Organic Broadcaster


After years of breeding, eco-friendly perennial wheat looks feasible for farmers

By Carmen Fernholz

Today’s Kernza® has a seedhead that is less susceptible to shattering since it matures more evenly than its predecessor. Photo by Carmen Fernholz

When Don Wyse from the University of Minnesota first approached me in 2011 to see if I was interested in growing perennial wheat for research, my immediate response was yes. I was familiar with winter wheat but curious how wheat could be a perennial, which by definition would come back each year without the need for annual seeding. Don was able to secure enough seed for a two-acre plot on my farm—this is how I came to be involved in the development of perennial wheat, better known by its trademark name Kernza.

To talk about perennial wheatgrass it is necessary first to think in terms of natural ecological systems that are self-sustaining, a concept that has for years captivated the imagination of Wes Jackson, the now-retired director and founder of The Land Institute in Salina, Kansas, which has spearheaded the development of Kernza. As Jackson explains, for at least 10,000 years, humans have kept self-sustaining natural ecological systems in a continuous state of disruption in order to feed our populations and avoid famine. This, in a nutshell, is agriculture as we know it.

In the past 40 years, The Land Institute and its partners have been breeding new perennial grain and seed crops and researching ecologically intensified polycultures that mimic natural systems. At the University of Minnesota, the displacement of this now predominant industrial disruptive system of agriculture is moving forward with an initiative called Forever Green. (Read more about the Forever Green Initiative.)

With this background in mind, where is Kernza in its development toward becoming a reliable addition to a farm’s crop rotation while also serving as a continuous living cover?

Kernza is a winter perennial that is best planted in the Upper Midwest in the last few days of August or first days of September. This in itself creates a challenge for many farmers geared to a corn-and-soybean rotation as the harvest dates for those two crops is usually well beyond the optimum planting dates for Kernza. Work continues to more precisely determine the latest planting date that will not inhibit yield potential.

Early On-Farm Research
As I stated above, I was first introduced to Kernza in the late summer of 2011 when Don Wyse gave me enough seed to plant two acres. I proceeded to immediately plant the grain that September in an area on the farm that I could watch and study, not realizing that it would become more than just a one-time venture.

The following growing season of 2012, my two-acre plot had survived nicely through the winter. Having no specific instructions on what to do with it, I eventually windrowed the field of chest-high grain and baled it, resulting in a biomass yield of nearly three tons per acre.

In 2013, the Kernza again came through the winter and was looking like any good winter wheat field as harvest was nearing. With instructions from the University to harvest it as a grain crop, I was in a bit of a quandary. The Kernza had grown very tall—nearly 6 feet at full maturity. At the same time the 6-8-inch seed head was ripening from the top down. By the time the bottom third of the seed head ripened, the top third began to shatter and fall to the ground. In addition, the kernel of grain was about an eighth the size of a regular kernel of wheat but with the seed hull still attached.

These crop characteristics created two harvesting challenges. When would I windrow it to save the highest percentage of grain? And, how would I adjust the threshing mechanism inside the combine to save as much of this lightweight seed as possible from blowing out the back of the combine? My only choice was to cut the wind across the sieves to a minimum, speed up the threshing mechanism to the maximum and adjust the sieves as tight as possible. (I learned this year that the threshing mechanism adjustments are the same whether using an older cylinder machine or a rotary set up in newer combines.) I ended up with lots of material in the combine hopper that year, but was not certain how much was grain and how much was merely chaff.

That determination is still being worked on even today because the seed characteristics are changing over time with ongoing gene selection and breeding. This also makes it impossible to determine official test weights and reliable expected year-to-year yields. Currently, the conversation around yield is strictly in terms of pounds per acre with no officially determined test weight per bushel.

From the beginning, these characteristics of shattering, seedhead maturity, yield loss, and lodging have been the major agronomic challenges faced by the plant scientists developing Kernza.

Recent Kernza Harvest
After several more years of research and data from the original two-acre plot, fast forward to August 2018 when I had enough seed to plant 15 acres of the most recently developed variety from the University of Minnesota. This variety, named MN-Clearwater, has a kernel double in size from the first grain I planted in 2011. It appears to be much less susceptible to seedhead shattering as the seedhead matures and ripens more evenly. It also has decreased stem lodging, a characteristic quite prevalent in earlier plant development.

One lesser challenge is the actual seeding operation. The seed is still very light and fluffy resembling various types of native prairie grass. In order to assure a uniform stand with a seeding rate of approximately 12 to 15 pounds of seed per acre, it works best to use and accurately calibrate a native grass seeder.

