Interest in Intercropping Increasing

Brenda Frick, Ph.D.

Organic producers are finding benefits to intercropping - seeding two or more crops together in a field. A number of field days across the prairies this summer indicated that interest is growing in this type of diversification.

Intercrops can be used as plowdown crops, with different crops feeding the soil in different ways - legumes for nitrogen and cereals for organic matter, for instance. They can also be used as green feed - pea and oat mix provide a nutritious mix. Intercrops can also be used as seed crops if they are well matched. To be harvested together, the crops need to be similar in their days to maturity, their ease of threshing, and in the combine sieve sizes and rotor speeds they require.

Paul Gaucher, an organic producer near Coderre, Saskatchewan led an interested group through his intercrop fields this summer. Paul finds that intercrops allow him more flexibility. With more than one crop at a time, he can "let Mother Nature decide which plants will do best under the conditions of the crop year".

A field pea and oat mixture works well on Paul's land in the brown soil zone. Field pea does better in some years; oat does better in other years. Together each gets some advantage. The oat grows faster than the pea and reduces weed competition. The oat keeps the pea up, and provides stubble to catch the mixed crop when it is swathed. Neither crop is preferred by grasshoppers.

Steve Snider of New Norway, Alberta is an organic producer who was named "Outstanding Young Farmer" in Alberta. He also intercrops. He finds it expands his options, responds better to variable conditions, and decreases problems with disease, insects and lodging. Steve mixes field pea with oat or barley. The cereal holds the pea up, and acts as a buffer during combining, keeping the pea seed from cracking. The mixture is less weedy than pea alone, and cereals in mixture are less prone to disease.
Elmer Laird from the Back to the Farm Research Foundation (BFRF), a certified organic research foundation near Davidson, demonstrated several intercrops this year. Elmer advocates intercrops for improved weed control, insect control and soil improvement.

Yellow mustard and AC Metcalfe barley was a very successful mixture this year. Both crops grew vigorously. There were very few weeds or insects. Elmer explained that the barley discourages flea beetles and Bertha armyworms.

BFRF also demonstrated flax intercropped with a variety of other crops, including pea, lentil, bean, wheat, barley, and oat. All were seeded on alfalfa stubble. In general, legumes in flax intercrops did poorly this year.

Cereal-flax intercrops were more interesting. The field with the intercrops had a good catch of lamb's-quarters. Elmer claims that seeding a cereal with the flax helps to "use up the surplus nitrogen that would otherwise grow weeds." All cereal-flax intercrops were less weedy than flax alone. Flax did poorly in the oat-flax mixture, though lamb's-quarters numbers were down. Barley and flax worked well together, with both crops doing well, and weed numbers reduced. Elmer will reserve judgment on which intercrops worked best until combining is complete.

Organic farmers are experimenting with options that allow them to mimic nature while reducing the negative impact of their weeds. Intercropping may be an option that does just that.

Native prairie is a dynamic mixture of many species. Differences among species, interacting with small-scale differences in the local environment, produce the shifting equilibrium that characterizes these grasslands. In contrast, much of our prairie agriculture strives for single species domination over hundreds of acres. Perhaps we can benefit from incorporating some of nature's diversity into our cropping systems.

Brenda Frick, Ph.D., P.Ag., is the Prairie Coordinator for the Organic Agriculture Centre of Canada at the College of Agriculture, University of Saskatchewan. She welcomes your comments at 306-966-4975 or via email brenda.frick@usask.ca .

This article first appeared in The Western Producer, and is published here on the OACC website with permission.