By Sherri Roberts PAg., Crops Extension Specialist, Weyburn
Have you ever considered the impact rotation decisions have on your crops? Does it make a difference if you plant peas after canola or canola after peas? Crop rotations can have an effect on yield and fertility as well as insect and disease issues.
Crop rotation is effective in reducing the number of European corn borer. Their life cycle involves mature larvae overwintering in corn stalks and debris. New Bacillus thuringiensis containing genes have assisted in corn borer control but crop rotation needs to be practiced to prevent the gene breakdown, which was observed by Smith and Schaafsma in Nova Scotia in 2018.
Work done at the University of Minnesota has shown late-summer seeded oats can reduce disease severity from Aphanomyces euteiches, a major root rot disease impacting peas and lentils in the Western Prairies. While additional research on this topic needs to be done, it is a clear indicator that different plants can inhibit disease issues.
Work done at the University of Saskatchewan and at Agriculture and Agri-Food Canada has shown fields contaminated with Aphanomyces euteiches require an eight-year rotation in order for inoculum spore load levels to be brought down.
Having peas too close together in a rotation increases diseases like mycosphaerella blight, powdery mildew, bacterial blight and Ascochyta pisi. To combat these, four year rotations should be used. Gan and associates researched the impact pulses in rotations could have on building up residual nitrogen in the soil. The rotation of pea-mustard-lentil-wheat had the greatest impact on building nitrogen reserves into the soil.
If you’re wondering how you can expand your rotations, there are a lot of resources available to assist you. The Saskatchewan Crop Insurance Corporation offers data on how different varieties perform in your cropping zone.
For assistance evaluating your crop rotation, contact your regional crop extension specialist or call the Agricultural Knowledge Centre at 1-866-457-2377.