12 GERMINATION.CA SEPTEMBER 2018 you can clean out every canola seed in pea,” he says. “There’s always going to be half a per cent kicking around.” In terms of agronomics, there’s both an art and a science to inter- cropping, and it takes keen observa- tion and a lot of trial and error to figure out what works best. For Rosengren, who this year will grow forage oats/peas, flax/chickpea, corn/soybean/flax, pea/mustard/ lentil, camelina/lentil, and flax/chick- pea/soybean, intercropping works best when the crops have different resource requirements — water, sun- light and topography. “Peas and lentils perform better in hilltops on lighter soils, and soybeans and peas are wetter crops for us, so we change the populations to put them in the areas where they’re best suited. We’ve gained extra yield by doing so,” he explains. Last year, Rosengren saw some- thing extremely interesting in his barley crop, which was planted alone on a full soil profile following an intercropped mixture. Though it was a very dry year with only 2.5 inches of rain, he got the highest yields on barley he’d ever seen. “I think there’s been more disease impact than I’ve appreciated in those particular zones, because even in the wet years when there’s moisture we haven’t seen the yields spike that high,” he says. “Why do we not nor- mally achieve those yields? I believe it’s because of leaf diseases and sub-clinical or sub-treatment levels of diseases and stresses in a monocul- ture situation that’s suppressing the yield. Putting in other crops has been the best way by far to suppress the diseases, way better than fungicides.” Rosengren runs full oil profile tests on his camelina for Three Farmers, and when intercropped, the camelina oil is of very high quality, quite apart from potential damage wrought by diseases and pests. “This is an indication that we’re not fully capturing the potential that’s out there,” he says. When Rosengren and his Three Farmers partners first started inter- cropping, they ran strip trials to com- pare intercropped and monocropped systems, but they soon abandoned For producers considering intercropping for the first time, it’s important to “start small” and get comfortable with the process. the practice because the benefits were so obvious. “There are a million products that offer two extra bushels of yield per acre, but that’s pretty hard to meas- ure,” he says. “When you’re talking 25 to 30 per cent extra yield, it’s significant enough to measure. It was dramatic enough that we quit doing the strips.” Axten also believes intercropping is the way of the future for western Canadian farming. “I think of all the problems that have happened in agriculture, things that have come to light in the last 15 years. We keep trying to do this monocrop thing, but I don’t think we’re showing that it works very well.” An example of pea roots with nodules growing close to canola roots. Courtesy Scott Chalmers