There’s not always a lot of discussion around planting soybeans in the same field multiple years in a row, but current commodity prices may be putting some pressure on that rotational strategy. What’s the profit potential of so-called “second year soybeans”?
A trio of University of Wisconsin Extension researchers, including Shawn Conley, Seth Naeve and John Gaska, covered this very topic in the latest UW Extension newsletter.
“We do not advocate this practice,” they warn, noting that planting soybeans in consecutive seasons is not a best management practice. Nonetheless, they say there are seven strategies farmers that farmers who choose this rotational practice should adopt.
1. Change varieties and select strong disease resistance traits to match known problems in your field.
“Every variety has a weakness, and planting the same variety on the same land two years in a row will expose that weakness,” the researchers note.
2. SCN proliferates in multi-year soybean rotations, so test for SCN and choose SCN-resistant varieties.
3. Scout fields more intensely to stay ahead of disease problems.
4. Lower seeding rates in fields where white mold has been a problem.
5. Max out the fungicide rates of your seed treatments.
6. “Use a pre-emerge herbicide, and use multiple modes of action,” the researchers recommend. “If you had weed escapes, expect even larger problems in soybean after soybean.”
7. Soil sample, and replace K if needed.
“Growers often routinely rely on carryover fertilizers for soybean when rotated with well-fertilized corn,” the researchers write. “Soybean after soybean may require additional fertilizer, especially K.”
Be wary of lost yields, the researchers add. Their data shows that three or more years of continuous soybean erases 4 bu. of yields per acre.