Cover crops are a common strategy that farmers use to keep their soil healthy. This practice has many benefits, including maintaining soil nutrients, preventing erosion, and mitigating climate change. These crops are planted in between cash crops, usually during the winter months.
In Canada, it is important to choose a plant that can survive in harsher environments to protect the soil throughout the winter. Common cover crops in Alberta are oats, clover, peas, radish, hairy vetch, fall rye, phacelia, sweet clover, sunflower, and sorghum.(1) Plants like winter rye are perfect for the northern hemisphere, as this plant can still grow in temperatures as low as -30ºC.
While the main purpose of cover crops is to protect and maintain the soil, it also helps mitigate climate change through carbon sequestration. This is the process of capturing carbon dioxide (CO2) from the air and returning it to the soil, as a way to offset greenhouse gas emissions. Plants are a natural form of carbon sequestration through the process of photosynthesis. Carbon that the plant takes in gets stored in its roots and eventually breaks down when the plant dies and becomes a part of the soil’s organic matter.
A 2020 study was conducted on the relationship between cover crops and carbon sequestration, discovering that soil with a cover crop held 13.8 times more carbon,(2) helping to take it out of the atmosphere. Along with their ability to keep top soil in place and return nutrients to the land, cover crops seem to hold nothing but benefits for both farmers and fighting climate change. As a result, cover crop use is on the rise in Canada.
A 2019 survey asked Canadian prairie farmers if they grew cover crops and an astounding 76 per cent of participants reported they grew a full season cover crop. The survey also showed this best practice is only growing. When asked how long they have been using cover crops, the majority (62 per cent) stated they were within the 1–5 year category, while 31 per cent were in the 5+ year category.(3)
This best practice is just one example of how farmers are working to sustainably feed Canadians, protecting the health of their soil and mitigating climate change. As farmers continue to adopt this practice, it will only become easier for others to make the transition, benefitting from the knowledge of their farming community.
Sources
1 Top Crop—Cover Crop Considerations, 2020
2 Scientific Reports: Nature Research—Cumulative Impact of Cover Crops on Soil Carbon Sequestration and Profitability in a Temperate Humid Climate, 2020
3 CAPI—Cover Cropping on the Prairies, 2021