To Matthew Ott, three words could make all the difference as to whether farming systems that protect the soil year-round in Minnesota become a consistent agricultural presence in the state. “For me, the most exciting thing is to be able to use the term, ‘cash cover crops,’ ” says the University of Minnesota graduate student. “It’s combining environmental and financial sustainability, and you need both to have true sustainability.”
Ott is part of an innovative U of M research initiative that is out to prove environmental sustainability and financial viability can go hand-in-hand.
The Forever Green Agriculture Initiative is an ambitious, multidisciplinary approach to getting more continuous living cover on the land in that “brown period” when regular cash crops aren’t growing. That’s a big deal, considering that Minnesota’s top row crops, corn and soybeans, cover the land for only a few months out of the year. That means for six months or more, around half of Minnesota lacks any living roots or even basic vegetative ground cover, creating a long bare season during which the land is particularly prone to being washed and blown away. The most recent sign that this lack of cover is taking a toll on the land is all of the "snirt" that stained Minnesota snowbanks this past winter.
Forever Green funding provided by the Minnesota Legislature in 2014 (see sidebar to the right) has moved the initiative ahead significantly in just the past several months, according to Michael Schmitt, associate dean of the College of Food, Agricultural and Natural Resource Sciences. Schmitt says legislative funding has made possible innovative research on, among other things, pennycress, intermediate wheatgrass, kura clover, hybrid hazelnuts and camelina.
Just as importantly, says Schmitt, it has also given numerous graduate students invaluable experience in doing cutting-edge agricultural research, helping develop a new generation of agricultural scientists.
Cover Cropping's Public Service
Studies throughout the Midwest have shown that growing low-value cover crops such as small grains before and after the main cash crop season can dramatically cut erosion and runoff while building overall soil health.
“The literature is very robust on the ecosystem services provided by cover crops,” says U of M graduate student and Forever Green researcher Michelle Dobbratz. She’s seen some of these services firsthand through her research integrating kura clover as a “living mulch” into row crop systems. A living mulch grows between the rows of crops like corn for several years in a row, providing a year-round companion cover while building soil structure. Dobbratz said she has already observed how living mulches help fields she studies soak up heavy rains during storm events, while neighboring unmulched crop fields are flooded.
“Farmers are increasingly demanding risk management and resiliency from their fields,” says Dobbratz.
And according to surveys and anecdotal evidence, farmers across the country are finding that cover crops can build the kind of soil resiliency that helps cash crops better weather extreme conditions such as drought while reducing the need for expensive commercial fertilizers.
But such economic benefits are not as immediate and direct as bin-busting yields. Integrating cover crops into a corn-soybean system costs money and can be logistically tricky. In states like Minnesota, conditions often make for a narrow window of opportunity for planting and establishing something on the edges of a standard growing season.
That’s why the Forever Green initiative is taking a multi-faceted approach to developing systems that provide the land protection 12 months out of the year, according to Don Wyse, a U of M plant scientist who is helping lead the initiative. Not only is Forever Green trying to develop soil-friendly plant varieties that can grow and produce well "outside" of the traditional growing season, but working to figure out how to develop marketable products from cover crops, in effect giving farmers an economic incentive to plant what up until now has been seen as a economically “useless” class of commodities.
For example, one of the crops Forever Green is experimenting with is field pennycress, an extremely winter-hardy member of the mustard family that provides soil protection, uses up excess nitrogen, cuts erosion and suppresses weeds in the spring. Actually, there are numerous cover crops that provide such services. But pennycress also produces an oilseed that can be used in biofuel, among other things, and a processing byproduct can be used for animal feed.
According to the Massachusetts Institute of Technology, pennycress could potentially be grown on over 40 million U.S. corn and soybean acres without displacing those crops. That amount of acreage would yield up to six billion gallons of oil that could be converted to biodiesel—that represents roughly 15 percent of the 40 billion gallons or diesel consumed annually in this country.
And because pennycress begins flowering in April or May when honeybee colonies are returning to the Upper Midwest, it can provide critical food for domesticated and wild pollinators at a time when other flowers are hard to come by.
