Irrigation regime of spring maize in songnen plain by WOFOST and CROPWAT model

WOFOST model was used to simulate potential and rain-fed yield at five typical sites in the Songnen Plain in typical years. FAO-recommended CROPWAT was used to optimize spring maize water distribution, to exploit crop production potential and optimize water distribution during crop growth period. Potential yields in wet year, normal year and dry year in the Songnen Plain were estimated to be 7.43 - 11.59, 5.94 - 10.18 and 7.20 - 10.57 t • hm^-2 respectively. Potential yields at Fuyu and Tailai were 3 - 5 and 2 - 4 t • hm^-2 respectively. Potential yields in Changling in normal year was 3.85 t •hm^-2. In irrigation regime, water demand of crops in dry, normal and wet years was 480 - 560 mm, total water requirements for irrigation were 216.7 - 300.2 , 215.2 - 272.9 and 102.9 - 234.9 mm respectively. Crop development period and mid-term in the Songnen Plain were critical periods for spring maize irrigation. The amount of irrigation water requirement for crops at different growth stages was: mid-term development period maturity initial growth period.