Over the past 30 years, Prairie farming practices have evolved to improve overall sustainability and efficiency. One of the most important things farmers have done is to expand and diversify their crop rotations. Not only do longer crop rotations help reduce the risk of disease and pest pressure in crops, but they also provide the opportunity for farmers to rotate the herbicides they apply to their fields to control weeds, as different crops have different herbicides best suited to their production. Results from our 2020 Crop Rotation Survey of Prairie farmers indicate that 30 years ago, between the crop production years of 1991-1994, only 30% of Prairie farmers were including a pulse crop in their rotations. By 2016-2019, 58% of farmers were including a pulse crop. Similarly, the number of Prairie farmers that planted three or more types of crops over the four-year period studied increased from 59% to 80% between 1991-1994 and 2016-2019.
In addition to diversifying their crop rotations, Prairie farmers have also made changes to the way they apply their herbicides to include more tank mixes and greater diversity in herbicide active ingredients. Chemical data from the Crop Rotation Survey was only available from Saskatchewan farmers. Between the crop production periods of 1991-1994 and 2016-2019, the average number of Saskatchewan farmers applying multiple active ingredients per herbicide application increased by 37% for pre-seed applications, 8% for in-crop applications, and 22% for post-harvest applications.
When Canadian Prairie farm management practices are compared to those of the most prominent agricultural regions of the United States (US), multiple differences can be noted. The most commonly practiced crop rotation in the major agricultural areas of the US is a 2-year rotation of corn-soybean. The average number of crop types planted within a rotation is 2.1, with about 60% of cropland planted to one or two crops. Typically, the simplest crop rotations are practiced in the most productive agricultural regions of the US. Perhaps unsurprisingly, the issue of HR weeds, especially glyphosate-resistant weeds, has posed a much greater challenge in the US than on the Canadian Prairies to date.
