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Crop Water Use


Crop water use information is pulled from the AgriMet website. AgriMet uses site specific weather data to estimate evapotranspiration (ET, or crop water use) for crops grown in the vicinity of each weather station. AgriMet uses the 1982 Kimberly-Penman ET model developed by the USDA Agricultural Research Service in Kimberly, Idaho to compute daily reference ET at each station. AgriMet uses alfalfa as the reference crop. Specific crop coefficients are then used to compute crop specific ET based on the alfalfa reference ET. These crop coefficients vary throughout the growing season based on the plant growth stage. The crop coefficients are tied to the actual plant growth stage by three dates: Start, Cover, and Terminate dates. Start dates are the beginning of vegetative growth in the spring for perennial crops or the emergence date for row crops. Cover dates are typically when plants reach full foliage. Termination dates are defined by harvest, frost, or dormancy.

What is Evapotranspiration (ET)?

Water from precipitation or irrigation can enter the soil where it comes into contact with the crop root system.


Evapotranspiration is the water removed from the soil, by soil evaporation and plant transpiration.

We use the LEGROW site for the Southern Columbia Basin. Tri-Cities, Burbank, Eltopia, Ringold, Mesa. There are other sites available on the AgriMet website.


Click here for the current LEGROW ET Chart.


For more information, please contact the Franklin Conservation District at: (509) 416-0440


More sites are available from the AgriMet website that may suit your location better.

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