Hay field irrigation
How much water per acre for grass hay in central Oregon
Deschutes County Oregon
If you type in "Agrimet" into a search engine, and once there, you click on crop water use program... click on Oregon, then click on the site in Central Oregon (Bend, Powell Butte, or Madras) that most closely fits your site. This years total water use by the different crops, including grass hay, is listed. Use the lesser amount of the two listed which takes in account the down time for harvests. Anyway that will give you amount of water that grass hay crop would use under ideal conditions, based on daily weather. This is evapo-transpiration or ET - the amount of water that plants transpired during growth and the amount of water evaporated on a daily basis. You would divide this number by the efficiency of your irrigation system (0.70 for wheel line as an example) to give the amount of water you would have had to apply. You would also go into the archived years if you want data for different years. If you have questions, please call me at 541-447-6228 (OSU Crook County Extension Office).
Area Extension Agronomist
OSU Extension Service