Manitoba producer Nick Boundy offered the following tips about separating intercrops at an intercropping workshop in Brandon, Manitoba. Boundy grows 1,000 acres of organic and 3,600 acres of conventional grain, including intercrops, at his farm near Boissevain, where he also operates a custom seed cleaning business.
1 It’s not seed cleaning.
You are not just removing dockage as you would with cleaning; with an intercrop, you want to separate two valuable, clean crops with some dockage.
2 It’s slower than seed cleaning.
Be prepared that a seed cleaner rated to do 300/bushels/hour may only be able to separate intercrops at a rate of 150/bushels/hour. The advertised capacity is for seed cleaning, not separating two crops. A lot of cleaners are set up to remove around 20% dockage, and if an intercrop is 60% one crop and 40% the other crop, there is 20% more grain being pushed through one spout than it is designed for, so it will have to run slower.
3 It’s harder to get a clean separation of the two crops the closer they are in size.
Peas and canola are easier to clean for example than peas and barley that are closer in size. For separating crops that are very close in size it may be necessary to use an air screen separator, which can be more expensive.
4 Separating costs depend on what kind of cleaner is used.
Typically, separating by size using something like a rotary screen cleaner costs 40 to 60 cents (Cdn) a bushel, but colour sorting can cost 80 cents to $1 (Cdn) per bushel. Using a colour sorter may not be successful if grain is stained for any reason.
5 Do a test run before you seed.
Mix the crops together you plan to seed and try sorting them to see how they work. If you use a hand screen, they should separate easily and quickly, with a couple of shakes.
6 Consider end uses.
Some markets have zero or low tolerances for foreign matter in grain, especially food grade grains that serve niche markets like gluten free. Know what market you are targeting with each crop and their grading requirements.
7 Slow down during harvest.
Harvest at slower speeds, especially during dry conditions, to avoid shattering crops like peas and ending up with split peas in grains that could be an issue for certain end use customers.
8 Consider a compromise.
Consider investing in a less expensive, rotary screen cleaner for a smaller number of intercrop acres, or for crops that are easy to separate and get a custom cleaner to separate trickier intercrop combinations.
9 When will you separate?
Will you separate in the field or store the intercrop to separate later? Do you have the trucks, storage bins and handling capacity available to separate and store the two crops?
10 Think about storage.
Take a harvest sample of both crops to check moisture levels, which could be very different, and make sure both crops are dry going into the bin. Intercrops of different seed sizes could affect airflow in the bin. There isn’t currently a lot of information available about storing intercrops together, although ongoing research is aimed at developing some guidelines for producers.