Corn and soybean prices and perceived lower input costs for beans may have you considering following some 2016 soybean acres with soybeans. Five agronomists suggest legitimate concerns to consider before making your final crop selection decisions.
This panel includes: Betsy Bower, an agronomist and Indiana Certified Crop Adviser with Ceres Solutions, Terre Haute; Bryan Denning, technical agronomist for Stewart Seeds in southern Indiana and Kentucky; Steve Gauck, a Beck’s sales agronomist based in Decatur County and a CCA; Danny Greene, owner of Greene Crop Consulting, Franklin, and also a CCA; and Bryan Overstreet, a CCA and Jasper County Extension ag educator.
These are their biggest concerns if you follow soybeans with soybeans.
Bower: You could see a 5% yield loss because you’re giving up the rotational effect you get following corn. Beyond that, white mold and soybean cyst nematode concern me the most. Sudden death syndrome is also a concern, but our seed treatments look to be helping year in and year out. If white mold was a problem the previous year, and if it’s cool and wet at flowering stage, we could easily see it again. There’s a product sold to control white mold called Contains. It must be applied preflowering if cool, wet conditions are forecast when soybeans reach the R1 and R2 stages.
Denning: The major concerns would be disease, SCN and soil fertility. Most research supports a 5% to 20% yield reduction, depending on disease severity. While this doesn’t always happen, it needs to be considered when determining profit or loss for this rotation. SCN populations can gain momentum when not interrupted in the rotation by a nonhost crop. Also, soybeans are a heavy user of potassium. Nutrient needs must be based on current soil test recommendations.
Gauck: The major concerns to me are soil fertility, diseases and weed control. An application of both phosphorus and potassium will be needed if your soil test results are below critical levels. Be sure pH is in the proper range. Low pH ties up nutrients. Disease pressures will increase, so be sure to change varieties, and possibly maturities, from 2016. And in the age of glyphosate-resistant weeds, you’ll need to use multiple modes of action in your herbicide program. Look at a strong preemergence package that targets problem weeds you’ve had. You may need to look at changing your soybean herbicide trait package.
Greene: The University of Illinois’ Farmdoc recordkeeping program illustrated a 2- to 3-bushel-per-acre decline in yield vs. soybeans following corn in its crop budget. Increased disease pressure from a repeating inoculum source and the lack of breaking cycles is likely the issue. Also, some thought needs to be given to erosion control with less residue cover from soybeans than corn.
Overstreet: I would make sure to plant a soybean variety that has a very good disease package when planting back into a field that was soybeans the year before. If you had nematode issues before, they will be amplified in continuous soybeans.