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基于北方农牧交错带主要作物马铃薯和油葵的叶片气孔导度、净光合速率和气象因子的平行观测数据,对常用气孔导度模型(Jarvis模型、Ball-Berry模型、Leuning模型和Medlyn模型)进行了适用性评价.结果表明:马铃薯的气孔导度与净光合速率呈现较强的线性关系,而油葵气孔导度与净光合速率的线性关系较弱.对于马铃薯气孔导度,Ball-Berry模型模拟效果最佳,Leuning模型和Medlyn模型次之,Jarvis模型模拟效果最差;各模型的模拟值与观测值的均方根误差(RMSE)分别为0.0331、0.0371、0.0456和0.0794 mol·m~(-2)·s~(-1),归一化均方根误差(NRMSE)分别为26.8%、30.0%、36.9%和64.3%,拟合度(R~2)分别为0.96、0.61、0.91和0.88.对于油葵的气孔导度,Jarvis模型模拟效果略好于Ball-Berry模型、Medlyn模型和Leuning模型,其RMSE分别为0.2221、0.2534、0.2547和0.2758 mol·m~(-2)·s~(-1),NRMSE分别为40.3%、46.0%、46.2%和50.1%,R~2分别为0.38、0.22、0.23和0.20.气象因子对气孔导度作用的通径分析表明,北方农牧交错带马铃薯和油葵气孔导度日变化主要受饱和水汽压差影响.模型评价结果表明用于油葵的气孔导度模型需要进一步改进.
Based on the parallel observation data of leaf stomatal conductance, net photosynthetic rate and meteorological factors of potato and sunflower, which are the main crops in the ecotone between agriculture and animal husbandry in North China, the common stomatal conductance models (Jarvis model, Ball-Berry model, Leuning model and Medlyn model) The results showed that there was a strong linear relationship between stomatal conductance and net photosynthetic rate of potato, while the linear relationship between stomatal conductance and net photosynthetic rate of potato was weak.For the stomatal conductance of potato, Ball-Berry The results of model simulation are the best, followed by Leuning model and Medlyn model. Jarvis model has the poorest simulation effect. The root mean square error (RMSE) of simulation and observed values of each model are 0.0331, 0.0371, 0.0456 and 0.0794 mol · m ~ (-2) · s ~ (-1) and normalized root mean square error (NRMSE) were 26.8%, 30.0%, 36.9% and 64.3%, respectively. 0.91 and 0.88, respectively. For the stomatal conductance of oil sunflower, the simulation results of Jarvis model are slightly better than that of the Ball-Berry model, the Medlyn model and the Leuning model, with RMSE of 0.2221, 0.2534, 0.2547 and 0.2758 mol · m -2 s ~ (-1) and NRMSE were 40.3%, 46.0%, 46.2% and 50.1% respectively, and R ~ 2 were 0.38 , 0.22, 0.23 and 0.20, respectively.The path analysis of meteorological factors on stomatal conductance showed that the diurnal variation of stomatal conductance in potato and oil sunflower was mainly affected by the pressure difference of saturated vapor in the farming-pastoral zone of north China.The model evaluation results showed that the application of stomatal conductance Stomatal conductance model needs further improvement.