Comparison of irrigation systems shows promise for hay growers in water-depleted northern Lake County

A sprinkler system in an alfalfa field in Lake County, Oregon.

The environment in the Fort Rock-Christmas Lake Valley basin and Silver Lake region of Lake County is unique because of its dry climate, hot summer days, cool nights and soil type, making it one of the best alfalfa-growing regions in the western United States. Much of the hay produced is of supreme quality and is highly desirable, especially for the export market.

Northern Lake County produces most of the irrigated alfalfa hay in the Fort Rock-Christmas Lake Valley basin of central Oregon and is a mainstay of the local economy with over $90 million in sales. With little to no surface water available for irrigation, alfalfa production relies heavily on groundwater, which has decreased because of ongoing drought. Water conservation is essential for the preservation of the community.

In response, concerned alfalfa growers have asked for an investigation of irrigation systems that will conserve water resources and preserve the aquafer for the future. At the request of the Lake County Hay Growers Association, Oregon State University Extension Service conducted a pilot on-farm trial to determine if forage dry matter was affected by low-elevation sprinkler systems compared to mid-elevation sprinklers.

Fresh forage samples were collected for dry matter analysis and hay samples were used to determine any changes in hay quality. Dry matter, the forage left after water is removed, is an indicator of the amount of nutrients that can be found in the forage. When measuring fresh forage, dry matter analysis can give a good estimate of yield.

The study showed changes in dry matter yield when comparing the two systems prior to the third harvest and illustrated a difference in forage quality.

The results of the dry matter analysis showed there was an estimated yield increase in the low-elevation sprinkler system by about 10% when compared to the mid-elevation system prior to the third cutting. A 10% increase at today’s average supreme quality hay prices, which is $400 a ton, would increase cash input by $130 a ton.

Because the pilot study showed promise, another more robust field trial will be conducted in 2023 at the request of hay growers in northern Lake County.