By Darren Hefty

If soybeans haven’t been a primary crop for you in recent years, but this year’s market prices have earned soybeans some acres on your farm, here’s what you need to know to be successful.

  1. Fertilize
  2. Double Inoculate
  3. Use a Good Seed Treatment
  4. Use a Pre-Emerge Herbicide Program
  5. Watch Out for Insects
  6. Consider a Fungicide


Next to proper field drainage, the biggest yield-limiting factor holding back soybean yields across the country may be insufficient fertilizer application.  Here’s how you can tell.  Download the free Ag PhD Fertilizer Removal App for your smartphone or iPad.  Choose soybeans as your crop, and type in your yield goal.  Now ask yourself, “Will I fertilize at least to the degree my soybean crop will remove nutrients from my soil?”  For example, we shoot for 70 bushels of soybeans per acre.  The grain alone will remove more than 50 pounds of phosphate and 80 pounds of K2O potassium per acre.  That means you’d need to apply more than 100 pounds of MAP or DAP to keep up with the phosphate removal and about 130 pounds of potash to keep up with the potassium.  Keep that in mind.  You can’t raise good yields and maintain nutrient levels in your soils without adding the proper amount of nutrients, including sulfur and micronutrients.

Double Inoculate

We always recommend using an inoculant when planting soybeans.  Soybean inoculant is just rhizobia bacteria that will colonize on the roots of soybean plants to take atmospheric nitrogen and convert it into a form the plant can utilize.  It’s estimated that the colonies of bacteria in the nodules on soybean roots can produce up to about 70% of the nitrogen needs of a soybean plant.  We recommend double inoculating the seed for anyone raising soybeans in ground where they haven’t been raised often within the last few years.  That likely means treating the soybeans with liquid inoculant AND using a dry inoculant as you load the drill or planter.  Also, you may consider adding some nitrogen fertilizer to deliver 50 pounds per acre of actual nitrogen.

Use a Good Seed Treatment

We recommend using a fungicidal seed treatment and likely an insecticide, as well.  You can find combination products like Inovate, Acceleron and Rancona for about $10 per unit.  We’ve seen returns of 2 to 5 bushels per acre regularly across the region.  We also recommend using a biological product like QuickRoots to enhance root growth and nutrient uptake.

Pre-Emerge Herbicides

Pre-emerge herbicides are critical in soybeans as many Roundup-resistant weeds cannot be effectively controlled post-emerge.  Our preferred program is to use three different sites of action to control nearly all the grasses and small-seeded broadleaves before they ever come up.  In no-till, combine Prowl or Zidua with Authority MTZ (or Valor plus metribuzin).  In conventional-till, use Sonalan or Treflan with Authority MTZ.


Finally, be prepared to scout your soybeans each week throughout the growing season.  You must spray insects at the low end of established thresholds to minimize the damage they cause.  If you are concerned about foliar diseases in soybeans you need to spray before the disease is present to be fully effective.