METEOROLOGY – GROWING EAON & AGRICULTURE CALCULATOR
Irrigation Schedule
A precise tool.
What is the Irrigation Schedule & How does it work?
The Evapotranspiration (ET) method is a widely used technique for determining the amount of water needed by crops. It accounts for both evaporation from the soil surface and transpiration from plant leaves.
Rainfall data is crucial as it reduces the need for irrigation when natural precipitation meets or exceeds the crop’s water requirements.
ET = frac{0.408 times Delta times (R_n – G) + 900 times gamma times u_2 times (e_s – e_a)}{lambda + gamma (1 + 0.34 times u_2)}
var = meaning
ET = Evapotranspiration
Delta = Slope of the saturation vapor pressure curve
R_n = Net radiation at the crop surface
G = Soil heat flux density
gamma = Psychrometric constant
u_2 = Wind speed at 2 meters height
e_s = Saturation vapor pressure at air temperature
e_a = Actual vapor pressure in the atmosphere
lambda = Latent heat of vaporization of water
ET = Evapotranspiration
Delta = Slope of the saturation vapor pressure curve
R_n = Net radiation at the crop surface
G = Soil heat flux density
gamma = Psychrometric constant
u_2 = Wind speed at 2 meters height
e_s = Saturation vapor pressure at air temperature
e_a = Actual vapor pressure in the atmosphere
lambda = Latent heat of vaporization of water
Parameters
Result
β
Frequently Asked Questions
What is Evapotranspiration (ET) in agriculture?
Evapotranspiration is the total amount of water lost from a crop through evaporation from the soil surface and transpiration from plant leaves.
How does rainfall affect irrigation schedules?
Rainfall reduces the need for irrigation when it meets or exceeds the crop’s water requirements as calculated by Evapotranspiration.
What are the key variables in the ET formula?
The key variables include temperature difference (Ξ), net radiation (R_n), soil heat flux (G), psychrometric constant (Ξ³), wind speed at 2 meters (u_2), saturation vapor pressure (e_s), actual vapor pressure (e_a), and latent heat of vaporization (Ξ»).
How do I interpret the result from this calculator?
The result indicates the amount of water, in millimeters, that crops need for irrigation on a particular day.
Can this calculator be used for all types of crops?
Yes, but specific crop coefficients may need to be adjusted based on the type of crop and its growth stage.
What is the significance of wind speed in the ET calculation?
Wind speed affects how quickly water evaporates from the soil surface, influencing the overall irrigation needs.
How often should I update my irrigation schedule using this calculator?
It’s recommended to update the schedule daily or every few days, especially during changing weather conditions.
Results are for informational purposes only and do not constitute professional advice.