We were successful in getting the MN-Clearwater Kernza planted on the last day of August 2018. What needed to be determined yet was the overwintering ability of the grain. In late March 2019, after a cold, harsh winter, the Kernza appeared to have survived quite nicely and began to green up right on time. I was concerned when we received a late 24-inch April snowstorm which resulted in standing water in the field during the snowmelt. I found that, if the grain is still in major dormancy, standing water does not appear to be an issue.

A high percentage of the current interest in Kernza grain appears to be with organic foods and beverages. This means that fertility and weed management issues need to be quantified as much as possible in order to assure a harvestable and marketable food-grade grain. Observing the grain during the 2019 growing season and working with the University of Minnesota, I visited the field quite often taking pictures and noting specific data to send back for discussion and analysis.

The farm crew harvests windrowed Kernza. Photo by Carmen Fernholz

Harvesting Kernza with a stripper head yields higher-quality grain by taking only the grain head and leaving the green stem to be harvested later as forage or bedding. Photo by Carmen Fernholz

Determining the best harvest date became the main concern as the season progressed. We learned in 2019 that the variety we planted can go from too green to ready to harvest in a matter of 3 to 5 days. Knowing this is critical because there is still a small shattering characteristic present. And of concern to organic producers is the fact that the longer a grain crop needs to stand in the field the greater the weed pressure becomes. Weeds don’t stop growing just because the grain is maturing.

A unique characteristic of Kernza is the fact that is ready to harvest when the seed head is ripe atop a grass green stem—totally different than the other small grains farmers are accustomed to growing. This characteristic poses a challenge. Working with the University, I helped oversee three different modes of harvesting the Kernza in 2019.

The first and most common way to harvest organic grains is to windrow the grain to dry out the green stems. The question then arises as to how long do we need to leave it in a swath exposing it to adverse weather conditions that can diminish the grain quality quite quickly. An additional downside to windrowing is the fact that the grain is exposed to another piece of equipment that can cause additional loss of grain through shattering.

A second way of harvesting is to straight cut the grain much like one would harvest other conventional grains. It is much more convenient and time-saving with a single harvest pass that could reduce the grain loss and exposure to unfavorable weather conditions. However, taking in green stems with ripe grain through the combine makes it challenging to harvest a good food-quality grain. It is possible, but requires the grain to stand for a longer period of time in the field, which increases the risk of grain loss from seed shattering.

A third method is the use of a stripper head. A stripper head operates similarly to a straight cut method. However, the stripper head moves through the field and takes only the grain head itself leaving the rest of the plant still standing. From what I have observed, this third option appears to be the most efficient in all aspects, yielding higher-quality grain with minimal field loss. This method also leaves a green stem intact which can then be harvested as forage or cut and dried for animal bedding.

This is how the harvested grain looks directly out of the combine before processing. Photo by Carmen Fernholz

Management Practices
When we compare Kernza to the many other small grains that farmers are growing, general management practices are very similar. Fertility needs are about the same. I have used reasonable applications of liquid hog manure injected ahead of the initial seeding of the grain and then top dressed after each grain harvest. With application rates of 2,000 gallons per acre, this amounts to approximately 75% first-year availability of 79 lbs. nitrogen, 38 lbs. phosphorus, and 68 lbs. potassium.

In an organic system, it appears that weed management in Kernza should be quite good. The concern, however, is what row spacings should the grower use when seeding the crop. Planting in 6-inch row spacings goes a long way in suppressing weeds. However, this row spacing allows for the Kernza to become sod bound sooner, a condition that is the main cause for significant yield loss after the third growing season.

In the end, the most challenging characteristic yet to be overcome is yield decrease after three growing seasons, which seems to be difficult to define with complete certainty. Scientists and researchers are continuing to study the causes and possible remedies. If Kernza is going to be accepted as a viable third crop in a rotation, this yield-decrease phenomenon is significant because economic profitability must be on a par with other crops to assure adaptation across the food system.

Markets, Future
Which brings us to the marketability of Kernza. Throughout its development, what has been necessary is to maintain the delicate balance between supply and demand. Farmers need to know that the grain is a viable crop option and that there is a reliable market. Buyers need to know that there is a longterm, robust supply of product in order to justify investment in research and development.

Currently, there is a very high demand for organic Kernza, but only in limited products. Food scientists at the University and several major food companies continue to explore uses for the grain, finding the environmental benefits of this perennial a positive asset as they move to “greener” product lines. Several craft brewing companies are very interested in limited quantities as well.

Carmen Fernholz is a MOSES Organic Specialist focused on grain production. He and his wife, Sally, own and operate A Frame Farm, a 400-acre certified organic farm in western Minnesota. Carmen will be part of a workshop panel at the 2020 MOSES Conference on research, growing, processing and marketing Kernza.

From the November | December 2019 Issue


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