Research in Saskatchewan has shown that flax sometimes does poorly after canola or mustard.
This is due to toxic compounds in mature canola and mustard plants and their seedling residues. However, research in Manitoba has shown that flax yields on canola stubble were generally not affected, although small reductions occurred in some years. The problem is most evident where straw and trash from the previous canola crop have not been adequately spread on the soil surface. Canola straw should be spread uniformly, and spring volunteer seedlings should be controlled at an early stage in order to minimize possible toxic effects. Seeding into untilled canola stubble can also minimize the problem.
The poorer performance of flax on canola stubble can also be attributed to mycorrhizae fungi, which do not associate as strongly with canola roots as with flax roots. When flax is grown on canola stubble, the mycorrhizae populations tend to be lower. Mycorrhizae fungi, in their relationships to roots, will increase and improve nutrient uptake, especially phosphorus, a relatively immobile nutrient in the soil.
Flax does well after cereals, corn, and pulse crops, but Rhizoctonia disease may be a problem. Flax does not do well after potatoes as the soil may be too loose and Rhizoctonia disease could also be a problem.
Flax does very well on alfalfa breaking as was observed by alfalfa producers in north-east Saskatchewan.
Crop rotation of at least three years between flax crops is recommended for controlling various soil-borne or stubble-borne diseases of flax.
Flax fits into a rotation easily in soil zones across the Prairies, providing producers with an alternative to cereals and canola.
