Watering and Irrigation
Evapotranspiration Irrigation Need Calculator
Evapotranspiration Irrigation Need uses its formula to subtract effective rainfall from crop water use. Its net irrigation depth output is tied to crop water use and effective rainfall.
Enter values for net irrigation depth
Replace the Evapotranspiration Irrigation Need examples before using net irrigation depth.
From crop water use to net irrigation depth
Evapotranspiration Irrigation Need finds the difference using Crop water use and Effective rainfall. The Irrigation Zone Flow Calculator provides zone flow.
Using crop water use at 1.4 in and effective rainfall at 0.35 in, the example returns 1.05 in and 300.0%.
Using the Evapotranspiration Irrigation Need result
Read Net irrigation depth as the answer to “Subtract effective rainfall from crop water use.” Keep the Evapotranspiration Irrigation Need units attached.
Irrigation need relative to rainfall supplements net irrigation depth in Evapotranspiration Irrigation Need.
Evapotranspiration Irrigation Need in practical terms
Subtract effective rainfall from crop water use. Evapotranspiration Irrigation Need limits that task to Crop water use and Effective rainfall.
Save Net irrigation depth with the Evapotranspiration Irrigation Need units and scenario name.
How input changes affect net irrigation depth
A low and high case for Effective rainfall can show whether uncertainty in that input materially changes net irrigation depth.
Evapotranspiration Irrigation Need beyond the formula
Rainfall that runs off or falls outside the root zone is not effective. For replacement depth, use Soil Moisture Replacement Calculator.
Before entering crop water use
Prepare Crop water use and Effective rainfall for Evapotranspiration Irrigation Need. Keep unrelated records separate.
- Crop water use. Default in Evapotranspiration Irrigation Need: 1.4 in.
- Effective rainfall. Default in Evapotranspiration Irrigation Need: 0.35 in.
What changes when crop water use changes
In the Evapotranspiration Irrigation Need example, changing Crop water use from 1.4 in to 1.54 in produces 1.19 in rather than 1.05 in. Need days between irrigation? Open Irrigation Frequency Calculator.
Use crop water use only to compare net irrigation depth.
Pair crop water use with Evapotranspiration Irrigation Need site observations.
Clarifying the Evapotranspiration Irrigation Need result
How does “Rainfall that runs off or falls outside the root zone is not effective.” affect net irrigation depth?
Account for it in the source measurement for crop water use; the formula has no additional correction for it.
How should rainfall be handled in Evapotranspiration Irrigation Need?
Use only the effective rainfall quantity named by Evapotranspiration Irrigation Need. Keep gross rainfall and irrigation delivery as separate records.