Applicability of stomatal conductance models comparison for persistent water stress processes of spring maize in water resources limited environmental zone

Through the Stomata of plants, water (H₂O) and carbon dioxide (CO₂) are transferred between leaves and the atmosphere. The intakes of CO₂ during photosynthesis and water loss through transpiration are facilitated by stomata. To effectively model plant transpiration, and study the mass, energy transfer between plants, and the atmosphere, stomatal conductance of plant leaves requires accurate modelling. Abnormal changes in soil moisture result from frequent droughts in water-strapped environmental regions in a warming context. This has an impact on the stomatal conductance models's applicability and, in turn, the precision of the carbon and water cycles in agro-ecosystems. Four commonly used stomatal conductance models-Jarvis, Ball-Woodrow-Berry (BWB), Ball-Berry-Leuning (BBL) and unified stomatal optimization (OS) were investigated in the simulation of spring maize during persistent water stress to determine the impact of introducing a soil moisture response function on the simulation effect of the stomatal conductance model. The results showed that the BWB model was the best model for spring maize during persistent water stress, followed by the OS and BBL models, and the Jarvis model was the worst model. The OS and BBL models' simulation effects were improved by the addition of the soil moisture response function, while the Jarvis and BWB models' simulation effects were diminished. The OS-θ model was the best, followed by the BBL-θ and BWB-θ models, and the Jarvis-θ model was the worst, according to the model simulation effect. The 95 % confidence intervals of BWB-θ and OS-θ models were simulated with the addition of the soil moisture response function. The addition of soil moisture function improved the model's applicability, allowing it to be used for a variety of relative soil moisture contents, including 13∼68 %, 13∼89 %, 13∼78 % and 13∼89 %forthe Jarvis, BWB, BBL and USO models. With or without the addition of a moisture response function, the OS model performs optimally and is appropriate for various soil moisture conditions. The study's finding may serve as a foundation for choosing an appropriate stomatal conductance model for effective simulation of carbon and water cycles of agricultural ecosystems under drought conditions in water-limited environmental regions. This may support effective use and evaluation of agricultural water resources.