Discover why farmers are returning to their roots

New Kent County farmer Paul Davis has lived by a simple philosophy for many years: Always have something green and growing on every acre, every day of the year. His vibrant fields of crimson clover and hairy vetch offer more than visual beauty each winter, and they are just two of many cover crops that Virginia farmers use in their fields.

What is a cover crop?

A cover crop is a plant that is used to enrich the soil, cash crops and surrounding ecosystem by keeping living roots in the ground yearround. In Virginia, the four main categories are grasses, legumes, brassicas and forbes.

“Before there were affordable commercial fertilizers, cover crops were one of the few sources of nutrients farmers had,” said Davis, who rediscovered the abandoned tradition in 2005 when cover crops were scarce.

“Ultimately, it’s all about ground protection,” said Mark Reiter, director at the Eastern Shore Agricultural Research and Extension Center in Accomack County. “Living plants protect the ground against rain, wind or any adverse impact that can carry it away, while keeping nitrates out of the groundwater.”

With funding from U.S.

Department of Agriculture Natural Resources Conservation Services, Reiter launched an ongoing research project in 2014 to discover the soil health benefits of various cover crop species and mixes. The project was designed to include many rotations commonly utilized in Virginia.

To discover how quickly cover crops can change soil health, Reiter and graduate students established a baseline by growing just corn on “badly beaten-down soil” for nine years. “And then from that basic control and monoculture system, we started adding things to see what matters,” he said. “How do legumes change the crop system? How does cereal rye impact soil health?”

Farmers’ favorite cover crops

Grasses such as cereal rye are popular in Virginia for their ability to scavenge nutrients and grow later in the season. Brassicas like forage radish are useful for relieving soil compaction, scavenging excess nutrients and weed suppression. Legumes like hairy vetch and crimson clover are best for fixing atmospheric nitrogen and providing a nitrogen source for following cash crops.

“But they all have a place when you put them in combination,” said Davis, who found a mix of cereal rye, crimson clover and hairy vetch to produce the best outcome for his operation.

“When you mix cover crops, you get the benefits of all these different functional groups working together, and what mixes you plant really depends on the time of the year and farming conditions,” said Joseph Haymaker, a Ph.D. candidate in Reiter’s research program.

“And something always goes wrong in farming,” Reiter added. “One thing we found was some species outperformed others due to soil moisture, temperature, disease or some other issue.”

Beneficial for anyone

“You get out of it what you put into it,” Davis said. “It takes a little more time management, but the benefits you get from cover crops are much more valuable.”

Davis’ operation has transformed for the better since using cover crops. In just the first year, he could see the soil health benefits of his legume cover crops. Over time, he has increased yields; decreased fertilizer, phosphorous and potassium usage; and saved a significant amount on commercial nitrogen—valued at around $1 a pound.

“Between a home gardener or a big grain farmer, there’s opportunities for everyone in Virginia,” Davis said.

For home gardeners, cover crops can be used when the soil would otherwise be bare, like in the winter. According to Virginia Cooperative Extension, any plant can serve as a cover crop, but often winter grains, daikon radishes or annual clovers are used.

Among the many advantages of using cover crops is that they allow plant roots to supply nutrients to beneficial soil organisms in the ground.

For more information about soil health or cover crops, visit ext.vt.edu or southerncovercrops.org.