Study on a Stomatal Conductance Model of Grape Leaves in Extremely Arid Areas

Abstract

Stomata are essential for regulating the exchange of water and energy between plants and the atmosphere. In the context of climate warming, especially in extremely arid regions, the knowledge of stomatal conductance variation patterns is fundamental to the study of crop evapotranspiration, productivity and drought resistance characteristics. The accurate simulation of stomatal conductance in this region is an important prerequisite for the optimal regulation of the crop growth environment. In this study, a two-year field experiment was carried out in vineyards in an extremely arid region. The Jarvis model and BWB model were used to evaluate the daily changes in stomatal conductance. The results showed that stomatal conductance was significantly correlated with environmental factors (temperature difference between leaf and air (ΔT), photosynthetically active radiation and air temperature). The Jarvis and BWB models performed well. However, the response function of the environment factor in the Jarvis model can affect the model performance. The ΔT effectively improved the model, and the modified Jarvis model outperformed the modified BWB model. The R2 and model slope b of the modified Jarvis model increased by 45.18–70.37% and 2.51–3.12%, respectively. RMSE and MAE decreased by 38.98–43.12% and 42.69–44.35%, respectively. Overall, the Jarvis3–ΔT model had a good effect on the simulation of the daily change of stomatal conductance during the critical period of grape growth, and the Jarvis3–ΔT model was the best stomatal conductance model in this study. The results of the study are of great significance for further improving the sustainable use of water resources in grapevines in extremely arid regions.