Earth is the only planet known to have soil. This mysterious body has complex architecture, reinforced by biological glues exuded from roots, earthworms, bacteria and fungi: a living world underfoot ignored by most humans. Farmers, however, can’t afford to be oblivious. We still have much to learn about the networked ecological community underground, and the ways soil health drives agricultural productivity and resilience. But we are beginning to understand that this ecosystem needs to be conserved, nurtured, and fed.
Planting cover crops to build soil health is growing in popularity among farmers of all types. Cover crops are planted with the goal of providing ecosystem benefits, and not purely harvested yield. These benefits can include reducing compaction, improving water infiltration, preventing erosion, fixing nitrogen, adding organic matter, suppressing weeds, scavenging nitrate, and feeding beneficial microbes. Species vary by soil type and climate. For example, while mainland U.S. farmers may plant vetch or clover for nitrogen, Caribbean farmers use tropical legumes like guandul (pigeon pea), canavalia, crotalaria, and mucuna. Cover crops may also add beauty, pollinator forage, and wildlife habitat. At our farm, flowering buckwheat and clover even play cameo roles in bouquets.
Cover crops are one of the most widely recommended and adopted farm enhancements of both the Natural Resource Conservation Service (NRCS) and Soil and Water Conservation Division (SWCD). Farmers already planting cover crops may be eligible for payments through the NRCS Conservation Stewardship Program (CSP). Even producers trying them for the first time may qualify for cost-share payments through NRCS’s Environmental Quality Incentives Program (EQIP) or their SWCD. Though voluntary and competitive, historically underserved producers such as farmers of color and beginning farmers, can be eligible for higher payment rates and advance payments.
As the growing season winds down, now is a great time to plan for winter covers. Like any management adjustment on the farm, it is important to be clear about your goals for planting a cover crop, and how it will be managed from establishment to termination. Because it is usually secondary to the main crop, understanding timing and cost is key to making the practice worthwhile and successful.
Cover crops come in many flavors: fat daikons, delicate phacelia, towering sorghum, grinning sunflowers, creeping subterranean clover, sturdy southern peas, stately cereal rye. They can work in planting windows from a few midsummer weeks to an overwintered extended jam. They can be planted in “cocktail” mixes or alone, and make a useful addition to the soil health toolkit for farmers at every scale.
Jamie Stallings farms cotton, soybeans, corn, and peanuts in northeastern North Carolina. He grows on 2,300 acres in Perquimans, Pasquotank, Chowan, and Gates counties, and has participated in cover crop trials with NC State University. Stallings plants wheat as a winter cover crop to prevent soil erosion, reduce tillage, retain soil moisture, and control weeds. He says, “The ground we plant peanuts in is sandy, so having a cover crop on that land is especially important.” Stallings started planting cover crops in vulnerable fields to prevent soil loss from winter storms. When he saw the benefits, he incorporated them into the whole operation. Stallings begins seeding wheat around October 15, and in mid-November switches to cereal rye because it will emerge in cooler weather.
At the other end of the scale, Natasha Shipman manages three-fourths of an acre of vegetables for CSA and farmers markets in Western NC. Shipman says, “I use cover cropping two different ways. In summertime, if there’s an area I want to let rest, I plant a mix of species, usually buckwheat, sunn hemp, and sorghum or millet. Buckwheat is great for pollinators. In winter, when I pull a bed, I plant winter wheat, peas, and oats.” To save money she makes her own seed mixes, usually combining nitrogen-fixing legumes with productive grasses. Of the benefits of cover cropping,
Shipman remarks, “It makes your garden look so beautiful. It keeps the weeds down. It defines the garden space, and there is something really satisfying about having that growth there all the time.”
Take heed, however, of potential pitfalls. Cover crops can be hosts for pests and pathogens and should be accounted for in rotations. Planting wheat as a cash crop following its use as a winter cover resulted in hessian fly pressure in Stallings’ fields. For Shipman, terminating at the proper growth stage poses a challenge because “sometimes you need the bed earlier or later.” Grasses can go to seed and become weeds. In a busy season, managing cover crops can fall to the bottom of a farmer’s to-do list. Shipman prefers to mow her covers, and then smother with a silage tarp, a termination process that takes weeks in cool weather. She relies on a combination of flexibility and ingenuity, sometimes with help from feathered friends. “I had an area that I let go too long and (the cover crop) went to seed. So I put the chickens on it, and they ate the grain.” Everybody benefitted.
Picture living roots in the farm field all season, feeding your soil ecosystem and protecting the ground. Cost-share for starting and managing cover crops through NRCS could be available; contact your local agent to learn about eligibility. Or just give cover cropping a try. Stallings advises, “Talk with a farmer that is already growing cover crops, go to a field day. There are lots of opportunities to learn.”
Mary Saunders Bulan served as RAFI’s Farmer Services Director. She and her partner run a small herb, flower, and vegetable farm in Western NC. Prior to joining RAFI, Mary was a college professor teaching agriculture courses, mentoring research, and managing campus farming programs.