The onset of autumn brings the final harvests for our food producers. Along with the changing seasons, comes a turnover of farmland as producers prepare for the winter to come. During this time, many farmers across Ontario are using cover crops as a practice to cultivate resilient farm ecosystems. Cover crops support this by reducing erosion, improving soil health, supporting biodiversity, and helping mitigate the effects of climate change. Not only do they offer ecological benefits, ensuring healthy soils for farmland longevity, but they also offer a multitude of economic, and agronomic benefits for farmers. While OFT’s mission is to protect farmland, preserving our farmland’s soils through practices like cover cropping remains just as vital. Whether you’re a large scale farmer or a small urban gardener, cover cropping is an effective way to maintain and enhance long term soil health. Lessons learned from the farm field can be applied to all scales of food production!
What Are Cover Crops?
Cover crops are non-harvested plants grown during off-seasons or between crop cycles. Unlike cash crops, they are left in the field to decay and perform ecological functions like nutrient cycling, weed suppression, and soil improvement [1]. The types of cover crops farmers use vary depending on their goals and needs. Common types of cover crops and their benefits include [2]:
- Legumes (e.g., clover, vetch) – Fix nitrogen in the soil
- Grasses (e.g., rye, oats) – Protect soil from erosion
- Brassicas (e.g., radishes, mustard) – Break up compacted soil
Historically, cover cropping was a common practice until the rise of herbicides and pesticides in the 20th century [3]. Today, its popularity continues to grow as farmers seek to improve the long-term resilience of the land they farm on.
The Benefits of Cover Crops
In 2020, the University of Manitoba released a feedback report [1] which surveyed farmers across Ontario about whether they implement cover crops, and how cover crops have impacted their farm operations and expenses. 91 percent of farmers using cover crops reported significant benefits, and 77 percent of those farmers reported that those benefits accrued within the first three years of implementation. Here are some of the most common cover cropping benefits [3]:
- Soil Health Improvement
Typically, cover crops are left to die in the ground to increase the organic matter in the soil, to promote water infiltration, and boost nutrient availability. Their deep roots break up compacted soils, improving the soil’s structure and the ability for water to move further into the soil layers.
- Erosion Control
By avoiding times of bare soil surfaces, and instead providing year-round ground cover, cover crops prevent soil erosion caused by rain and wind, helping maintain soil structure and prevent the loss of valuable topsoil.
- Nutrient Management
Legume cover crops fix nitrogen, reducing the need for synthetic fertilizers. Other crops scavenge nutrients, keeping them in the soil for future crops.
- Weed Suppression
Cover crops outcompete weeds for light, water, and nutrients. Certain species, like rye, release natural chemicals that inhibit weed growth, reducing the need for herbicides [4].
- Pest and Disease Management
Cover crops can provide habitat for beneficial insects and microorganisms, disrupting pest cycles and reducing the incidence of diseases.
- Increased Crop Yields
A 14-year study in southern Ontario comparing various cover crops highlighted the substantial benefits of cover cropping for crop performance [5]. Over eight years of rotations, researchers saw crop yields rising by 4% to 11% on average. Profit margins improved by 5% to 9%, with tomatoes showing particularly strong results. Even more impressive, fields with higher soil organic matter from cover crops maintained more stable yields year after year, even in the face of drought or excessive moisture.
The Role of Cover Crops in Climate Change Mitigation
Cover crops contribute significantly to climate change mitigation in three key ways [6]:
- Carbon Sequestration
Through photosynthesis, cover crops capture atmospheric carbon and store it in the soil as organic matter, turning fields into carbon sinks. - Reducing Greenhouse Gas Emissions
By fixing nitrogen and improving soil health, cover crops reduce the need for synthetic fertilizers, which are major contributors to nitrous oxide emissions. - Building Climate Resilience
Cover crops improve soil structure and water retention, helping farmland withstand extreme weather events like heavy rains and droughts.
Challenges of Cover Cropping
Transitioning to new farming practices, such as cover cropping, often presents initial challenges, including upfront costs for new infrastructure and seeds, along with the learning curve associated with implementing a new technique.
To support farmers in this transition, several programs in Ontario offer financial assistance and training resources:
- Ontario On-Farm Climate Action Fund (OFCAF): Provides cost-share funding to farmers for adopting beneficial management practices that reduce greenhouse gas emissions and increase carbon sequestration. Eligible practices include nitrogen management, cover cropping, and rotational grazing.
- Sustainable Canadian Agricultural Partnership (Sustainable CAP): A $3.5 billion, five-year agreement between federal, provincial, and territorial governments aimed at strengthening competitiveness, innovation, and resilience in the agriculture sector. This includes $1 billion in federal programs and $2.5 billion in cost-shared programs designed and delivered by the provinces and territories.
- FaRM Resilience Mentorship: A free farmer-to-farmer learning hub by Farmers for Climate Solutions that supports farmers seeking to improve their farmland resiliency through mentorship, online resources and networking.
- Rodale Institute Farmer Training: Offers workshops, webinars, and long-term training internships focused on regenerative organic farming practices.
Conclusion
Cover crops are vital for creating resilient and healthy farmland. They improve soil health, reduce erosion, manage nutrients, suppress weeds, and help farmers build agricultural systems that are more adaptable to climate change. By investing in cover cropping, farmers are securing not only their livelihoods but also stewarding farmland to be used by future generations.
References:
- Ontario. 2022. Cover crops: adaptation and use of cover crops. https://www.ontario.ca/page/cover-crops-adaptation-and-use-cover-crops
- PhycoTerra. 2023. The Benefits of Cover Crops: Everything You Need to Know Before Planting. https://phycoterra.com/blog/benefits-of-cover-crops/#:~:text=Types%20of%20Cover%20Crops%20and,the%20soil%2C%20and%20suppress%20weeds.
- Delta Farmland & Wildlife Trust. 2023. Practical Benefits of Cover Crops. https://deltafarmland.ca/practical-benefits-of-cover-crops/
- Clemson University Cooperative Extension. Farmaha BS, Sekaran U, Marshall MW. 2020. Cover Crops for Weed and Nutrient Management. https://lgpress.clemson.edu/publication/cover-crops-for-weed-and-nutrient-management/
- Cover Crop Strategies. Wichers, G. 2023. Long-Term Ontario Studies Showing Value of Cover Crops. https://www.covercropstrategies.com/articles/2765-long-term-ontario-studies-showing-value-
- Environmental and Energy Study Institute. Bertrand, S Roberts, A, Walker, E. 2022. https://www.eesi.org/articles/view/cover-crops-for-climate-change-adaptation-and-mitigationof-cover-crops
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