Paige Buck, State Public Affairs Specialist
Cover Crop Mixes? They Just Work Better
Champaign, IL—The old saying, “the more, the better’ may apply perfectly to farmers interested in what soil improvements cover crops can offer. While many find noticeable benefits using single species, those who bump up and plant diverse cover crop mixes seldom go back. According to State Conservationist Ivan Dozier, farmers who use no-till and cover crop mixes tell staff at USDA’s Natural Resources Conservation Service (NRCS) they can breathe new life into their soils. They find increased nutrient cycling and in many cases, reduced use of supplemental fertility inputs.
According to State Agronomist Brett Roberts, there are three key advantages to using mixtures:
No single species can deliver what multiple cover crops deliver in combination. Different cover crops perform different jobs—some fix nitrogen, some scavenge leftover nitrogen in the soil, others control certain weeds or attract beneficial insects, and some extend roots, water, and air deeper into the soil profile.
Each plant species has a unique chemical signature that offers different food sources for good bacteria and fungi living in the soil. This variety creates habitat for a wide selection of helpful soil organisms—most which improve soil health.
With a mix, organic matter production hits the fast track. Diverse plant life above ground creates rich habitat below ground with predator and prey in a healthy balance. You cannot measure biomass produced above ground to measure cover crop success. Think of all the living organisms in the soil that cycle nutrients—that’s healthy and productive.
One idea is to include plants that represent four different cover crop functions: warm-season grasses, warm-season broad leaves, cool-season grasses and cool-season broadleaves. Individual selections depend on practical issues, such as seed availability and cost. A good way to start is using an equal rate of grasses and broad leaves, a 50:50 mix.
“Remember, our true goal is to build soils like those formed under prairie conditions of the past,” says Dozier. “With no-till and cover crop mixes, we can try to emulate the ecosystem functions of natural prairies.” Prairies and prairie soils formed under a diverse mix of plants, a minimum amount of disturbance, and living roots that grew throughout most of the calendar year. Fallow ground without vegetation and living roots within it brings soil health to an abrupt and costly halt.
According to Dozier it is the stable and nurturing environment built with lush and diverse cover crops that we hope to create here in Illinois. And cover crops don’t interfere or compete with the production of grain and commodity crops. They work together to build and protect healthy soils and to ensure healthy farm fields of tomorrow.
To learn more about cover crop mix recommendations suitable for your operation, contact your local NRCS office or visit http://www.nrcs.usda.gov/wps/portal/nrcs/main/national/soils/health/