As cover-cropping is becoming more and more popular, the idea of a cover crop cocktail has been attracting more and more attention on both farms and gardens. While many cocktails are custom mixes – designed by growers to perform a specific function(s) – the practice refers to any seed mix that contains three or more different plant species which are all planted at the same time.
Gary Richards from Bangor, Sask. plants a mixture of cool and warm season grasses as well as a range of broadleaf species and legumes. His cocktail seed mixes may include as many as a dozen species. A typical mix may include (in pounds/acre): 1.0 radish, 1.0 turnip, 2.0 buckwheat, 2.0 sunflower, 5.0 millet, 25.0 peas, 2.0 annual ryegrass, 25.0 oats, 25.0 winter triticale, 2.0 hairy vetch, 0.5 red clover.
Farmers who plant cover crop cocktails may do so for a number of reasons. Cocktails make excellent forage for livestock, providing a healthy range of minerals and nutrients to the animals and may be available for grazing late in the season when traditional pastures are exhausted.
When added to a regular crop rotation, cocktails can do wonders for rejuvenating soil. They can provide many of the same functions as a regular cover crop but with additional benefits. For example, these crops have been known to:
- Improve soil biology, structure and overall health
- reduce soil erosion
- preserve soil moisture
- outcompete weeds and reduce pests
- reduce reliance on fertilizer inputs
The general advice given to anyone planning a cocktail seed mix is that the greater the diversity in roots and leaves the better the mix.
This is not a new idea, and it’s not overly complex – science tells us that different plant species provide different functions for the soil, so, it makes sense that a variety of species provide a variety of functions in terms of re-establishing soil health.
As Richards told the Western Producer, “Each species has its own little job to do”. Canola is known to have a good tap root, produce plenty of biomass and a canopy to protect soil moisture. Legumes are well known for their ability to fixate nitrogen. Tubers, like radish, have a deep tap root and are great for breaking up hardpan soil and increasing water infiltration. And species like flax and oats, which have a fibrous root system, feed the microbiology and help develop soil structures.
As such, these benefits are most visible when specialty designed cocktails are seeded in specific areas with a specific goal in mind (i.e. increasing water infiltration in lowlands).
While the general goal is often to improve soil health and decrease input cost, Richards claims that even though these crops do wonders in terms of soil rejuvenation and weed suppression they still won’t completely replace the use of chemical fertilizers or herbicides. He notes that synthetics are still a tool in the tool box but the goal is to use less.
Creating the right cocktail to match the soil requirements in a particular region can be a challenge and often comes down to a matter of trial and error. For example, Dan Forgey of central South Dakota, has been planting cover crops since 2006 and notes that in recent years he has decreased the amount of brassicas in his mix as he found they depleted crop residue too quickly, opting instead for more grasses to increase the carbon-to-nitrogen ratio in the soil.
For many farmers considering cover crops, cocktails are seen as a good long-term strategy in terms of sustainability in the broadest sense – for both their business and their soil.
While the process of developing the ideal cocktail mix can have some growing pains, Forgey claims the effort really comes down to an investment in soil health.
Brooker, Robin. (2016). A cover crop cocktail that builds soil. The Western Producer. Retrieved from: https://www.producer.com/2016/01/a-cover-crop-cocktail-that-builds-soil/
Sustainable Agriculture Research & Education (SARE) Program, US Department of Agriculture. (2012). Sustainable Agriculture Research & Education; Managing Cover Crops Profitably, Third Edition. Retrieved from: https://www.sare.org/Learning-Center/Books/Managing-Cover-Crops-Profitably-3rd-Edition
Morrison, Liz. (2011). MixMaster: South Dakota Grower Blends ‘Cover Crop Cocktail’ for Multiple Benefits. Corn & Soybean Digest. Retrieved from: https://www.cornandsoybeandigest.com/conservation/mix-master-south-dakota-grower-blends-cover-crop-cocktails-multiple-benefits