Transpiration model for plant canopy using ioT systems in the microenvironment

To ensure a consistent supply of high-quality agricultural products, managing environmental factors like temperature, humidity, and light is crucial. Plant factories are emerging as practical solutions for creating controlled environments. Our laboratory has developed a system to manage temperature and vapour pressure deficit (VPD), enabling precise control of mist cooling. Understanding the relationship between plants and water is vital, especially in adapting to regional conditions and quality targets. This study introduces an IoT system that measures VPD and weight changes due to transpiration, allowing for calculating transpiration rates and vapour conductance without damaging the plants. We measured leaf area using both destructive and nondestructive methods. Results indicated that leaf area could be estimated through destructive inspection by applying a derived equation from nondestructive methods. Additionally, we tracked weight changes from transpiration over time and derived growth rate curves. When VPD increased by 1.19 to 1.68 times compared to normal, water vapour conductance decreased by 0.42 to 0.77 times. This study highlights that transpiration is active at moderate VPD levels, but excessive VPD may trigger stomatal closure, indicating a complex interplay between environmental conditions and plant physiology.