Research on the deficit irrigation scheduling to winter wheat at critical period based on crop modeling method

Less water at critical period has significant effect on crop yield.The deficit irrigation scheduling is important especially for the drought-prone area.The crop water production function frequently used for deficit irrigation analysis neither has the disadvantage in mechanism explanation.In this study, we use crop model instead of the crop water production function to study deficit irrigation scheduling issue for winter wheat in Jinan City, in North Plain of China.The crop model we employed is APSIM model.The model was calibrated and validated specifically for winter wheat in Jinan using data in 2000-2013 years.Three typical years were selected to represent the normal, light drought and drought conditions.There are 24 irrigation scheduling schemes obtained by combination of three deficit irrigation quotas, the 150 mm, 100 mm and 50 mm, and different irrigation dates from early April to mid-May.By simulating and comparing the ultimate yield of each irrigation scheduling for winter wheat in Jinan, we strongly suggest that: 1) if the antecedent soil moisture is low, perform irrigation at the beginning of critical period, 2) if it under drought stress, perform irrigation once in early May, and 3) if severe drought hits, perform irrigation twice, and allocating more quota for the second time.