Boron and other micronutrients: Economic results are rare

September 27, 2017 - Issue 27

When well-designed research studies are done for micronutrients in canola, results show little if any economic benefit.

The Canola Council of Canada boron trials as part of the Ultimate Canola Challenge in 2013-15 found no consistent yield benefit from boron treatment, including in those plots with very high yield results.

When heatwaves and flowering coincide, boron is often touted as a remedy, but when Alberta Agriculture oilseed specialist Murray Hartman ran his meta-analysis of boron studies, results showed no relationship between boron response and temperature. In short, analysis showed no boron response – even when temperatures were hot at flowering.

What about other micros? Whole plant tissue analysis of canola at flowering shows micronutrients levels are sufficient at these levels: 29 parts per million for boron, compared to 19 ppm for iron, 14 for manganese, 14 for zinc, 2.6 for copper and 0.02 for molybdenum.

Iron deficiency is rare for canola and most other field crops on the Prairies. A deficiency in copper is more likely to show up in cereals before canola. Manganese deficiency will show up first in oats. Zinc deficiencies will show up first in alfalfa, flax and beans before canola. Some bean growers in southern Alberta will add small amounts of zinc, particularly on sandy soils. Correcting any evident shortages in these other crops should take care of any potential deficiencies in canola. Molybdenum is more likely to show up in canola before any other crop, but molybdenum is needed at very low levels and deficiencies have not been observed in canola on the Prairies.

Impetus for this micronutrients discussion came from this recent Alberta Farmer article. We agree with Ross Mckenzie and have fixed the text in this older Canola Watch article to eliminate any confusion with regard to boron.

Further reading:

Boron: Understanding the soil test
Micronutrients? Take care of macros first

Canola Watch