宁夏引黄灌区不同灌水处理下春小麦光响应曲线模型研究

Study on light response curve model of spring wheat under different irrigation treatments in Ningxia Yellow River irrigation area

为提高春小麦光能利用效率、优化田间管理,开展滴灌条件下宁夏引黄灌区春小麦适宜的光响应曲线模型研究。试验以春小麦为研究对象,设置滴灌条件下5个灌水量梯度,分别为1350 m^(3)/hm^(2)、1950 m^(3)/hm^(2)、2400 m^(3)/hm^(2)、2850 m^(3)/hm^(2)、3150 m^(3)/hm^(2)。测定5个处理下春小麦的光合响应过程,采用直角双曲线模型、非直角双曲线模型、指数模型、叶子飘模型、动力学模型分别对春小麦光响应曲线进行拟合比较,筛选出最优模型,并对不同灌溉处理下春小麦的光合特征参数进行计算。结果表明:随着灌溉量的增加,小麦叶片净光合速率呈增加趋势,且孕穗期大于灌浆期,各模型对处理1灌浆期光响应过程模拟的均方根误差(RMSE)介于1.19~1.55μmol/(m^(2)·s)之间,而处理4的均方根误差为0.85~1.12μmol/(m^(2)·s),其他误差指标类似,均表现为灌水量适宜的模拟效果较好。叶子飘模型拟合得出的光响应曲线精度更高,更接近于春小麦实际的光合特征,是适合宁夏引黄灌区春小麦生长的最优光响应模型。在宁夏引黄灌区滴灌条件下,适当增加灌水量,可增加春小麦对光的适应能力和有效辐射利用率,灌水量3150 m^(3)/hm^(2)的处理暗呼吸速率和光补偿点最大。可见滴灌条件下灌水量大于2400 m^(3)/hm^(2)时可增大春小麦光饱和点,增加有效光合范围,为增产奠定基础。

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 1350 m^(3)/hm^(2),1950 m^(3)/hm^(2),2400 m^(3)/hm^(2),2850 m^(3)/hm^(2),and 3150 m^(3)/hm^(2),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 1.55μmol/(m^(2)·s)at the filling stage of treatment 1.The root mean square error of treatment 4 ranged from 0.85μmol/(m^(2)·s)to 1.12μmol/(m^(2)·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 3150 m^(3)/hm^(2).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 2400 m^(3)/hm^(2),which lays the foundation for increasing yield.