Enter the canopy temperature, air temperature, and wet bulb temperature into the calculator to determine the Crop Water Stress Index.

## Crop Water Stress Index Formula

The following formula is used to calculate the Crop Water Stress Index (CWSI).

CWSI = (Tc - Ta) / (Tc - Tw)

Variables:

• CWSI is the Crop Water Stress Index
• Tc is the canopy temperature (°C)
• Ta is the air temperature (°C)
• Tw is the wet bulb temperature (°C)

To calculate the Crop Water Stress Index, subtract the air temperature from the canopy temperature. Then subtract the wet bulb temperature from the canopy temperature. Divide the first result by the second result to get the Crop Water Stress Index.

## What is a Crop Water Stress Index?

The Crop Water Stress Index (CWSI) is a numerical value that indicates the level of water stress experienced by a crop at a given time. It is a tool used in agriculture to manage irrigation and monitor plant health. The index is calculated using measurements of the crop’s canopy temperature, ambient temperature, and relative humidity. A high CWSI value indicates severe water stress, which can negatively affect crop yield and quality. Conversely, a low CWSI value suggests that the crop is adequately hydrated.

## How to Calculate Crop Water Stress Index?

The following steps outline how to calculate the Crop Water Stress Index (CWSI) using the formula: CWSI = (Tc – Ta) / (Tc – Tw).

1. First, determine the canopy temperature (Tc) in degrees Celsius.
2. Next, determine the air temperature (Ta) in degrees Celsius.
3. Next, determine the wet bulb temperature (Tw) in degrees Celsius.
4. Use the formula CWSI = (Tc – Ta) / (Tc – Tw) to calculate the Crop Water Stress Index.
5. After inserting the values of Tc, Ta, and Tw into the formula, calculate the result.

Example Problem:

Use the following variables as an example problem to test your knowledge:

Canopy temperature (Tc) = 28°C

Air temperature (Ta) = 25°C

Wet bulb temperature (Tw) = 20°C