The Effect of Vapor Pressure Deficit Regulation on the Growth of Tomato Plants Grown in Different Planting Environments

Vapor pressure deficit (VPD) has been identified as an increasingly important driver of plant functioning, and thus VPD regulation has been widely recognized as having the potential to improve plant growth and productivity. We monitored the trend of the VPD and observed the effect of VPD regulation by irrigating the water using VPD control equipment that automatically inserts fogging water when the VPD exceeds 1.2 kPa. Tomato crops were planted in soil, coconut fiber, and soil above poly vinyl chloride trays to observe the effectiveness of VPD regulation and the planting environment. As a result, there was no significant difference in the effect of VPD regulation on the overall growth stages of tomato crops whether they grew in soil, trays with soil, or trays with coconut fiber. However, in the case of crops grown in a tray with coconut fiber, the initial growth was similar, but the total yield and total commercial yield showed approximately 89% and 88% improvement, respectively. The number of total fruits was also improved by 49% on average.