Agriculture Crop Evapotranspiration
Integrate reference ET×caller crop coefficients across unequal stage durations, keeping modeled daily rates; no mutable crop calendar or universal Kc lookup.
Description
Crop coefficients translate reference evapotranspiration into a supplied crop-demand scenario.
Crop coefficients translate reference evapotranspiration into a supplied crop-demand scenario. Stage durations must be included when accumulating periods of unequal length.1, 2
Integrate reference ET×caller crop coefficients across unequal stage durations, keeping modeled daily rates; no mutable crop calendar or universal Kc lookup.
When to use Agriculture Crop Evapotranspiration
Use this tool to integrate reference ET×caller crop coefficients across unequal stage durations, keeping modeled daily rates; no mutable crop calendar or universal Kc lookup.
Prepare the field, crop, soil or material measurements for the intended period. Confirm units, dry/wet bases and supplied parameters; keep paired observations aligned.
How to use Agriculture Crop Evapotranspiration and understand its results
- Prepare the field, crop, soil or material measurements for the intended period. Confirm units, dry/wet bases and supplied parameters; keep paired observations aligned.
- Enter referenceEtMmPerDay, callerCropCoefficients, representedDurationsDays using the field table and calculation rules, then run the tool.
- Read modelCropEtMmPerDay, integratedCropEtMm. The explanation below defines the units, signs, ordering and any flags or placeholder values.
- If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.
| Input field | Meaning | Value type; see rules below | Requirement |
|---|---|---|---|
| referenceEtMmPerDay | Reference et mm per day | list of number | Required |
| callerCropCoefficients | Caller crop coefficients | list of number | Required |
| representedDurationsDays | Represented durations days | list of number | Required |
Pair nonnegative reference ET in mm/day and nonnegative caller crop coefficients with positive represented days. Return modeled daily rates and integrated crop ET in mm. Zero reference rates or coefficients contribute zero.
Paired lists must be nonempty and have equal lengths.
cropRate_i = referenceET_i coefficient_i; integratedMm = Σ(cropRate_i durationDays_i) Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| modelCropEtMmPerDay | Model crop et mm per day | list of number |
| integratedCropEtMm | Integrated crop et mm | number |
{
"input": {
"referenceEtMmPerDay": [
2,
4
],
"callerCropCoefficients": [
0.5,
1.5
],
"representedDurationsDays": [
1,
2
]
},
"output": {
"modelCropEtMmPerDay": [
1,
6
],
"integratedCropEtMm": 13
}
}Limitations and assumptions
No crop calendar or coefficient lookup is built in. The supplied coefficients determine the scenario, and water stress, soil evaporation and actual crop conditions are not independently fitted.
Numeric inputs must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Numeric lists are limited to 100,000 entries; the rules above may require smaller limits. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.
Alternative or Complementary methods
Use Agriculture Reference Evapotranspiration Penman Monteith: Evaluate named FAO-56 daily grass reference Penman–Monteith with caller radiation, atmospheric coefficients, 2 m wind and VPD; retains signed condensation scenarios, not hourly constants, weather derivation or actual crop ET. For a complementary task, use Agriculture Irrigation Water Requirement: Balance caller interval crop demand with already-effective rainfall and planned available soil-storage draw, then convert to gross irrigation by supplied efficiency; no storage draw beyond caller availability or irrigation scheduling recommendation.
Further background: FAO Penman–Monteith equation and reference surface.
References
Similar or alternative tools
- Agriculture Reference Evapotranspiration Penman Monteith
Evaluate named FAO-56 daily grass reference Penman–Monteith with caller radiation, atmospheric coefficients, 2 m wind and VPD; retains signed condensation scenarios, not hourly constants, weather derivation or actual crop ET.
- Agriculture Irrigation Water Requirement
Balance caller interval crop demand with already-effective rainfall and planned available soil-storage draw, then convert to gross irrigation by supplied efficiency; no storage draw beyond caller availability or irrigation scheduling recommendation.