Wyse describes a scenario where a farmer could plant pennycress in the fall after corn harvest, allowing it to overwinter. The idea is to create a continuous living cover on the land through a kind of plant “relay” system where the growing seasons of two crops overlap—as one crop is winding down for the season, another is just getting started. Forever Green trials have shown soybeans can be planted into pennycress in May and then the cover crop’s oilseed is harvested in June, making way for the soybeans to grow the rest of the season.
“So that extends both seasons,” says Wyse.
That overlap can not only produce dividends for a well-protected soil, but it can increase the land’s ability to produce profitability 12 months out of the year, something scientists call "temporal intensification." Studies show that growing pennycress and soybeans together increases by 40 percent an acre’s overall production of oilseeds (60 bushels per acre of soybeans, 40 bushels of pennycress, for example). One estimate is that pennycress can add an extra $300 of per-acre profit to a soybean field.
“And so instead of just planting a cover crop for the long-term environmental benefits, the farmer can have some rapidly realized economic returns,” says Kayla Altendorf, a graduate student working on a pennycress breeding project.
Forever Green researchers are benefiting from recent major strides made in identifying and selecting which parts of the plant DNA can produce desired characteristics. When there are multiple genes controlling a certain trait in a plant, it’s not clear the level of dominance each trait has when cross-breeding takes place. But mapping the genome of a plant can help pinpoint what best combinations will produce the desired outcome. Fortunately, pennycress and camelina are very closely related to arabidopsis, the first plant to have its entire genome sequenced.
Kevin Dorn, a U of M doctoral student doing genomic research on pennycress, says just a decade ago it would have cost tens of millions of dollars to use DNA sequencing to improve a plant species like pennycress. Dorn and others, using pennycress they harvested from a roadside south of the Twin Cities, recently mapped the plant's genome for around $75,000.
According to a 2014 article in the journal Plant Science, affordable genome sequencing technologies and advanced breeding techniques have reduced the time scale it takes to domesticate a new crop from hundreds or thousands of years, to decades. The map Dorn and his team created is helping make it possible to select varieties that, for example, flower earlier or don’t produce seed pods that shatter as easily during harvest (a common problem with pennycress). Once these traits are identified, then plants can be bred and propagated through traditional breeding methods, which means researchers don’t have to rely on controversial genetic engineering technologies to produce the next generation of plants.
“We can do in eight years what you may have been able to do in classical breeding in maybe 50 to 100,” says Wyse. “Give us 10 years of solid funding and this Forever Green group can make a difference.”
And consistent financial support is critical if Forever Green is to advance to the point where farmers can benefit from it, says Wyse. He adds that more cropping trials need to be established in different parts of the state so that comparisons can be made between soils, weather conditions and topography.
Another reason Forever Green requires long-term investment is because it’s not just taking a narrow, agronomic view of how to improve cover cropping. How can the market value match the environmental value of these crops? Forever Green proposes doing this by developing incubators across the state that would coordinate the technological, economic and even policy innovations needed to make alternative crops a consistent part of the farming picture.
These incubators could help overcome the “chicken or the egg” barriers that often plague innovations in agriculture. What incentive do farmers have to plant a new crop if there is no market for it? And even if there is a market, what if there are no processing and transportation systems available to get the product from the field to the end user?
These are big-picture questions that require working across disciplines that cover everything from plant genetics and breeding to mechanical engineering of tillage and harvesting equipment. Even food science and marketing have to be part of the picture, says Wyse.
And that’s possibly the most exciting aspect of Forever Green— land grant university research can often suffer from the “silo effect,” where scientists working in different, but related, disciplines don’t know what’s going on in the next lab or test plot. Such a myopic way of operating can be particularly keen as competition for limited funding increases.
But several of the researchers working on the Forever Green initiative describe how the interdisciplinary nature of the effort is allowing them to shorten significantly the time required to get basic science to the practical, on-the-farm stage. Dobbratz, the kura clover researcher, says such border crossing is key if it’s to help solve the “grand challenge” facing society: how to feed people sustainably.
“You can’t just exist in your own little lab anymore,” she says. “I think our team is keenly aware of the need for boundary work—that is the need for working across different disciplines. None of us have a hero complex—we’re aware that we’re one tiny piece of a larger puzzle.”
Brian DeVore is the editor of the Land Stewardship Letter.