Dana Christel and Vicki Morrone
As the perennial grain Kernza® continues to be featured in agricultural news articles and press releases, the level of interest in this new crop for both buyers and farmers continues to grow. This is especially true given the recent announcement of General Mills’ plans to incorporate Kernza® grain into cereals and snack bars under their brand, Cascadian Farm Organic. Kernza® is the trademarked name given to seed or grain harvested from a perennial forage grass called intermediate wheatgrass. Efforts to domesticate intermediate wheatgrass into a grain crop were initiated in the 1980s by the Rodale Institute and taken over by The Land Institute in 2003. What exactly does it take to grow this hip, new grain with long roots and a wild past? Of course there are differences in the management of this crop compared to an annual. This article offers some answers to agronomic questions from the viewpoints of three farmers in the Midwest, each with varying levels of growing experiences with this new crop. We interviewed each of them on their approaches to planting, managing and harvesting intermediate wheatgrass for grain.
University researchers and farmers have shown that intermediate wheatgrass can be planted using a standard grain drill. Carmen Fernholz, an organic farmer in Madison, Minnesota, first planted two acres of this crop in 2011. When asked about the planting process he said, “Planting really wasn’t a challenge. I used my regular grain drill. I had a pretty good, firm seed bed and planted the seed very, very shallow- not even a half inch deep, almost like planting prairie grass. It stayed fairly dry that fall, but eventually we did get germination and emergence. Then the next spring, the stand really took off and it gets thicker and thicker every year.” Randy Hampshire farms in Kingston, Michigan and just planted intermediate wheatgrass this past fall using his Oliver grain drill. He explained, “I planted it on two acres on top of a hill along with buckwheat. I wanted a nurse crop to come up with it and that seemed to work beautifully. I seeded with a conventional grain drill. I just had to figure out which setting to put it on. I started using the setting for grass seed but it ended up being a little too big for that one so I went the next size down and that one worked better”. Using nurse crops on an organic farm helps reduce weed challenges as the crop becomes established. Buckwheat dies with a killing frost so there is relatively little management needed for termination and the dead plants act as a mulch around the young intermediate wheatgrass plants, reducing weeds in the field.
Farmer Jack Erisman, located in Pana, Illinois planted intermediate wheatgrass in 2011 as Fernholz did. He planted ninehis past fall he planted 18 more acres of the latest generation of intermediate wheatgrass seed using an air seeder that he often uses for other small seeded crops. University researchers have been recommending that farmers plant intermediate wheatgrass in rows, though the ideal row spacing is still to be determined. Erisman chose an alternative approach for spacing; “Everybody has been talking about rows and cultivation and it just seemed incongruous to me to take something as a perennial and then go and cultivate it. So, we’ve always just solid seeded it.” Planting date varied among each of these farmers, but each of them planted in the fall around September. Dr. Jacob Jungers of the University of Minnesota states they’ve found this timing is the best time to plant, and that establishment is better in the fall than in the spring due to less weed competition.
Fertilizer inputs also varied among farmers. In the 5+ years intermediate wheatgrass has been growing on Fernholz’s farm he has applied hog manure once during the second year at a rate of 65 lb N/acre. Erisman followed a similar approach and applied composted cattle bedding at a rate of 1-1.5 t/acre. Hampshire stated he had to adjust for some low fertility in the field where his Kernza was planted this fall and applied 2 tons of dairy compost per acre before planting.
From talking with different researchers and these farmers, I’ve gotten the impression that weeds in intermediate wheatgrass stands have not been a big issue for the most part if they manage to plant early enough in the fall to allow good crop establishment. Dr. Jungers noted that in most of his conversations with organic farmers, they are not all that concerned with weeds. Sandra Wayman, a researcher from Cornell University studying intermediate wheatgrass has not observed many issues with weeds in their experimental plots either. When asked about weeds, Erisman said, “In the first year when we didn’t have a great stand, there was some red clover and other weeds popping up, but by the second year, the wheatgrass rhizomes had spread, and it seems like they can choke out almost anything.”
