Running Out of Irrigation Water? Find Out What You Can Do From an OSU Agronomist

August 28, 2020
Running Out of Irrigation Water? Find Out What You Can Do From an OSU Agronomist

It's been a long, hot summer with little rain. Reservoirs are extremely low, and naturally occuring flows in the Deschutes River Basin are well below average. Irrigation districts have already lowered allocations to junior irrigators and the persistent lack of water supply is forcing some irrigation districts to shut off early.

The DRC is working toward a better way to manage water that will ensure more water security for farmers while improving flows in the Deschutes River and its tributaries. Water is precious and we need to find the most efficient way to move forward.

Advice for farmers from OSU Extension Agronomist, Mylen Bohle

  • Is part of or all of your farm or ranch running out of water soon?
  • Is your irrigation district shutting down sooner than normal?
  • Want to save some water for next year if your system allows you to do so?

You might consider shutting off water to your grass and alfalfa hay fields and pastures to allow them to go dormant. You'll want to do this right after a harvest, leaving 3-4 inches of minimum growth on the field, whether haying or grazing.

Ideally with no regrowth (the first part of regrowth utilizes stored sugars and carbohydrates from the crown and root). You do not want to wake the plants up right at the end of irrigation season to regrow and then have them go dormant again. Nor do you want to dribble water to these fields every couple of weeks to keep them alive.

Let the plants go dormant. If they have been dormant, and you have a month’s worth of regular watering to revive the plants, and create tillers for next year’s crop, you can do that.

Planting alfalfa, pasture or grass hay fields in the late summer? You want to make sure the new establishing plants will be established enough to go through the winter. If water is cut off the end of September, that could mean no moisture during the month of October. We hope it rains, though.

If you're wondering whether to apply what limited water you might have left to your grass or alfalfa hay fields, apply to your grass. Alfalfa, with its large storage root will suffer through a drought period better. It is always better to have your grass (and alfalfa) hay field going into winter with moisture. Next year’s first cutting hay or grazing is developed in the fall as new tillers and roots are regenerated in the late summer and fall.

Let’s hope for rain, and later, snow.

A number of years ago, the Timothy producing area around Ellensburg, WA was short on water. Many growers dried up their fields in Timothy immediately after harvesting their first cutting. Other producers tried to irrigate with a little bit of water every couple of weeks for the rest of the summer to keep the plants alive. The following year, the fields that lay dormant the previous mid to late summer after first cutting, substantially out-yielded the fields that were watered to keep their plants alive.

Source: OSU Extension, Central Oregon Agriculture E-Newsletter, September/October 2019, pg 4, Mylen Bohle.Additional resources:

About the Author:Mylen Bohle is an OSU Area Extension Agronomist for Central Oregon working out of the OSU Crook County Extension Office in Prineville since 1989. His work has focused on forage (hay and pasture) and cereal (grain, hay and pasture) species, varieties, and soil fertility research and extension of pasture, grazing and irrigation management education through classes, workshops, and field

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An aerial view of a body of water.