By Dr. Michael Schwartz

Sustainable agriculture is multifaceted and includes, but is not limited to, the water and fertilizers used for our crops, the transportation cost (both financial and environmental), and soil health. Soil health contributes to sustainability by contributing to productive agricultural lands and this is crucial for healthy crops. One way to improve soil health is to plant cover crops. Cover crops are crops planted in between growing seasons to maximize soil health and contribute to a healthy agroecosystem. One main benefit of cover crops is their ability to hold the soil in place and prevent soil erosion during winter. Additionally, cover crops can prevent soil compaction and provide essential nutrients to the soil. As the cover crops grow older, they suppress the growth of unwanted weeds, which can compete for nutrients and host pathogens which can have devastating effects on the crops grown during the spring and summer.

Cover crops are beneficial for a plethora of reasons, and they require a few characteristics in order to be successful. The ideal cover crops are relatively fast growing and produce many leaves with an intricate root system. The leaves suppress weeds by creating shade under the canopy and large roots to keep the soil in place while promoting a healthy microbiome. Since cover crops are planted in the fall and early spring they must be able to withstand the colder temperatures and survive the occasional frost.

In regerneratice agriculture, cover crops are often used as food for grazing livestock that in turn, fertilize the land

Several species of plants make good cover crops. For example, legumes (clovers and vetches) are able to grow quickly and survive cooler temperatures. They provide ample green manure to the fields in which they are grown. Green manure is plant material that is incorporated into the soil to provide extra nutrients at the end of the growing season. A unique characteristic and added benefit of legumes is their ability for their roots to form symbiotic (mutually beneficial) relationships with soil bacteria to fix nitrogen from the air. In return the bacteria are given essential nutrients for their own metabolism. The result of using legumes as a cover crop keeps the soil fertile and requires less fertilizers for growing future crops.

Other impactful cover crops include several grass species, such as winter rye and oats. These plants have fast growing roots which hold the soil in place. However, oats have the ability to become weedy in warmer seasons and should be planted in the fall. These cold-sensitive plants will grow quickly in the fall and die after a winter frost, but the roots will remain bound to the soil preventing erosion.

While most, if not all, of us reading this can easily replace the soil we grow our food in with a few bags of potting soil, we can still have healthy reusable soil every year. Cover crops in the garden provide the same benefits to soil health as they do to a farm. Legumes will fix nitrogen and grasses will prevent soil erosion and smother weeds, even in container gardens. Planting cover crops in the spring can choke out weeds and provide nutrients to warm season garden crops. In contrast, planting late in the summer to early fall can allow for cool season cover crops to replace the lost nutrients after they die in the winter, while preventing the soil from eroding.

Cover crops have a lasting benefit to soil health and are major contributors to sustainable agriculture. They are useful on a large agricultural scale and in small-scale urban gardens with benefits that can be seen well past their lifetime.

Cover Crops: What They Are And How To Use Them

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