Roadside Guide to Clean Water: Cover Crops

Cover Crops

Cover Crops at a Glance

A cover crop is grown during the off-season (or fallow) after the harvest of a primary production crop, like corn or soybean, and before the next production crop is planted. Typically, cover crops are planted in the fall, after harvest, and they grow over the winter months. Some cover crops are harvested in the spring, but others are simply killed off, or terminated, before the main crop is planted. Some farmers may also be able to plant cover crops during summer fallow. Without cover crops, the soil would be bare at this time and exposed to rain, snow, and wind. Cover crop plants can include legumes like red clover, small grains like winter rye, and other plants like forage radish. Cover crops are typically fast-growing and short-lived plants. Cover crops provide benefits on any barren soil from backyard gardens to large crop fields.

How Cover Crops Work

Cover crops reduce soil erosion by keeping the soil surface covered. The leaves of the plants protect the soil from rain drops that otherwise would splash and blast tiny soil  particles from the land. The roots of the cover crops also assist in holding the soil in place, preventing sediment pollution in nearby streams and other water bodies. Cover crops also help reduce nutrient pollution by using any fertilizer and manure left over from the last production crop season. They can even bring nutrients found deeper in the soil back to the soil surface. After the cover crop is terminated, the nutrients and carbon that are stored in the cover crop will be available to help the next production crop grow. Cover crops also improve soil health and add organic matter to the soil. This helps improve water infiltration and storage in the soil, reducing the volume of stormwater running off the field.

Community Benefits of Cover Crops

• Stormwater: Reduces stormwater runoff
• Climate Change: Promotes climate change resiliency
• Pollution: Reduces pollution
• Habitat: Provides wildlife habitat
• Savings: Provides cost savings

You can expect to find cover crops in suburban or urban settings.

How to Recognize Cover Crops

Cover crops planted after plowing a field will quickly establish to reduce soil loss during the fallow period. Photo by Nicole Santangelo

Cover crops are often used at the same time as reduced-till or no-till practices where soil isn't plowed between crop plantings. Photo by Nicole Santangelo

The taproots of radishes make them a helpful cover crop because they also break up compacted soil before decomposing at the end of winter. Photo by Nicole Santangelo

The remnants of a terminated cover crop act as mulch, as seen here under an actively growing tobacco crop. Photo by Nicole Santangelo

Ryegrass and cereal rye are both used for cover crops. Cereal rye, unlike lawn-grass-type ryes, can grow up to 3–6 feet tall. Photo by Nicole Santangelo. Learn more by watching the video: "No-till Farmer to Farmer-Introduction to the Series."

Cover crops are killed using herbicides or other techniques so that crops can be planted without plowing, reducing soil erosion and sediment pollution. Photo by Lance Cheung, USDA Natural Resources Conservation Service

Cover crops aren't just for farmers; they provide many benefits to backyard gardeners, too.

Photo by Elizabeth Smith