Companion Crops

Knowledge Nuggets

• Companion crops are also known as cover crops, nurse crops or competition crops and are annual crops interseeded with perennial plantings.


• Companion crops are used to prevent soil erosion, suppress weeds and for the production of a useable crop in the establishment year of the forages.


• Companion cropping is more successful in areas that have adequate growing season precipitation.


• Generally, the best companion crops are small grain crops such as barley and oats seeded at half or less than half the normal seeding rate. Occasionally canola is used when seeding alfalfa or clover because of the open canopy at ground level and for ease of weed control.


• Ideally, seed the companion crop first, and then cross seed the forage, this allows for the proper seeding depth of the different forage and crop species.


• Companion crops are competitive for nutrients and moisture. Companion crops are not recommended on sandy soils or under dryland conditions in the Brown soil zone of western Canada, due to the competition for soil moisture.


• Companion crops can choke out the forage seedlings because of thick growth or from crop lodging. If sunlight does not reach the seedlings, growth is stunted and the stand could fail.


• There are no seeding rates for forage and companion crops that will produce maximum yields for both. Increasing the seeding rate of one tends to increase its production at the expense of the other.


• Year-to-year variation in weather has the greatest effect on the relationship between seeding rates and yields of a companion crop and the establishment success for the under-seeded forages.


• When planning seeding forage mixtures and companion crops remember the need of complementing the species mixture that will enable you to control weeds in that first year.


• If you use a companion crop, harvest it early for either silage or greenfeed. If the companion crop is allowed to reach full maturity it will weaken the under-seeded forage or cause a stand failure.


• Be careful not to harvest the cover crop when it is very hot. Forage seedlings are very susceptible to high temperatures and burn easily.