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AG-01 / AUTIXON ENGINEERING

Crop Water Requirement

Determine ETc, net and gross irrigation demand from explicit agronomic inputs.
USER INPUT

Calculation inputs

Saved locally

Empty fields are never replaced with invented agronomic values. Results update only from visible data.

Crop and planting

Water balance

Advanced — soil water balance
METHOD / TRACEABILITY

Visible formulas and assumptions

ETc = ET0 × Kc | Net = max(0, ETc − pluie efficace) | Brut = Net ÷ efficience
  • ET0: — mm/j — User input
  • Kc: — — User input
  • Conversions: 1 mm over 1 m² = 1 litre; average month = 365.25 ÷ 12 days.
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Engineering reference

Crop Water Requirement Calculator

Estimate daily and seasonal irrigation demand from crop evapotranspiration, effective rainfall, cultivated area and application efficiency.

Calculation method

The calculator derives crop evapotranspiration from ET₀ and Kc, subtracts effective rainfall, then converts net depth to gross volume using the entered irrigation efficiency.

Formulas used

  • ETc = ET₀ × Kc
  • Net depth = max(0, ETc − effective rainfall)
  • Gross volume = net depth × area / irrigation efficiency

Worked example

For 1 ha, ET₀ 5 mm/day, Kc 0.8, 1 mm/day effective rain and 80% efficiency: gross demand is 37.5 m³/day.

How to interpret the result

Use the gross volume to size daily delivery; verify local ET₀, crop stage and effective rainfall before design.

Common mistakes

  • Using rainfall instead of effective rainfall.
  • Applying one Kc to the entire season.
  • Confusing millimetres over hectares with litres per plant.

Scope and limitations

  • This deterministic estimate does not replace local soil, climate or agronomic validation.

Frequently asked questions

What is ET₀?

Reference evapotranspiration represents atmospheric demand for a standardized reference surface.

Where does Kc come from?

Use a crop coefficient appropriate to the crop, growth stage and local agronomic reference.

Why divide by efficiency?

The field must receive more gross water than its net requirement when application losses exist.