Promoting Conservation and Wise Use of Natural Resources

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 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 web site.

Estimated crop water use for July 20, 2010

Crop	Start Date	Past 7D Avg	Cur. Daily Use	Sum ET YTD	Future 7D Avg.
		Penman ET - Inches
ALFP	311	0.35	0.37	26.54	0.33
ALFM	311	0.30	0.31	23.01	0.28
BLGR	311	0.02	0.00	18.31	0.00
LAWN	311	0.28	0.30	21.77	0.27
WGRN	311	0.03	0.00	21.93	0.00
SRGN	405	0.27	0.27	19.79	0.24
POTS	501	0.31	0.32	17.20	0.28
POTA	510	0.33	0.34	14.36	0.31
POTA	520	0.33	0.34	11.50	0.31
BEAN	520	0.34	0.35	12.73	0.32
FCRN	520	0.32	0.35	9.73	0.32
FCRN	527	0.28	0.31	8.01	0.28
SCRN	525	0.35	0.37	10.10	0.33
ASPA	420	0.28	0.31	13.67	0.28
APPL	425	0.34	0.36	17.40	0.32
ONYN	505	0.35	0.37	14.94	0.33
CGRP	503	0.30	0.31	11.52	0.28
WGRP	505	0.27	0.28	13.62	0.25

AgriMet Site: LEGROW - 5 miles east of Burbank, WA.

For more information, please contact the Franklin Conservation District at: (509) 545-8546, ext. 3

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

Crop Abbreviation Key
ALFP	Alfalfa Peak
ALFM	Alfalfa Mean
BLGR	Bluegrass
LAWN	Lawn
WGRN	Winter Grain
SGRN	Spring Grain
POTS	Potato (Shepody)
POTA	Potato (Russet)
BEAN	Beans
FCRN	Field Corn
FCRN	Field Corn
SCRN	Sweet Corn
ASPA	Asparagus
APPL	Apples
ONYN	Onions
CGRP	Concord Grapes
WGRP	Wine Grapes