The Agronomists, Ep 73: Colin Elgie and Jack Payne on diagnosing nutrient deficiencies

Corn treated with a pre-emerge residual/glyphosate tank mix.

Nutrient deficiencies don’t always follow the textbook examples — sometimes a crop short of nutrients can look okay, but be behind in maturity, patchy, or show signs of poor reproductive performance.

To dig in to common — and less common! — nutrient deficiencies, we go to newly minted soil nutrient specialist with the Ontario Ministry of Agriculture, Food and Rural Affairs, Colin Elgie, and agronomist with South Country Co-op in Alberta, Jack Payne.

This episode of The Agronomists is brought to you by ADAMA Canada, the Mind Your Farm Business podcast, and our July 5th webinar on flea beetle management (more here).


  • Welcome Colin to the show, and to his new role for OMAFRA
  • Jack didn’t know Ray Dowbenko would be in the comments
  • How do the 4Rs play in to the nutrient deficiency discussion? Start with the right rate
  • A drought and high fertilizer prices may have dissuaded some from applying the level of nutrients necessary for full yields
  • When working out field symptoms of a suspected deficiency, Colin reviews every pass that has happened since the last soil test (get your soil tests done!)
  • Physical changes in a field can impact nutrient uptake, such as compaction or crusting or flooding, or smeared sidewalls
  • Visual cues are only clues, but take in to account patterns in the field and where on the plant symptoms show up
  • But you can’t positively identify a nutrient deficiency just from visual symptoms. You need a soil test or a tissue test or a combination of both.
  • How do we feel about tissue tests? Every test has limits, but they are an indicator of nutrient levels
  • There can be issues with sampling, sample storage, or shipping, there’s always margin for error
  • Colin loves tissue tests. They’re not perfect, but can usually confirm your suspicions of a visual diagnosis
  • Clip 1: Boron deficiency in corn 
  • If a crop looks great but tissue test suggest a boron deficiency, do you apply B?
  • Nutrient in the soil doesn’t mean that nutrient is available to the plant
  • Micronutrient tests are useful, but not required to be tested every year
  • Soluble nutrients move with the water in the soil, so things like nitrogen, or boron, are very soluble. So when we’ve had a lot of rains, that’s when you tend to see a lot of those nutrient deficiencies showing up
  • Nine times out of 10, if your soil test levels are decent, you’re not going to see a deficiency unless there’s an additional stress on that plant
  • Maturity differences can be phosphorus-related, not the variety
  • When we see a line we know it’s something mechanical, it’s something equipment related, if the variety is the same
  • To use chelated or non-chelated product? Chelated is necessary for foliar applications
  • Purple corn plants: what happened? Field history tells the tale
  • Mycorrhizal fungi play a huge role in soil phosphorus availability. The interaction between those two organisms to really make it work.
  • Clip 2: Mixing sulphur application with herbicide pass on wheat
  • Why would a double-sulphur app lodge wheat? It’s the added N, possibly
  • Sulphur is very important for canola and alfalfa (big users) but if protein content is lacking in wheat with good N, it could be S is holding back the protein
  • Salt burn can look like something completely different
  • Let’s talk potassium! K is usually not limiting in Western Canada, but don’t assume it won’t ever be
  • Potassium in dry weather and with reduced tillage equals much less availability
  • What’s the next cool soil testing gadget coming?

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