About Cover Crops
Farmers are increasingly interested in growing cover crops. As the name suggests, cover crops "cover" ground that would otherwise lie bare. While these crops do not usually become food for us to eat, farmers can use cover crops to boost soil health, improve water quality and sequester carbon.
What is a cover crop?
The term "cover crop" refers to any crop grown between seasons of a primary crop harvested for food, fiber and fuel purposes. Farmland commonly lies bare for months after a crop has been harvested and before the field is replanted. During that intersession, a farmer can plant another crop (commonly a mix of species) for the purpose of improving soil health. This practice is called "cover cropping."
What types of plants can be used as cover crops?
Many plant species (especially legumes and grasses, including small grains) can be used as cover crops. Plants we commonly know as field and pasture crops, including corn, and forages, like rye, can also be used as covers. A cover crop is determined by how it's used (to cover bare ground) rather than its species, though some species will provide advantages over others.
Why plant a cover crop?
When plants (and their roots) grow, generally speaking, the land is better able to retain water and soil is less likely to erode away. Cover crops also feed the microscopic creatures that live in soil. In turn, these microbes help future crops grow healthy and strong.
Cover crops can also:
- Increase crop yields.
- Fix nitrogen (in the case of legumes).
- Sequester carbon.
- Reduce pollution.
- Reduce the need for herbicides.
- Attract pollinators.
- Slow or reduce erosion.
- Increase organic matter in the soil.
- Control plant pests, diseases and weeds.
- Increase biodiversity.
- Conserve water quality.
- Provide seasonal habitat for wildlife.
Cover Crop Research at Noble
Farmers face many questions about which species to choose as cover crops and how to successfully implement the practice on their land. Currently, most species planted as cover crops were bred for other purposes, like forage or grain production, rather than to maximize conservation traits. The best species to plant will also vary from location to location.
Here is what the Noble Research Institute is doing to help get new solutions into the hands of those who use or will be using cover crops:
The Noble Research Institute is pleased to partner with FFAR to promote soil health through the development and adoption of new cover crops across the United States. Twain Butler, Ph.D., research agronomist, serves as project manager for this $6.6 million research initiative made possible by a $2.2 million grant from FFAR. The current focus of this project is to identify species with the greatest potential to improve soil health as cover crops.
Jim Johnson, soils and crops consultant, is evaluating local adaptations of a broad suite of nearly 100 common and exotic species used as cover crops through test plots on Noble farms. Johnson aims to gain information on traits such as above-ground biomass, allelopathy (chemical inhibition of one plant by another plant), soil impacts and economics.
Cover crops are traditionally used in row-crop farming systems, however cattle producers also have opportunities to use cover crops. Many cattlemen in the Southern Great Plains graze their cattle on small grain pasture in the winter. These fields typically lie fallow in the summer. James Rogers, Ph.D., associate professor of forage systems, is evaluating what happens to winter pasture production and economics of the system when a summer cover crop is planted in these pastures. His study is also evaluating the effects of establishing these fields with tillage vs. no-till.
Kelly Craven, Ph.D., associate professor of microbial symbiology, is working with James Rogers, Ph.D., to better understand the impacts of cover cropping and tillage on the microbial communities, and ultimately the health, of Oklahoma soils.