Turc Irrigation Need Calculator
Daily Turc reference ET with MJ→cal/cm²solar conversion and low RH correction; rain-only reference gap not crop irrigation prescription/soil budget. Caller independently establishes homogeneous observation coverage and model/reference applicability; not observed future climate, crop suitability or validated drought severity.
Description
A Turc-style reference evapotranspiration estimate combines temperature, radiation and humidity.
A Turc-style reference evapotranspiration estimate combines temperature, radiation and humidity.1
Subtracting effective rainfall gives a limited water-gap scenario rather than a complete irrigation schedule. Use Turc Irrigation Need Calculator to evaluate the supplied inputs under the model explained below.
When to use Turc Irrigation Need Calculator
Use Turc Irrigation Need Calculator to evaluate the supplied inputs under the model explained below. Establish the units, measurement scope and model assumptions before entering values.
How to use Turc Irrigation Need Calculator and understand its results
- Establish the units, measurement scope and model assumptions before entering values.
- Enter Observed daily mean temperature c, Observed daily solar m j per m2, Observed mean relative humidity percent, Independently effective rain mm using the field table and validation rules below, then run the tool.
- Read Turc reference et mm, Conditional rain only irrigation gap mm; interpret the units, signs, ordering and unknown-value placeholders described below.
- Correct reported input errors and rerun. Apply successful results according to their specific meanings and check the assumptions before using them in a decision.
| Input field | Meaning | Value type | Requirement |
|---|---|---|---|
| observedDailyMeanTemperatureC | Observed daily mean temperature c | number | Required; constraints below |
| observedDailySolarMJPerM2 | Observed daily solar m j per m2 | number | Required; constraints below |
| observedMeanRelativeHumidityPercent | Observed mean relative humidity percent | number | Required; constraints below |
| independentlyEffectiveRainMm | Independently effective rain mm | number | Required; constraints below |
Enter a strictly positive daily mean temperature in °C, nonnegative daily solar energy in MJ/m² and effective rain in mm, and relative humidity from 0 to 100 percent. Compute 0.013×T/(T+15)×(23.8856×radiation+50), multiplying by 1+(50−RH)/70 only below 50 percent humidity. Return that Turc-style ET estimate in mm and max(0,ET−effectiveRain). Soil storage, crop factors and delivery losses are outside this rain-only scenario.
ETmm = 0.013×T/(T+15)×(23.8856×solar+50)×humidityFactor; gapMm=max(0,ETmm−effectiveRainMm) Use the field order, units and branch conditions described above.
| Output field | Meaning | Value type |
|---|---|---|
| turcReferenceEtMm | Turc reference et mm | number |
| conditionalRainOnlyIrrigationGapMm | Conditional rain only irrigation gap mm | number |
{
"input": {
"observedDailyMeanTemperatureC": 20,
"observedDailySolarMJPerM2": 10,
"observedMeanRelativeHumidityPercent": 50,
"independentlyEffectiveRainMm": 1
},
"output": {
"turcReferenceEtMm": 2.1457874285714285,
"conditionalRainOnlyIrrigationGapMm": 1.1457874285714285
}
}Limitations and assumptions
Subtracting effective rainfall gives a limited water-gap scenario rather than a complete irrigation schedule. Apply the exact scope and assumptions explained above.
All listed fields require explicit values. Unexpected fields, incorrect types, nonfinite numbers and sparse arrays fail validation. Domain-specific bounds, alignments and supported tokens are explained above; extremely large inputs or outputs can also be rejected. Input errors differ from successful false results, empty match lists and unknown-evidence placeholders.
Alternative or Complementary methods
Use Firbas Humidity Factor Calculator for a related task: A named humidity factor requires an identified method and reference convention.
Use Runoff Coefficient Regional Estimate Lookup for a related task: An observed runoff coefficient compares matched runoff and rainfall volumes.
References
-
Turc Irrigation Need Calculator — tool.io
Similar or alternative tools
- Firbas Humidity Factor Calculator
A named humidity factor requires an identified method and reference convention.
- Runoff Coefficient Regional Estimate Lookup
An observed runoff coefficient compares matched runoff and rainfall volumes.