Ontario research has demonstrated that winter wheat in rotation improves corn and soybean yields. But with greater returns on corn and soybean acres, do these yield benefits outweigh revenue reductions from wheat acres? We will answer that question using University of Guelph research to help you make the most profitable crop rotation decisions.
The simple answer
Rotations including winter wheat provided higher net returns compared to rotations with only corn and soybeans, when straw is sold. Grow winter wheat every 3-4 years in rotation.
A little more information
Winter wheat boosts corn and soybean yields. In long-term rotation-tillage system trials, crop yields increased an average of 5.2% and 2.9% for corn, and 12.5% and 7.7% for soybeans at Elora and Ridgetown, respectively (Figure 1).
Wheat also increased net returns, but not immediately. At the Elora trial – established in 1980 – the benefits of winter wheat in rotation took several years to show up. Growing wheat once in four years did not lower net returns in the first 20 years of the experiment. But after 20 years, wheat provided an economic advantage – $14 more in annual net returns per acre (Figure 2). Revenue from straw was not included in the analysis, but if baled and sold would have boosted net returns by a further $20/acre/year for wheat-containing rotations in both eras.
The full story
Economic assumptions
University of Guelph researchers conducted a detailed economic study of the long-term rotation-tillage system trials to draw the conclusions (Figure 2). In the study, cost assumptions were taken from the OMAFRA 2017 Field Crop Budgets publication. Crop prices were set at $4.93/bu for corn, $12.95/bu for soybeans and $5.63/bu for wheat.
Straw revenue plays important role
At the Ridgetown trial location (established in 1995), the corn-soybean rotation had a slight edge over corn-soybean-wheat, with a $21/ac higher net return (Figure 4). However, when straw revenue was considered, the three-crop rotation provided a slightly higher net return. This advantage was enhanced when an under-seeded red clover (RC) cover crop was grown (Figure 4). This economic advantage to wheat-containing rotations will likely grow over time (as seen at Elora).
Bottom line
Including winter wheat in rotation once every three or four years adds value to the entire cropping enterprise. Although the economic advantage of wheat-containing rotations can take time to occur, Ontario farmers are realizing immediate and additional value through practices such as seeding annual forages following wheat harvest, acquiring nitrogen credits with under-seeded red clover and minimizing compaction through summer manure applications.
To view the full research article: Janovicek K, Hooker D, Weersink A, Vyn R, Deen B. Corn and soybean yields and returns are greater in rotations with wheat. Agronomy Journal. 2021;113:1691–1711. visit https://doi.org/10.1002/agj2.20605