The significant impact of agriculture on the economy, environment, and society underpins the importance of sustainable practices in the sector. There are many different approaches to improve sustainability in agriculture, but some common practices are used by producers that aim to increase profit and quality of life while using ecological principles on the farm (Sustainable Agriculture Research and Education, 2022). Farm management practices that benefit the environment cannot neglect the financial aspect with direct connection to better livelihoods. One of these practices that checks many boxes under environmental sustainability with the potential to improve crop yields and finances in the long term is the use of cover crops.
What are cover crops?
Cover crops are crops grown mainly for purposes other than selling the crop. Often, they are used to protect the soil from erosion but there are other reasons why a farmer may choose to use them (see Table 1). A period of time in which there is bare soil is an opportunity to plant cover crops. Some factors should be considered when deciding what type of cover crop to grow, including (1) the season in which the farmer may require the cover crop, (2) the suitability of the crop to the environment and (3) the purpose that the farmer may be seeking for the field. Some functions of cover crops and options to use for each function are shown in Table 1.
How are cover crops useful to the physical environment?
Key benefits of cover crops include slowing soil erosion, adding organic matter, improving soil fertility, enhancing water retention, improving soil structure, storing carbon, and fighting off weeds and pests (OMAFRA, 2021; SARE, 2012). Bare soil can be blown away by the wind or washed away by heavy rain or snowmelt. Lost with the soil is the rich diversity of microbes, organic matter, and nutrients that could pollute nearby water channels, wetlands and lakes. Importantly, for farm production, there is difficulty in growing plants in the remaining soil devoid of life, structure, and nutrients. Dangers of poorly managed soil are recorded in our history. Deforestation for agriculture in Ontario in the late 1800s caused substantial loss of topsoil that created abandoned wastelands where nothing could grow, urging government action in the 1920s and large-scale reforestation. The presence of plants reduces soil erosion, as the above-ground section covers the soil and roots bind and stabilize soil particles.
Cover crops can also regulate water during high flow rates such as spring freshets by uptaking extra moisture, and during water scarcity, by retaining soil moisture. The use of the crops also enhances microbial activity, benefiting soil fertility and plant growth. Certain types of crops can produce adequate above-ground biomass and continue to provide benefits even after dying. Others are useful in developing sophisticated root structures, providing moisture retention, developing soil organic matter content, aerating the soil, and feeding microbes that gather useful nutrients. Depending on the needs of the farm, nitrogen-fixing legumes could be used. Also, most cover crops will benefit the soil and plant health enough to prevent infections and may out-compete weeds, but other crops produce allelopathic effects, which actively produce chemicals to fight weed germination. Photosynthesis and in turn carbon sequestration is another advantage, as the soil would otherwise lack plantation at the time.
How can cover crops help financially?
Planting cover crops should be considered an investment as opposed to a cost, as they eventually pay themselves and often result in higher profitability. Some ways through which cover crops may produce a higher profit include (1) the reduced cost of external fertilizers, herbicides, and pesticides, and (2) the higher crop yields due to healthier soil. Reliance on fertilizers can be reduced because some cover crops can fixate nitrogen from the atmosphere, others can reduce losses by using the nitrogen left behind by the main crop (timing of the release once dead must be taken into consideration), and some have deep root systems that collect nutrients from deeper soil. The cover crop may either be harvested as a secondary crop for profit or be integrated into the soil. Healthier soil with substantial microbial activity can release nutrients from organic matter, also reducing external inputs.
How do you get started?
The benefits of cover crops are promising but to achieve them requires well-constructed planning and management. Getting in touch with regional farmers or farming groups and agencies would help to find suitable crops (i.e., considering growing times and termination options) for the region, season, and purpose, planting dates and seeding rates, crop budgeting, and other considerations, to fully reap the benefits.
There are many variables to take into account when deciding to use cover crops on the farm, but the many wonders of cover crops make the effort worthwhile for the health of the farm, while also serving as a stepping stone to reducing our environmental footprints and making the world a better place.
OMAFRA. (2021). Cover Crops: Adaptation and Use of Cover Crops. http://www.omafra.gov.on.ca/english/crops/facts/cover_crops01/cover.htm#reduce
SARE. (2012). Managing cover crops profitably. Sustainable Agriculture Network.
SARE. (2022). Sustainable Agriculture Research and Education. SARE. https://www.sare.org/