Harvesting intermediate wheatgrass grain, or Kernza® is one of the aspects of the crop that remains a challenge. Though seed size continues to increase, it is still a very small seed. As of now, the University of Minnesota (UMN) suggests two approaches to the grain harvest: Direct combining or swathing followed by combining. Fernholz explained the challenge in more detail. He said, “What I was made aware of is that the intermediate wheatgrass seed head ripens from the tip down, and so you have to wait quite a while before those bottom kernels are ripe. But then you start getting some shattering and the grain starts dropping out. So, with the University of Minnesota, we’re trying to determine the optimal time to harvest.” Fernholz windrowed the intermediate wheatgrass stand on his plot and then combined it. “If you can cut it a little bit on the green side, put it in windrows and then let it dry down in windrows, then we can harvest more seed. Having to wait until the bottom kernels are ripe exposes you to weather conditions that coud cause more shattering,” he said. He’s also been working with UMN to figure out the proper settings of the combine; “How to adjust the threshing mechanism in the combine can be a challenge because the seed is so light and it does have a hull on it, so how to adjust wind and sieves and everything can be a challenge. We were just trying to determine those kinds of adjustments as well.”
Erisman said he used a standard combine using the standard setting for grass seed, and his thoughts echoed Fernholz regarding the way intermediate wheatgrass ripens and addressed it by cleaning it right away. “One thing we did do is have it cleaned fairly soon. In my short experience, you can harvest it at different stages. It doesn’t necessarily ripen as evenly as you thought it might. So when you harvest you might have some green in the grain, so you want to clean it pretty quickly,” said Erisman.
Grain yields still seem to vary quite a bit. The average grain yield is around 500 lb/acre, but, as with any crop, Kernza® yields are dependent on weather. Erisman noted that his first grain year, 2012, there was almost no yield to speak of due to drought. In 2013 and 2014 he said they got more rain and had a better grain crop, but yields were only around 300 lb/acre. However, Dr. Jungers has said there is potential for Kernza® yields of 1500 lb/acre, and points out that yields are increasing with every plant breeding cycle and as we learn more about the agronomics.
Jungers said they’ve observed grain yields fall off after the third year of growth as corroborated by both Fernholz and Erisman. University of Minnesota has some different experiments considering ways to revitalize grain production in older intermediate wheatgrass stands. In 2016, Fernholz’s fields had low yields and decided it was not worth harvesting. So he tried something. “The intermediate wheatgrass has really gotten itself sodded in. So grain production this past year was virtually nothing. So, what I did this fall was I went through the plot with a chisel plow and stripped it to see if it would help to thin out some of the tillers to stimulate regrowth and rejuvenate grain production.” Erisman tried another approach to revitalize his 2011 stand. “We interseeded red clover into the old stand, because I’ve noticed with the old stand that the seed production isn’t as good and it has become very rootbound. I didn’t want to disturb the soil too much, so we went out with a no-till drill and set the coulters as deep as we could, just to cut the roots while seeding the clover at 10-11 lb/acre on the surface. The red clover is doing very well and it doesn’t seem to have hurt the wheatgrass at all. But we’ll see if we get any grain stimulation from that.” The expectation is that the clover will fix some nitrogen and its roots will loosen the soil.
Words of Advice
Fernholz, Hampshire, and Erisman are cautiously optimistic that this crop may become a viable contributor to their crop portfolio and improve soil health on their farms. They continue to participate in research on their farm and share their results and experiences with researchers and other farmers. Being two of the more experienced Kernza growers, I asked Fernholz and Erisman what they’d tell a farmer who is either new to growing Kernza or interested in trying to grow it. Here are their words of advice:
“Well my first piece of advice would be, I wouldn’t bet the farm on it yet.”
“Know that you have a market if you’re planning on generating some revenue.”
“Really be aware of the agronomic characteristics of the crop itself. Know that its three years and you’re going to have to do something with it other than harvesting a cash crop.”
“Don’t overcomplicate it.”
Agronomic research to improve production of intermediate wheatgrass is ongoing, and several new efforts have been initiated in the last year. The University of Minnesota and Michigan State University recently began a two-year research project funded by a Ceres Trust grant that will study the effects of grazing on the intermediate wheat grass and assessing Kernza® yield and quality. The research aims to test if the crop can offer dual use: grain for flour or brewing and pasture for dairy cows. Trials were set up in the fall of 2016 on University and farmer’s land. Here in Michigan, intermediate wheatgrass was planted at Kellogg Biological Station and at Hampshire Farms in Kingston, MI and is slowly waking up from its winter dormancy. We will be putting dairy cows on it this year on some plots and other plots we will allow to set seed for harvest. Watch for information regarding upcoming field days at one or both locations this summer. These events will offer a place to learn more about our findings and possible ways to grow intermediate wheatgrass for grain and forage!