Cover crops are plants that are grown to cover the soil rather than for the purpose of being harvested. They are used in agriculture to manage soil erosion, soil fertility, soil quality, water, weeds, pests, diseases, biodiversity, and wildlife. Cover crops are nurse crops in that they increase the survival of the main crop being harvested, and are often grown over the winter. They can be used to slow erosion, improve soil health, enhance water availability, smother weeds, help control pests and diseases, increase biodiversity, and bring a host of other benefits to farms and gardens.
Cover crops are traditionally planted on farms but can also be used in gardens. They can be any crop grown to cover the soil and may be incorporated into the soil later for enrichment. Dense cover crop stands physically slow down the velocity of rainfall before it contacts the soil surface, preventing soil splashing and erosive surface runoff. Additionally, vast cover crop root networks help anchor the soil in place and increase soil porosity, producing suitable habitat networks for soil macrofauna. Cover crops can be used to control erosion, suppress weeds, reduce soil compaction, increase moisture and nutrient content of soil, improve yield potential, attract pollinators, and provide habitat for beneficial insects and wildlife as well as food to animals.
Cover crops are different from cash crops, which are those that a farmer sells for profit, such as corn or soybeans. Cover crops’ primary job is to improve the soil. Every time a farmer grows a cash crop, the plants draw nutrients out of the soil. After the harvest, those nutrients need to be returned so that the next crop is equally bountiful. Certain cover crops have the unique ability to “fix” nutrients like nitrogen from the atmosphere and return them to the soil, making them an indispensable tool in maintaining and increasing soil fertility without chemical use.
Effective crop rotations incorporate cover crops to maximize soil productivity without chemical inputs. Cover crops also help the soil bind together, preventing erosion and runoff, while building more pathways for nutrients. They encourage the soil to hold more water, so plants fare better during droughts and are more resistant to pests and disease. Cover crops are also an important tool in weed and pest management. Certain covers are great at outcompeting and smothering weeds or impacting the soil microclimate so that it is more difficult for weeds to survive. Others may release biofumigants – chemicals in the plant tissue that kill or suppress ne...
