The Role of Boron in Canola

Boron is one of the two micronutrients Prairie growers need to pay attention to when growing higher yields of canola.

If you are targeting 40 bu/ac canola, you usually don’t need to worry about micronutrients.  If you’re targeting 60 bu/ac you often need boron and when you’re after 80 bu/ac you will likely need it.

When you’re intending to grow high yields of crops, a possible analogy is to think of your crop as a high performance race car engine and the nutrients needed as the high octane fuel required so the engine performs at its optimum potential.

Similarly, if you are already investing a lot in your canola crop by putting down high rates of the macronutrients don’t then limit yield by not applying micronutrients such as boron.

While a high-end fertility program does not guarantee higher yields it does significantly increase the probability of obtaining higher yields over average fertilizer programs.

Agronomists generally suggest that for canola you want 2 lb of boron per acre in your soil or 1.0 ppm on a 0-6” soil sample but there are a number of aspects to boron that can affect this recommendation. 

  • Soil boron is extremely variable across a field so while your field’s average soil boron level may be sufficient, a large number of acres can be deficient.
  • The boron soil test is the ‘poorest’ of all the nutrient analyses done by a lab, so there is always the worry that the soil test results are not accurate when soil boron levels are ‘low’.
  • Soil B is mobile and leaches with rain, so with ‘good’ rainfall you can have the soil boron below the canola plant roots and flowering (the high boron demand period) starting.
  • In ‘good’ moisture years when the yield potential is high, thus the demand for boron is higher, the plant gets the moisture it needs closer to the plant root. As most of the boron taken up by the plant occurs during water uptake, ‘good’ moisture years can produce a temporal (or temporary) boron deficiency during flowering, the worst time for the plant to be deficient in boron.

When you do need to apply boron, these are your options:

  • Granular boron or liquid boron soil-applied (but not seed placed) with other fertilizer
  • YaraVita PROCOTE™ B impregnated onto your granular fertilizer and soil-applied
  • Foliar boron applied prior to the 10% bloom stage of canola

Note, given that it takes quite some time for boron to move from the foliage to the destination tissue, Yara agronomists recommend it be applied no later than 10% bloom, i.e. usually with the herbicide.


There are other key nutrients for foliar application that aid in optimizing yield in canola, alongside boron:


Watch this video about the benefits of foliar nutrition in canola.


Boron deficiency in canola

Low boron can lead to cracked, hollow stems, poor seed set and yield loss. The picture below from a trial in Manitoba showed the boron added, created a 7 bushel/acre yield response. SRP on BORTRAC 150 is less than $3/acre - an extremely cost effective application. Add in to herbicide or fungicide at 0.4L/acre.

Listen Now: Your Crop Requires More Than Just Macronutrients

Listen Now

In interview to Real Ag Radio on March 28, 2019, Yara's Crop Manager Markus Braaten talks about the critical role each micronutrient plays in producing the best possible crop.