Travelling through Delta in the fall or early winter you might wonder why there are fields that are still covered in green.
Some fields may be growing forage for animals, but many will be growing cover crops. Cover crops are different than cash crops, in that they are not harvested, instead they are grown for their many agronomic and ecological benefits and tilled in the spring.
It is because of these many benefits that the Delta Farmland and Wildlife Trust has been assisting farmers with the cost of planting cover crops for the past 31 years. In fact, the first stewardship program offered by the Trust was the Winter Cover Crop program, originally called “green fields.”
Cover crops provide an important food source for waterfowl throughout the winter.
The Fraser River estuary is located along the Pacific Flyway, a major north/south route for migratory birds that extends from Alaska to South America. Each year, more than five million birds pass through this area with many stopping to rest and forage.
The estuary supports the largest density of over-wintering birds in Canada and is considered Canada’s top Important Bird Area. Fields that have been cover cropped act as a lure to draw these birds away from parks, playing fields and high value forage fields. Waterfowl grazing in these areas, particularly by Snow Geese and American Wigen, can be extremely damaging as they eat the roots of the grasses as well as the growing tips. Cover crops also lure waterfowl away from areas where they could pose a danger, particularly around airports.
Farmers also plant cover crops for their many agricultural benefits. Having fields covered in vegetation over the winter reduces soil erosion from heavy winter rains, which helps to conserve topsoil.
Cover crops scavenge excess nutrients from the soil before they can be leached away, keeping the nutrients in farm fields and out of waterways. The roots improve soil structure, which helps loosen compacted soil and contributes to better water infiltration. Fungi and bacteria that live in soil will feed on the carbohydrates that plants release through their roots and other soil organisms then feed on the bacteria and fungi which contributes to improving soil health. In spring when the cover crop is tilled in the additional organic material and nutrients helps to reduce the need for additional fertilizers.
Cover crops can consist of one to several species of plants. Many farmers are experimenting with planting multi-species mixes including plants such as grasses, legumes, and brassicas. Different types of plants provide different benefits. For example, spring cereals such as oats will establish quickly but may not survive prolonged freezing, whereas some clovers and ryegrass are winter hardy and may continue growing into the spring. Brassicas such as radish attract pollinators and can suppress detrimental nematodes and soil borne diseases. A cover crop that forms a dense stand can outcompete weeds and can have weed suppression benefits for the following crop. Farmers develop a cover crop strategy based on the growing conditions in their fields and requirements for the crops that will be planted in the next season.
In Delta more than half the fields planted with cover crops will be completely grazed by waterfowl by spring. Supporting wildlife, improving soil health, reducing soil erosion and nutrient leaching, and even increasing the amount of carbon in the soil are some of the ecosystem services that cover crops provide for the community.
-Submitted by Delta Farmland and Wildlife Trust
