Now that many soybean crops are getting to where the crop has fully emerged (usually about three to four weeks after planting) it really is time for those crops to get their spring checkup. It’s the time for growers and agronomist to get their hoops or tape measures and do a plant stand assessment.  The spring checkup is the field visit that will give you the greatest opportunity to protect your profit.

Why is the spring checkup so important?            

  • It’s when you learn the most about what costs the most – Seed can make up half the direct cost of growing soybeans. The spring checkup allows you to see how good of a job of seeding you did. Are you hitting your desired plants per acre target? The spring checkup gives you the chance to do stand counts. And it is an opportunity to inspect seedling health.
  • It’s when you evaluate the major yield driver – If you are counting the plants anyways you have a chance to dig some of them up. Nitrogen is the yield driver because high yielding soybeans need a lot of Nitrogen (N); approximately 6 lbs per acre for every bushel harvested. The spring checkup is your chance to check nodulation.
  • It’s when you are battling the greatest yield threat – Soybeans are not competitive with weeds when small and research has clearly show that early weed control protects the greatest amount of yield. The spring checkup is your chance to assess weed populations and target post emergent applications. And don’t forget to reassess weed control after spraying as well.
  • It’s when you might be deciding to play catch up – If you couldn’t roll your soybeans right after planting, you may be considering post emergent rolling. Rolling at the right crop growth stage is important for minimizing plant damage. Ideally, you are aiming to roll at the first trifoliate. The spring checkup lets you get a handle on crop growth stage.
  • It’s when you might see a disturbing change – A few weeks after planting is when we might start to see yellowing in soybeans. A generalized yellowing of soybean plants may mean that they have exhausted their cotyledon based N supply and are now starting to nodulate and fix N. Soybeans need to starve for N a bit to get the message to start N fixation. The spring checkup lets you ensure that nodulation is proceeding or interveinal leaf yellowing may mean that your soybeans are starting to experience Iron Deficiency Chlorosis (IDC). The severity of IDC varies from year to year and is depending on weather, soil properties and variety genetics. The spring checkup is your start on monitoring this condition in your fields and determining severity.

For a comprehensive but easy to watch explanation of the ways a spring checkup of soybean crops will protect your profit, check out our latest Manitoba Agriculture YouTube feature at: Soybeans – Time for the Spring Checkup.

Submitted by Dennis Lange (IDS – Pulses, Altona) and Terry Buss (FPES – Pulses, Beausejour), Manitoba Agriculture

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