Cover cropping offers a wide range of benefits for both soil health and cash crops while also helping farmers achieve their environmental sustainability goals and improve business performance. This common farming practice helps prevent soil erosion, retain nutrients that might otherwise leach from the field, build organic matter, regulate moisture, and manage weeds and pests. Studies also show that certain cover crops can produce chemical compounds that suppress pathogens and reduce the risk of crop diseases.
In the Fraser Valley, double cropping on high-value land significantly enhances farm profitability by maximizing growing seasons and enabling farmers to produce multiple high-value crops annually. For many dairies, this approach not only boosts overall yield and income per acre but also enhances financial stability. Integrating cover crops into this system has become essential, as they provide high-quality, high-protein feed for dairy cattle, contributing to better animal health and productivity. Moreover, cover crops help reduce input costs by enhancing soil fertility and structure, creating a closed-loop system that maximizes resource efficiency and strengthens overall farm profitability.
Cover Crop Categories
There are three main categories of cover crops: grasses, legumes, and broadleaf non-legumes. Not all cover crop species are equally suitable and profitable for specific management objectives, and each cover crop species performs differently depending on climate and soil properties.
The B.C. Ministry of Agriculture and Food offers an excellent booklet that compares major cover crop species based on key characteristics such as flood tolerance, weed suppression, nitrogen scavenging, and winter hardiness, all tailored to the conditions in B.C.
Grasses
Among various grasses, Winter wheat, Annual ryegrass, Fall rye, Oats, Triticale, and Barley are popular choices, each offering unique characteristics and advantages:
- Winter wheat is a cold-hardy cover crop with a medium-depth fibrous root system, wheat comes in both winter and spring varieties. Though they belong to the same species, some Winter wheat varieties require overwintering before they can begin stem elongation, flowering, and grain filling. Winter wheat is often more effective at suppressing weeds compared to spring wheat and can also provide high-quality forage.
- Annual ryegrass is a fast-growing, densely tillered, cool-season bunchgrass with an upright growth habit. Italian ryegrass, a subspecies of Annual ryegrass, is often mistaken for an annual because it winterkills in many parts of Canada. However, it is a biennial that can overwinter in southern BC and set seed the following spring. Italian ryegrass is known for its high forage quality and rapid establishment, making it an excellent cover crop choice for grazing or silage.
- Fall rye is a hardy grass with an upright growth habit and a deep fibrous root system. Known for its cold tolerance, it establishes quickly in the fall and begins growing quickly in the spring allowing for rapid soil coverage. It can tolerate low fertility, acidic, and wet soils, making it a great option for marginal land.
- Oats are a quick establishing cereal that will die down after the first few frosts. Prefers acidic and loamy soil. Used most commonly as a cover crop in the Fraser Valley, but can be harvested for feed.
- Winter triticale is a hybrid grass species, combining traits of wheat and rye, with an upright growth habit and a medium to deep fibrous root system. It is valued for its cold tolerance and rapid establishment, making it an excellent cover crop for erosion control and weed suppression.
- Barley is a fast-establishing cereal crop that typically dies off after the first frosts. It thrives in alkaline, light soils and is primarily used as a cover crop in the Fraser Valley, although it can also be harvested for feed.
Legumes
Legumes are a plant family known for their ability to fix atmospheric nitrogen, making it available to plants through symbiotic relationships with root-nodulating bacteria. Common legume cover crops include clover, vetch, peas, and beans, with clover providing the highest nitrogen contribution among cover crops (up to 200 lbs/acre). When legume plants die and decompose, they release nitrogen into the soil, benefiting other growing plants.
Similar to fertilizers, the Nitrogen released from a terminated legume cover crop is most efficiently utilized when immediately followed by the planting of another crop.
Broad Leaf Non-Legumes
- Buckwheat is a fast-growing broadleaf cover crop with a fibrous root system, effective at suppressing weeds through its rapid establishment and dense canopy. In BC, it's used to improve soil structure and phosphorus availability for subsequent crops. Buckwheat's roots access insoluble phosphorus and secrete organic acids that release it into a plant-absorbable form, making it ideal for soils with low phosphorus and enhancing fertility for future crops. Additionally, recent research shows that buckwheat can disrupt the life cycle of wireworms, helping to control their population.
- Forage radish, also referred to as Daikon or Tillage radish, is a deep-rooted cover crop known for its ability to break up compacted soils with its large taproot. This root structure creates channels in the soil, improving water infiltration, aeration, and root penetration for subsequent crops. Forage radish also helps scavenge nutrients, especially nitrogen, and prevents nutrient leaching by storing them in its biomass. It decomposes quickly after winter kill, leaving organic matter and improving soil fertility. A few studies have indicated that forage radish may serve as an ill-suited food source for wireworms, increasing their susceptibility to pathogens like entomopathogenic fungi and potentially reducing their populations in subsequent cash crops.
Mixtures
Both single cover crops and mixtures can effectively manage soil health, reduce erosion, and promote biodiversity, with the choice between them depending on factors like regional climate, soil type, and specific goals such as weed suppression, soil health improvement, or feed potential. While individual species offer distinct benefits, such as clover's ability to increase soil nitrogen or grass's strong erosion control, no single crop meets all operational objectives. Using a mixture of cover crops allows growers to combine the strengths of different species, achieving multiple goals more effectively. As always, do not hesitate to contact us to find out more about options that would work the best for your operation.
Here are some examples that might fit your goals:
- Winter cereals can be mixed with legumes, like for example in the Wheat Peas Vetch Winter Mix. Winter wheat provides excellent soil cover and scavenges residual nitrogen, while the legumes fix nitrogen, improving soil fertility for the following crop and offering good forage.
- The Fall Rye, Radish, and Turnip Mix is a versatile forage blend designed to enhance soil health and provide high-quality feed for livestock. Comprising 79% Fall rye, 19% Aerifi radish, and 2% Purple top turnip, this blend offers excellent winter hardiness, rapid growth, and soil-improving benefits. Fall rye serves as a robust cover crop that protects soil and scavenges nutrients, while Aerifi radish and Turnip radish contribute to soil aeration, nutrient cycling, and increased forage diversity. This combination is ideal for improving soil structure and fertility, while providing nutritious forage for grazing.
- The Dairy Boost Mix is an excellent example of a carefully crafted mixture suited for forage production and soil protection in BC region. % by weight: 70% Winter wheat, 15% Italian ryegrass, 15% Winter triticale). The Dairy Boost mix creates an adaptable, winter hardy and nutritional blend perfect for silage and cover cropping. Excellent dry matter yield, digestibility and amino acid content from the winter triticale paired with the palatability of the ryegrass results in cows reaping greater benefits from their feed regarding milk yield and nutrient.
Written by: Dan Malamura and Josh Matzek