Watering and Irrigation
Crop Coefficient Water Use Calculator
Crop Coefficient Water Use uses its formula to estimate crop evapotranspiration from reference ET and a crop coefficient. Its crop et output is tied to reference et and crop coefficient.
Enter values for crop et
Crop Coefficient Water Use needs reference et and crop coefficient from one case.
How Crop Coefficient Water Use performs the calculation
Crop Coefficient Water Use multiplies factors from Reference ET and Crop coefficient to produce crop et.
The starting case sets reference et at 0.22 in/day and crop coefficient at 0.78. Its crop et is 0.17 in/day. Keep replacement depth in a separate Soil Moisture Replacement Calculator case.
Interpreting this crop et value
Read Crop ET as the answer to “Estimate crop evapotranspiration from reference ET and a crop coefficient.” Keep the Crop Coefficient Water Use units attached.
Measurements for Crop Coefficient Water Use
The Crop Coefficient Water Use input panel defines Reference ET and Crop coefficient. Note any Crop Coefficient Water Use conversion.
- Reference ET
- Default in Crop Coefficient Water Use: 0.22 in/day.
- Crop coefficient
- Default in Crop Coefficient Water Use: 0.78.
A practical check for reference et
Save the weather date with crop et. Temperature, wind, humidity, and plant size can change the next schedule.
Crop ET: practical constraint
Crop coefficients vary with stage, canopy, and local method. Continue with Container Watering Volume Calculator to estimate a container watering dose as a fraction of container volume.
Documenting crop et
Date the Crop Coefficient Water Use case and retain Reference ET and Crop coefficient. Compare this result with Irrigation Efficiency Adjustment Calculator when gross irrigation depth is also needed.
Record how reference et was obtained and whether a conversion or estimate was involved.
Use the same crop et units for the observed outcome so the comparison remains meaningful.
Reviewing a change in reference et
A second person should be able to reproduce crop et from the Crop Coefficient Water Use notes.
Keep the first reference et value when creating a revised scenario. Use the Effective Rainfall tool when effective rainfall needs its own calculation.
Crop ET questions
How does “Crop coefficients vary with stage, canopy, and local method.” affect crop et?
Represent that condition through a corrected reference et value rather than adding an unexplained allowance afterward.
Does Crop Coefficient Water Use adjust itself as crop demand changes?
No. Recalculate crop et after meaningful changes in weather, canopy size, root depth, or irrigated area.