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How to Set a Custom Evapotranspiration (ET) Rate

Customize Evapotranspiration (ET) calculations to better match your crop's water use. You can adjust ET values, select a different Kc model, or create a custom Kc model to account for young crops, irrigation efficiency, and other site-specific conditions.

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Written by Ryan Eby

Evapotranspiration (ET) is used to estimate how quickly water is leaving the soil-plant system. ET can help you:

  • Plan future irrigations

  • Evaluate past irrigations

  • Monitor irrigations in progress

Semios calculates ET using weather data and applies a crop coefficient (Kc) to adjust values for specific crops.

If needed, you can modify the Kc model or adjust ET values to account for factors such as:

  • Irrigation efficiency losses

  • Cover crops

  • Late-season cropping

  • Young or immature permanent crops

  • Custom water use assumptions

Set Custom Rate Video

Change the Kc Model for a Block

  1. Log in to hub.semios.com.

  2. Select Evapotranspiration from the Views menu.

  3. Select the block you want to update.

  4. Select Select Kc Models in the top-right corner.

  5. Choose an available Kc model from the list.

Adjust ET Using a Percentage

You can increase or decrease the selected ET value using the adjustment slider.

Examples:

  • Increase ET to 110% to account for irrigation efficiency losses.

  • Reduce ET to 30% for a young orchard with lower water use requirements.

  1. Select Save Changes.

Create a Custom Kc Model

  1. Select Settings from the left navigation menu.

  2. Under Water Management, select Evapotranspiration.

  3. Select New Kc Model.

  4. Enter a name for the model.

  5. Select the organization and crop the model will apply to.

  6. Add Kc values for the desired time periods.

  7. Select Create Kc Model.

The new Kc model will become available for selection on applicable properties.

Set Custom Rate Video

FAQs

What is ET?

Evapotranspiration (ET) estimates how much water is being lost from the soil-plant system through evaporation and plant water use.

What is a Kc model?

A Kc (crop coefficient) model adjusts ET values to reflect the water use characteristics of a specific crop.

Why would I adjust ET values?

You may want to adjust ET values to account for irrigation efficiency, cover crops, seasonal conditions, or reduced water use in young crops.

Can I increase or decrease ET without creating a new model?

Yes. You can use the ET adjustment slider when selecting a Kc model to increase or decrease ET by a percentage.

How do I account for immature or young crops?

Reduce the ET percentage using the adjustment slider to better reflect lower water use requirements.

Can I create my own Kc model?

Yes. Custom Kc models can be created in Settings > Water Management > Evapotranspiration and assigned to the appropriate crop and organization.

Will my custom Kc model be available for my properties?

Yes. After the model is created, it can be selected from the list of available Kc models for applicable properties.

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