About Crop Water Requirement (ETc) & Net Irrigation Calculator
Calculate daily and seasonal crop water requirements based on FAO-56 Penman-Monteith methodology (ETc = ETo * Kc). Includes preloaded crop coefficient (Kc) benchmarks for 13+ agricultural crops across Initial, Mid-Season, and Late growth stages, credits effective rainfall, and factors irrigation application efficiency.
Key Capabilities & Features
- Standard FAO-56 crop evapotranspiration model: ETc = ETo * Kc
- Preloaded crop database: Wheat, Corn/Maize, Rice, Soybean, Cotton, Tomato, Potato, Sugarcane, Alfalfa, and Citrus
- Automated growth stage selection: Initial/Establishment, Mid-Season Peak, and Late/Maturity
- Gross irrigation requirement calculation factoring system efficiency (Drip 90%, Sprinkler 75%, Flood 55%)
How to Use Crop Water Requirement (ETc) & Net Irrigation Calculator
Select Crop & Stage
Choose your crop type and current phenological growth stage to automatically load the verified Kc coefficient.
Enter Reference Evapotranspiration (ETo)
Input your local daily or weekly weather station reference ETo (mm/day or inches/day).
Account for Effective Rainfall
Enter any usable rainfall occurring during the scheduling window to subtract from gross requirement.
View Net & Gross Irrigation Depth
Obtain daily crop ETc, net irrigation requirement, and gross water volume to apply per hectare or acre.
Privacy & In-Browser Execution Guarantee
Crop hydrology schedules run exclusively in your browser without cloud uploads.
Frequently Asked Questions
What is the FAO-56 Kc crop coefficient?
The crop coefficient (Kc) represents the ratio of crop evapotranspiration (ETc) to reference evapotranspiration (ETo) for a well-watered reference grass crop, varying with crop leaf area and canopy development.