BIOLOGY & AGRICULTURE CALCULATOR
Eto Hargreaves Calculator
Calculate potential evapotranspiration using the Hargreaves-Samani method for precise irrigation management.
What is the Eto Hargreaves Calculator & How does it work?
Potential evapotranspiration (ETp) is a measure of the amount of water that would be evaporated from an open water surface and transpired by a well-watered short grass reference crop, assuming sufficient soil moisture.
The Hargreaves-Samani method is a simple empirical model used to estimate ETp based on temperature data. It is particularly useful in regions with limited meteorological data.
ET_p = 0.0023 times (T_{max} + T_{min}) times (T_{max} – T_{min})^{0.5} times sqrt{R_s}
Tmax = Maximum daily temperature (°C)
Tmin = Minimum daily temperature (°C)
Rs = Solar radiation (MJ m⁻² day⁻¹)
Tmin = Minimum daily temperature (°C)
Rs = Solar radiation (MJ m⁻² day⁻¹)
Parameters
Maximum Daily Temperature (°C):
Minimum Daily Temperature (°C):
Solar Radiation (MJ m⁻² day⁻¹):
Potential Evapotranspiration (ETp):—
Frequently Asked Questions
What is the Hargreaves-Samani method?
It’s an empirical model to estimate potential evapotranspiration from temperature data, useful in areas with limited meteorological information.
How do I use this calculator?
Input the maximum and minimum daily temperatures to calculate the potential evapotranspiration using the Hargreaves method.
What units should I use for temperature?
Use degrees Celsius for both maximum and minimum temperatures.
Why is this calculator important in agriculture?
It helps farmers estimate water needs for crops, optimizing irrigation and reducing waste.
What does ETp stand for?
ETp stands for Potential Evapotranspiration, which measures the amount of water that would evaporate from an open surface and be transpired by a crop.
Can this calculator be used in any climate?
While it’s particularly useful in regions with limited data, it can be applied generally but may need adjustments for extreme climates.
What is the reference crop mentioned?
The reference crop is a well-watered short grass, which serves as a standard for estimating evapotranspiration.
Results are for informational purposes only and do not constitute professional advice.