Resurrecting ‘Denali’ Alfalfa in Alaska

Here in the Last Frontier state, alfalfa is an expensive commodity. It’s a hearty, nutritious feed for livestock and horses, though Alaskans often pay nearly double the price of regular grass hay for alfalfa, due to high transportation costs to ship it from the Lower 48 states.

“Alfalfa costs about $800 - $1,000 a ton in Alaska,” said Casey Dinkel, agronomist with the Plant Materials Center (PMC) in Palmer. “Grass hay may run you about $400 to $600 a ton, and generally alfalfa costs nearly double that.”

Producing alfalfa in-state would save money for farmers and landowners, but growing it here is challenging. Typical winter-hardy alfalfa varieties don’t survive in Alaska due to long, cold winters with sub-zero temperatures. The freezing ground can cause the tap root to sever and deplete the plants' carbohydrate food reserves, ultimately killing it.

However, there's a unique variety of alfalfa designed for Alaska's climate: the ‘Denali’ alfalfa variety, developed in the 1970’s at the University of Alaska Fairbanks.

The goal was to create a species of alfalfa that could withstand harsh winters by establishing a more fibrous root system with a reduced tap root to prevent severing during sub-zero temperatures. ‘Denali’ alfalfa is a variegated variety selected from three populations of Siberian germplasms.

‘Denali’ alfalfa has been produced across the state on a small scale throughout the '70s and '80s, though historically there has not been a large-scale harvest...until now.

On July 2, 2020, staff at the PMC harvested 1.5 tons per acre of alfalfa of alfalfa on a 2.2 acre field. Later on Aug. 14, the crew harvested a second cut of 1.5 tons per acre. The first cut made 183 small square bales and the second cut made 8 large round bales. The size and scale of this harvest is making history in Alaska agriculture.

Partnerships Make it Happen

The USDA Natural Resources Conservation Service partnered with the Alaska Plant Materials Center to make it happen. These two agencies came together through a partnership agreement to fund, plan and implement a 'Denali' alfalfa field trial.

The field trial objective was to propagate sufficient seed in research trials that can be evaluated for nutrient composition, yield production, winter hardiness, and pesticide resistance. There is also potential to use alfalfa as a conservation benefit for soil health.

"Perennial crops like alfalfa keep a living root in the soil all year round, which is a one of NRCS's recommended management principles for soil health," said State Soil Scientist Cory Cole. "Living roots provide a source of food for the microbial community. They increase water infiltration, reduce compaction and improve organic matter."

According to Dinkel, it took three years of careful management and a lot of patience to achieve a harvestable crop.

Here's a quick summary of how the process went...

Year 1

The seeds were planted in early June of 2018. As the alfalfa started to grow, Dinkel noticed that nearly half of the field was dominated by weeds that threatened to choke out the alfalfa. That summer and fall, he mowed the alfalfa high to prevent any weeds from producing seeds, while letting ‘Denali’ establish a substantial root system to survive the upcoming winter. No alfalfa was harvested for forage in year one.

“By mowing it high that first year, the alfalfa could direct more of its energy into its root system instead of producing new growth and seeds.” Dinkel said. “Having a deep, extensive root network is critical to surviving the winter. Plus, the snow cover provides insulation to protect the soil.”

Year 2

As spring rolled around, the alfalfa grew up pretty well, still with a lot of weeds but not quite as many as the first year. Throughout the summer, Dinkel sprayed herbicide treatments to kill the weeds. The herbicide killed the weeds, but it also caused damage to the alfalfa, stunting its growth for the remainder of the summer.

“Our cold soils do not allow for most herbicides to break down as fast as needed or designed,” Dinkel said. “This residual herbicide can cause damage to a commodity crop in Alaska, where it would not in warmer regions.”

In the fall, Dinkel mowed six inches off the top of the alfalfa, leaving a stand of about 12 inches to withstand the winter. An application of fertilizer was also added to help the alfalfa field store nutrients for the long, cold winter ahead.

Year 3

And finally, as the snows of 2020 melted away, the alfalfa grew again – this time with very few weeds. Dinkel estimated this crop was about 97 percent alfalfa and only three percent weeds. When July rolled around, it was time to harvest. Finally, after three years – a crop yield.

After the first harvest, an application of fertilizer was immediately added to increase biomass and root production.

So, what does this mean for the future of alfalfa in Alaska?

The PMC and NRCS are interested in partnering with farmers and landowners who are interested in production on 3 to 5 acres. The goal is to take lessons learned from the PMC/NRCS trial and apply them on a larger, more commercial scale to better calculate the agronomic inputs and savings.

Dinkel is hopeful that farmers could replicate the PMC trial and establish a harvestable crop in less than two years.

Efforts are already underway in North Pole/Fairbanks, Kenny Lake/Copper Center, and Palmer/Wasilla. Interested landowners are encouraged to contact the PMC for more information.

‘Denali’ alfalfa seed is not available commercially and limited supplies are available at the PMC.

Courtesy of the USDA Natural Resources Conservation Service Alaska office