1. What is Vapor Pressure Deficit?

Vapor Pressure Deficit (VPD) is the difference between the amount of moisture in the air and how much moisture the air can hold when it's saturated. It's an important metric in agriculture and plant physiology.

2. How Does the Calculator Work?

The calculator uses the VPD equation:

Where:

• \( SVP \) — Saturation Vapor Pressure (kPa)
• \( RH \) — Relative Humidity (%)

Explanation: The equation calculates the difference between the actual water vapor pressure and the saturation water vapor pressure at a particular temperature.

3. Importance of VPD Calculation

Details: VPD is crucial for understanding plant transpiration rates, managing greenhouse environments, and optimizing plant growth conditions.

4. Using the Calculator

Tips: Enter Saturation Vapor Pressure in kPa and Relative Humidity in percentage (0-100%). All values must be valid (SVP > 0, RH between 0-100).

5. Frequently Asked Questions (FAQ)

Q1: What is a good VPD range for plants?
A: Optimal VPD varies by plant species and growth stage, but generally ranges between 0.8-1.2 kPa for most plants.

Q2: How does temperature affect VPD?
A: Warmer air can hold more water vapor, so temperature directly affects SVP and thus VPD.

Q3: Why is VPD important in agriculture?
A: VPD helps determine when plants will open or close stomata, affecting photosynthesis and water use efficiency.

Q4: What's the relationship between VPD and transpiration?
A: Higher VPD generally increases transpiration rates as the gradient for water vapor loss from leaves increases.

Q5: Can VPD be too high or too low?
A: Yes, both extremes can stress plants - too high causes excessive water loss, too low can limit nutrient uptake and promote disease.