关键词: 春小麦, 灌溉定额, 光合特征, 光响应模型

Abstract: In order to improve the light energy utilization efficiency of spring wheat and optimize field management, the suitable light response curve model of spring wheat under drip irrigation in Ningxia Yellow River irrigation area was studied. In this experiment, spring wheat was selected as the research object. Five irrigation water gradients were set under drip irrigation, which were 1 350 m3/hm2, 1 950 m3/hm2, 2 400 m3/hm2, 2 850 m3/hm2, and 3 150 m3/hm2, respectively. The photosynthetic response process of spring wheat under five treatments was fitted and compared by right angle hyperbola model, non right angle hyperbolic model, index model, leaf floating model and dynamic model respectively, and the optimal model was selected, and the photosynthetic characteristic parameters of spring wheat under different irrigation treatments were calculated. The results showed that with the increase of irrigation amount, the net photosynthetic rate of wheat leaves increased, and the booting stage was larger than the filling stage. The root mean square error (RMSE) of each model was between 1.19 and 1.55 μmol/(m2·s) at the filling stage of treatment 1. The root mean square error of treatment 4 ranged from 0.85 μmol/(m2·s) to 1.12 μmol/(m2·s), and other error indexes were similar, indicating that the simulation effect of appropriate irrigation amount was better. The light response curve obtained by leaf drift model was more accurate and closer to the actual photosynthetic characteristics of spring wheat, which was the optimal light response model for the growth of spring wheat in Ningxia Yellow River irrigation area. Under the condition of drip irrigation in Ningxia Yellow River irrigation area, the adaptability of spring wheat to light and the utilization rate of effective radiation can be increased by properly increasing irrigation amount. The dark respiration rate and light compensation point of spring wheat are the largest under the irrigation amount of 3 150 m3/hm2. It can be seen that under drip irrigation, the light saturation point and effective photosynthetic range of spring wheat can be increased when the irrigation amount is more than 2 400 m3/hm2, which lays the foundation for increasing yield.

Key words:  spring wheat, irrigation quota, photosynthetic characteristics, light response model