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AgriMet Crop Coefficients

AgriMet estimates crop evapotranspiration (ETc) by first modeling reference evapotranspiration (ETr) from observed weather conditions at each weather station. AgriMet uses alfalfa as its reference crop. This reference ET is then multiplied by a crop coefficient (Kc) that varies through the season depending on the growth stage of the crop. Crop coefficients, from plant emergence to termination, define a growth curve know as a crop curve . The product of reference ET times the crop coefficient is the estimated crop specific consumptive use:

ETc = ETr * Kc

For more information on crop coefficients, see About Crop Curves . For information on specific crop coefficients, click on the links below. Note that these crop coefficients are for use with Alfalfa Reference (Tall Crop) ET.

All Crop Coefficients (Text File)

Alfalfa Peak (Actively growing mature, uncut alfalfa)
Alfalfa Mean (85% of Peak, takes seasonal cuttings into account)
Alfalfa Hay Peak (Actively growing mature, uncut alfalfa hay)(75% alfalfa/25% grass)
Alfalfa Hay Mean (85% of Peak, takes seasonal cuttings into account)(75% alfalfa/25% grass)
Apples
Asparagus
Beans (Snap beans, pink beans, and lentils)
Beets
Bluegrass Seed (Established)
Bluegrass Seed (Fall Seeded)
Blueberries
Brocolli
Cabbage
Concord Grapes
Cherries (East of the Cascades, NO cover crop between trees)
Cherries (East of the Cascades, WITH cover crop between trees)
Corn (Field and Sweet Corn)
Cranberries
Carrot Seed (Full Irrigation)
Carrot Seed (Reduced Irrigation)
Grass Hay (Peak) (Actively growing mature, uncut hay)
Grass Hay (Mean) (Average annual water use with 3 cuttings)
Hops
Lawn (Lawn and Turf)
Lettuce
Melons
New Peppermint
Onion/Garlic
Pasture
Peas
Pears
Poplar : First Year
Poplar : Second Year
Poplar : Third and Subsequent Years
Potatoes (Russet)
Potatoes (Shepody)
Peppermint
Rapeseed (Canola)
Rapeseed - Fall Plant (Canola)
Safflower
Spearmint
Spring Grain
Strawberries
Trailing Berries (Raspberry, Blackberry)
Winter Grain
Wine Grapes