CAI with 5 days was improved than that of SI with 3 days and water use efficiency (WUE) was increased by 26%. Although no difference was found between the crop growth of CAI with 7 days and that of SI with 5 days,WUE was increased by 20%. On the other hand, crop growth of SI showed a much severe inhibition in the later of jointing stage as compared with LI and CAI. It was found that the critical water potential of CAI and osmoregulation capacity was raised. This was the probable reason why yield and WUE was improved of CAI.