Evapotranspiration Calculator
Calculate reference evapotranspiration (ET₀) using the FAO Penman-Monteith method. Determine crop water requirements for irrigation planning and water management.
Step 1: Climate Data
Climate Data Requirements
Reference evapotranspiration (ET₀) is calculated using the FAO Penman-Monteith equation, which requires temperature, humidity, wind speed, and solar radiation data for accurate results.
Step 2: Crop & Area Details
Crop Coefficient (Kc)
The crop coefficient adjusts reference ET₀ to specific crop water requirements. Kc varies by crop type, growth stage, and climate conditions. Typical values range from 0.3 for dormant crops to 1.3 for certain growth stages.
Evapotranspiration Results
Reference Evapotranspiration (ET₀)
Crop Water Requirement Comparison
| Crop Type | Kc (Coefficient) | ETc (mm/day) | Daily Water (m³/ha) | Growth Stage |
|---|
Water Requirement Analysis
FAO Penman-Monteith Formula
ET₀ = [0.408Δ(Rₙ – G) + γ(900/(T+273))u₂(eₛ – eₐ)] / [Δ + γ(1 + 0.34u₂)]
The FAO Penman-Monteith equation is the standard method for calculating reference evapotranspiration (ET₀). It combines energy balance and aerodynamic principles to estimate water loss from a reference surface.
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