A national agricultural research initiative aims to promote soil health through the development and adoption of new cover crops across the U.S.
Beneath the surface of civilization lives another world, a microscopic one filled with fungi and bacteria so tiny that millions of them can fit in one teaspoon.
Many of these microbes make their homes along the underground highways of plant roots. They act as tollbooths, helping the roots take in water and nutrients from the soil in exchange for food and shelter. When the roots are gone, the microbes suffer. When microbes suffer, eventually the soil deteriorates.
Soil sickness is not obvious at first. But over time, mediocre soils increasingly lose their ability to hold water. They become vulnerable to wind, which carries them away in storms reminiscent of the Dust Bowl. They lose their natural fertility and ability to capture and store carbon.
Healthy soils hold the power to solve many of farmers' and ranchers' greatest challenges. But how do farmers and ranchers rejuvenate their lands? One way is to cover the soil in plants year-round with a practice called cover cropping. And today's agricultural producers are increasingly interested in the historical practice.
To Develop New Cover Crop Solutions
Jimmy Emmons stumbled upon the concept of cover cropping at a farming conference about seven years ago.
The third-generation farmer and rancher from Leedey, Oklahoma, had been searching for ways to improve his wheat, alfalfa and canola yields. Regardless of how much fertilizer Emmons applied or how much rain the land received, his production had plateaued.
At the conference, a farmer from central Ohio talked about how he had transformed his land by planting cover crops. After harvesting his primary crop, like corn or soybeans, this farmer planted a crop to grow during the season when the land would typically lie bare. Its primary purpose was to improve soil health.
"I thought, 'Man, if I could do that here in Oklahoma, that would be great,'" Emmons says.
There are costs associated with planting any crop. There's seed to buy and machinery to maintain. The risk can seem high when the crop planted is one that typically is not harvested and sold.
But Emmons found that the practice started paying off within three to four years. Today, he credits cover crops, alongside no-till and rotational grazing, with helping reduce his fuel costs by two-thirds and his fertilizer costs by half. As a result of reducing his need for inputs, Emmons has also reduced the potential for nitrogen and phosphorus runoff into nearby streams.
Based on a national farmer survey funded by the U.S. Department of Agriculture, cover crop users in 2012 were planting just more than 200 acres per farm. By 2016, that number had doubled. Still, the estimated 17 million acres of cover crops in the U.S. today represent just a small fraction of the 250 million acres of row crop fields in the U.S. as of the most recent census, from 2012.
In March 2017, the Foundation for Food and Agriculture Research and the Noble Research Institute announced a $6.6 million national research initiative to promote soil health through the development and adoption of new cover crops across the U.S.
Jim Johnson, a soils and crops consultant, (right) explains how cover crops can help improve soil health to a group of Noble Board of Directors members, most of whom are descendants of Lloyd Noble, during a tour in 2017. Johnson has been testing various species to see how they perform in the Southern Great Plains.
The project will address some of farmers' practical questions: Which is the best type of cover to use for which field? How do short-term costs compare with long-term gain? When is the best time to kill the cover crop? How do cover crops affect soil moisture?
"There's not going to be one answer," says Twain Butler, Ph.D., forage agronomist at the Noble Research Institute and project leader. "It's going to be different in Oklahoma and this part of the country than elsewhere."
To answer these questions across the nation, field studies will be conducted at five strategic sites: Maryland for the Northeast, North Carolina for the Southeast, Oklahoma for the Southern Plains, Nebraska for the Northern Plains, and Missouri for the Midwest.
Most species planted as cover crops today were bred for other purposes, like forage and grain production, rather than to maximize conservation traits. In developing new varieties for cover crop use, the researchers will look to bring out plants' natural abilities to develop deep roots and to grow at times that better coordinate with primary crops' growing seasons. Species of interest include small grains (wheat, rye, oat and triticale), annual legumes (hairy vetch, winter peas and clovers) and brassicas (turnips, radishes, kale and mustards).
The network of researchers will also work with farmers and ranchers to better understand what is needed in the field as well as with seed companies to expand effective options on the market.
"Our goal is simple: to get new cover crop solutions into the hands of those who use them or will be using them," Butler says.
On a Mission to Cover the Country
Farmers are increasingly interested in growing cover crops. As the name suggests, cover crops “cover” ground that would otherwise lie bare. While these crops do not usually become food for us to eat, farmers can use cover crops to boost soil health, improve water quality and sequester carbon. In some cases, they can be grazed by livestock.
Cover Crop Benefits
When plants (and their roots) grow, generally speaking, the land is better able to retain water and the soil is less likely to be blown or washed away. Cover crops also feed the microscopic creatures that live in soil. In turn, these microbes help future crops grow healthy and strong.
Depending on the situation, cover crops can:
- Increase crop yields.
- Fix nitrogen.
- Sequester carbon.
- Reduce pollution.
- Reduce the need for
- Attract pollinators.
- Slow or reduce erosion.
- Increase organic matter in the soil.
- Control plant pests, diseases and weeds.
- Increase biodiversity.
- Conserve water quality.
- Provide seasonal habitat for wildlife.
Cover Crop Research at Noble
Farmers have many questions about which species to choose as cover crops and how to successfully implement the practice on their land. Currently, most species planted as cover crops were bred for other purposes, like forage or grain production, rather than to maximize conservation traits. The best species to plant will vary from location to location. The Noble Research Institute is part of several projects to help get new solutions into the hands of those who use or will be using cover crops:
Developing New Cover Crop Cultivars
In 2017, the Noble Research Institute and the Foundation for Food and Agriculture Research (FFAR) launched a $6.6 million national research initiative made possible by a $2.2 million grant from FFAR.
The initiative seeks to promote soil health through the development and adoption of new cover crops across the U.S. Species of interest include small grains (wheat, rye, oat and triticale), annual legumes (hairy vetch, winter peas and clovers) and brassicas (turnips, radishes, kale and mustards). Field studies are being conducted in Maryland, North Carolina, Oklahoma, Nebraska and Missouri.
- Xuefeng Ma, Ph.D., assistant professor, is developing rye, triticale and oat cultivars specifically for dual use as cover and forage. He is also developing genomic resources for small grains.
- Suresh Bhamidimarri, Ph.D., assistant professor, is developing hairy vetch and crimson clover cultivars. He is also developing genomic resources for annual legumes.
- Zengyu Wang, Ph.D., director of core research and transformation, is developing genome editing tools to identify specific genes controlling hard seed in hairy vetch.
- Twain Butler, Ph.D., research agronomist, serves as project manager.
Learn more at noble.org/ffar.
Evaluating Species for the Southern Great Plains
In 2014, Jim Johnson, soils and crops consultant, began evaluating the local adaptation of a broad suite of nearly 100 common and exotic species used as cover crops. By 2017, he and partners had completed 18 site years of observation.
Find out what Johnson has learned at noble.org/the-great-cover-crop-test.
Watch the videos at bit.ly/cover-crop-playlist
Cover Crops and Microbial Diversity
Kelly Craven, Ph.D., associate professor of microbial symbiology, is working with James Rogers, Ph.D., to better understand the impacts of cover cropping and tillage on microbial communities and ultimately the health of Oklahoma soils.
Learn more at noble.org/cover-crops-tillage.
Find the latest cover crop information at noble.org/cover-crops.