Vapor pressure deficit
The difference between the amount of moisture in the air and how much moisture the air can hold when saturated at a specific temperature.
Также говорят: VPD, saturation deficit
This metric indicates the atmosphere's drying power: higher values mean plants transpire more rapidly. Growers use it to manage crop health, optimize irrigation, and prevent moisture stress.
When the vapor pressure deficit is too high, plants may close their stomata to conserve water, which halts photosynthesis and stunts growth. Conversely, very low levels can inhibit nutrient uptake and promote fungal diseases.
A common mistake is neglecting the relationship between temperature and humidity. Failing to monitor these levels can lead to incorrect irrigation scheduling, causing either drought stress or waterlogging issues.