FORT WAYNE, Ind. — Cover crops – touted as a way to improve soil health – may also have benefits for humans, a soil health advocate and researcher said.
Better soil health “can help not only with the environment, but with (human) health problems too,” explained Jill Clapperton, co-founder of Rhizoterra, Inc. “We have it in our hands to feed the world, but we can also help keep the world well.”
Many of the plants used for cover have nutrients valuable to humans as they fight disease, inflammation, or the impacts of aging, she said. Zinc, for example, is found in crops such as buckwheat, forage peas, and rye; it’s especially high in mustard.
Foods rich in zinc may help in the mitigation of neurodegenerative disease symptoms found in Alzheimer’s and Parkinson’s diseases, Clapperton noted. In Alameda County, Calif., doctors are recommending food prescriptions in some cases rather than prescription medication.
For patients with pre-diabetes, doctors may suggest they eat leafy greens and whole grains instead of taking medicine. Farmers have partnered with county officials to regularly provide produce to some clinics.
Clapperton, who started Rhizoterra in 2011, spoke to about 160 attendees at the “Seeing Green: Fields and Profits” conference on March 11. The event was sponsored by the USDA’s Natural Resources Conservation Service and the North East Indiana Conservation Partnership.
She said use of no-till and conservation tillage is not enough to guarantee healthy soils. “Plant cover stops soil erosion,” she explained. “We don’t want to lose any soil. We don’t want to lose it in the winter, spring, summer, or fall.
“We are building a system, we’re not trying just one thing. It’s about finding that balance. I want you to experiment. I want you to try things.”
Soil is a habitat for plants and other living creatures, Clapperton said. They all have certain requirements in order to thrive and function normally. The appearance of earthworm middens – a mixture of worm feces and plant residues – is a good indicator of soil health.
“Earthworms prefer a stable habitat with a diverse food supply. They’re ecosystem engineers. They know what they like and know what’s good for them. The closer the carbon-to-nitrogen ratio, the more earthworms prefer it,” she said.
When choosing seeds for crops and cover, farmers should focus on seed quality. “You don’t want your seeds giving away stuff,” she pointed out. “We’re seeing a lack of nutrient density in some seeds, but you need to have enough density in that seed.”
The goal of intercropping – the practice of growing two or more crops in close proximity – is greater yield and/or reduced inputs, Clapperton said. Over the last several years, she’s researched various crop combinations, including Clearfield canola with maple or yellow peas, yellow mustard with red lentils or maple peas, and golden flax with Kabuli chickpeas.
“The total yields of fields grown with two or more species at a time or in alternating years can be higher than the most productive monocultures,” she noted. “Different crown heights can accommodate different light requirements, and different root systems can minimize competition for nutrients. Rotating crops reduces pest populations and ground-hugging plants can suppress weeds.”
Every different seed placed in the ground creates a distinct rhizosphere, the most biologically active area of the soil, Clapperton said. The rhizosphere is made up of plants, plant roots, soil attached to roots, and soil influenced by roots.
“Each plant species or crop species modifies the soil and soil organisms in ways that can benefit, inhibit, or have no effect on the establishment and growth of the subsequent crop,” she said. “We can use these processes to manage crops, weeds, diseases to increase soil and plant health and productivity, and animal and human wellness.”