The Agronomists, Ep 49: Don Flaten and Dale Cowan on soil amendments


There are plenty of things farmers can add to soil other than a commercial fertilizer to add carbon and feed microbes. Increasingly, there are products that promise increased nutrient availability or even nitrogen-fixation for non-legumes.

Whether or not the products work as they should and determining the best situation to use them is yet to be determined, as Dale Cowan, senior agronomist with AGRIS-Co-op, explains in this episode. Plus, there’s the oldest of the soil amendments — manure. Don Flaten, professor emeritus from the University of Manitoba, walks us through interesting long-term research results from using manure as a “nutrient bundle.”

In this episode of The Agronomists, brought to you by ADAMA Canada, hear more about the challenges and opportunities of soil amendments, new and old.

Catch a new episode of The Agronomists every Monday night at 8 pm E!


  • Soil biological product trials were variable in Ontario. As can sometimes be expected
  • Manure is an important nutrient source and organic matter source
  • How long does elemental sulphur take to become sulphate? There’s no definite answer. Well the short answer is: it depends (on soil moisture, microbial activity, and fineness of the product!) It’s the one nutrient that some fertility pros would recommend spreading and leaving on the surface to transform
  • High pH soil on the other hand and using sulphur to acidify it… not economical
  • Back to the Envita product: cost of synthetic N is HIGH, perhaps some biological products can help out with N supply throughout the growing season
  • Cowan has meetings coming up to hash out when the product works and when it doesn’t work
  • As more sustainability programs come to the marketplace, something like Envita might be beneficial, as long as those environmental conditions under which the product works, can be determined
  • The first amendment, manure that is
  • Lots of macronutrients and micronutrients in manure, but also organic matter. Excessive levels of K aren’t great though, but for sandier soils… manure is magical?
  • Clip #1: Corn School: Managing manure while dealing with corn rootworm resistance
  • Regardless of where manure will be applied, it’s always a good idea to have it tested. It can be highly variable between livestock species and watch out for high N
  • Manure is a bundle of nutrients, so which nutrient do you need the most? Applying < 70 per cent of nutrient needs in the form of manure
  • Once that manure gets “revved up” it starts releasing a lot of nutrients, it’s a slow release though
  • Every manure type is different!
  • Predict fertilizer and manure requirements for next year’s crop, based on existing reserves in soil. Evaluate/audit your nutrient management planning. Then monitor!
  • C:N ratio of the manure? Not a great methodology to establish what they are, but if he had to speculate, 20:1 or higher
  • “We have to stop being comfortable with making fertilizer recommendations without soil tests.”
  • More soil testing, please
  • Would composted manure accelerate the rate of absorption?
  • Sulphur fertilizer addition to manured treatments (Jeff Schoenau’s work at U of S)
  • Cattle manure… the minute you start spreading cattle manure, you start to lose ammonia. In contrast, chicken manure is pretty much straight N
  • Adding manure to bite a chunk out of the fertilizer bill: with caution
  • Back to the “bundle of nutrients” concept

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The Agronomists (view all)Season 2 (2021) Episode 3

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