Agricultural Water Management 68 (2004) 117–133 Simulation of water dynamics and irrigation scheduling for winter wheat and maize in seasonal frost areas Songhao Shang a,∗ , Xichun Li a , Xiaomin Mao b , Zhidong Lei a a Department of Hydraulic Engineering, Tsinghua University, Beijing 100084, China b Institute for Infrastructure and Environment, School of Engineering and Electronics, The University of Edinburgh, Edinburgh EH9 3JN, UK Accepted 24 March 2004 Abstract Continuous cropping of winter wheat and summer maize is the main cropping pattern in North China Plain lying in a seasonal frost area. Irrigation scheduling of one crop will influence soil water regime and irrigation scheduling of the subsequent crop. Therefore, irrigation scheduling of winter wheat and maize should be studied as a whole. Considering the meteorological and crop characteristics of the area lying in a seasonal frost area, a cropping year is divided into crop growing period and frost period. Model of simultaneous moisture and heat transfer (SMHT) for the frost period and model of soil water transfer (SWT) for the crop growing period were developed, and used jointly for the simulation of soil water dynamics and irrigation scheduling for a whole cropping year. The model was calibrated and validated with field experiment of winter wheat and maize in Beijing, China. Then the model was applied to the simulation of water dynamics and irrigation scheduling with different precipitation and irrigation treatments. From the simulation results, precipitation can meet the crop water requirement of maize to a great extent, and irrigation at the seeding stage may be necessary. Precipitation and irrigation had no significant influence on evaporation and transpiration of maize. On the other hand, irrigation scheduling of winter wheat mainly depends on irrigation standard. Irrigation at the seeding stage and before soil freezing is usually necessary. For high irrigation standard, four times of irrigation are required after greening. While for medium irrigation, only once (rainy year) or twice (medium and dry years) of irrigation is required after greening. Transpiration of winter wheat is very close for high and medium irrigation, but it decreases significantly for low irrigation and will ∗ Corresponding author. Tel.: +86 10 62783176; fax: +86 10 62773046. E-mail address: shangsh@mail.tsinghua.edu.cn (S. Shang). 0378-3774/$ – see front matter © 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.agwat.2004.03.009