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Are There Merits To Intercropping?

Increasing yields by planting two crops in one field has consistently worked for one southeast Saskatchewan farmer. However, the results were not replicated in a field trial conducted by the Indian Head Agricultural Research Foundation (IHARF) in 2010.

Research manager Chris Holzapfel said he believes there are merits to intercropping, but the study IHARF conducted planting alternating rows of peas and canola in one field did not show any yield benefits.

“At Indian Head, we didn’t see any advantage to intercropping compared to growing the two crops on their own. The canola yielded slightly under and the peas yielded slightly over, but it’s too early to understand why.”

Midale farmer Colin Rosengren suggested the study to IHARF based on the positive results he has observed over the last seven years with intercropping on his 5,000-acre operation. Rosengren has had tremendous success with planting a variety of crops together from peas and canola to a flax/chickpea mix and even mixes of peas/canola/lentils and peas/canola/barley.

His first foray into planting peas and canola together in 2004 resulted in an increased profit of $40 per acre over and above what each crop netted on his mono-crop check strips.

Low grain prices in 2004 prompted Rosengren to try the intercropping experiment on 120 acres which involved seeding a two-third rate of canola down one point of his air seeder and putting a two-third rate of peas down the fertilizer point.

“The low prices and tight margins in 2004-05 made us look at different things like organic, pesticide free and intercropping as well. Martin Entz, of the University of Manitoba had positive results, so out of interest I thought I’d try it to try and find more net profit.”

While Rosengren applied fertilizer on his first pea/canola intercropping field, he was able to reduce the amount, as well as reducing his herbicide costs. Seeding and harvesting the canola and peas together was possible using existing equipment, but a cleaner did have to be purchased to separate the two crops.

“We were pretty excited that first year because it showed pretty good potential and it gave us a way of growing peas and making money because back then the price of peas was less than $4 per bushel.”

In terms of the Indian Head results, Rosengren said the 12-inch spacing between the alternating rows of canola and peas led to the peas clinging to the canola, hampering its growth. Rosengren has had more success with mixed rows, versus the alternating rows used in the IHARF study.

In 2005, the Midale farmer expanded his intercropping acreage, planting a variety of combinations that included mustard and peas, along with canola and peas. Each year, the number of intercropped acres increased with Rosengren now planting half of his 5,000 acres with two crops in one field.

“Flax and chickpeas has been the most economically successful as we were able to get a full crop of flax plus 14 bushels per acre of chickpeas and that was without using fungicide,” said Rosengren, explaining that chickpeas typically require a minimum of four applications of fungicide per growing season.

Rosengren has also experimented with cereal crops, however, that has been less successful.

“The cereals are bred to be so competitive on their own, that there’s just not much of a gain to be made.”

Maryfield, Sask. farmer Darcy Boon tried intercropping mustard and peas last year after reading about the positive test results on peas and canola produced by the Westman Agricultural Diversification Organization (WADO) which serves the southwest region of Manitoba.

Following studies on intercropping canola and peas in 2009 and 2010, WADO researcher Scott Chalmers found that the risk of canola shattering was reduced as the peas appeared to act as an anchor for the canola. In addition, the risk of Mycosphaerella blight was reduced in the peas, possibly due to lower pea plant density or upright pea growth allowing for greater plant ventilation and reduced pea-to-pea plant contact.

After sowing the peas first and broadcasting mustard and harrowing it in, Boon was disappointed with his crop. He chose mustard because he is an organic farmer and there isn’t organic canola seed. He was also hopeful that the nitrogen-producing peas would supplement the nitrogen needs of the mustard. However, his peas yielded only seven bushels per acre, with the mustard not faring much better. Boon believes his experiment failed due to ill-timed rains which forced the planting and harrowing of the mustard seed after the peas were already up.

“I did a bad job of seeding it. In the future, I would let the experimental farms do it and I’d like to see it done in a field-scale demonstration, or even a few acres, as opposed to smaller plots.”

Rosengren said he’ll continue intercropping 2,500 acres as his year-over-year profits have risen by an average of 25 per cent in the mixed-crop fields. Some of his highest positive profit margins have been on a canola/pea mix which has overyielded by as much as 40 to 50 per cent compared to planting a single crop.

“It’s definitely a worthwhile practice as it nets significantly more profit consistently.”

He recommends that other farmers try it, particularly if the moisture content of their land is high.

“A drum cleaner (to separate the harvested crop) is really all you’d need over and above what you already have,” said Rosengren, adding that the combination he’d start with is a pea/ canola mix. “If you’re planting peas, consider throwing in canola with it, just have a cleaner ready to clean it as you harvest, then take it right to town and put the extra money in your pocket.”

Holzapfel said IHARF will continue investigating the merits of intercropping, expanding its research to include more variables and different soil types.

ChristaleeFroesewritesfromMontmartre, Saskatchewan.

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Christalee Froese writes from Montmartre, Sask.

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