Cover Crops a Good Tool for Soil Health
Agriculture and Agri-Food Canada
Cover crops can help resolve a host of soil health and environmental concerns, especially nutrient retention, according to research conducted at Agriculture and Agri-Food Canada's (AAFC) Harrow Research and Development Centre in Ontario.
"Cover crops are an amazing tool that producers have available to them," says Dr. Craig Drury, soil management and biochemistry researcher at Harrow. "The cover crop increases soil organic carbon, improves soil structure and overall soil quality, and can also improve the drainage of soil."
Cover crops are planted in the late summer or early fall following the harvest of a cereal crop, or inter-seeded into an annual row crop, such as corn. They can capture the residual nitrogen that remains in the soil at the end of the growing season and effectively tie it up over winter. The nitrogen is then released into the soil when the cover crop decomposes in the following spring. This is important because, as Drury says, farmers "want to hold a nutrient like nitrogen in the soil as long as they can and make more of it available for future crops".
A five-year field study determined that cover crops improved soil health not only by absorbing nutrients from the soil but also by reducing the amounts of fertilizer nutrients leaching through the soil and out of the root zone. "The cover crops act very much like a sponge," says Drury, adding they are "very beneficial from a water quality standpoint" because they help reduce surface runoff while absorbing nutrients from the soil.
Water loss, through runoff or leaching, varies according to the whims of the weather, but "this is where cover crops fit into the picture really well," he says. As a result, this practice can help farmers minimize runoff during periods of excess moisture – or drought.
"There's an appetite for soil management practices that promote soil health."- Dr. Craig Drury, Soil Management & Biochemistry, Agriculture and Agri-Food Canada
Planting cover crops is cost-effective and the benefits increase when used with other soil management practices, such as tile drainage and sub-irrigation. Ultimately, producers are more likely to enjoy higher crop yields, increased long-term savings and reduced environmental impact.
The Harrow Research and Development Centre in Ontario is among a network of 20 AAFC research centres across the country. The Centre's mission is to develop and transfer new technologies for the production and protection of greenhouse vegetables and ornamentals, and field crops, including soybeans, edible beans, corn, winter wheat and tomatoes.
Key discoveries (benefits)
- Producers want to manage the health of their soils using sustainable practices.
- Cover crops are effective in absorbing nutrients after harvest, thereby improving water quality.
- Cover cropping can recycle nutrients and enhance crop yields in subsequent growing seasons.
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