KEY PRACTICE: Most Prairie soils are not short of potassium, and canola rarely responds to applied potassium fertilizer. When checking for deficiencies, note that cereals will show symptoms long before canola.
KEY RESEARCH: R.J. Soper, University of Manitoba. “Soil tests as a means of predicting response of rape to added N, P, and K,” 1971, Agronomy Journal 63: 564-566.
Most canola crops grown in Western Canada are not short of potassium because most Prairie soils have sufficient potassium levels. Sandy soils with low clay content are most likely to be short of potassium, especially if those fields have been in forages where a large percentage of the biomass is removed each year.
Cereals in the rotation will show signs of potassium deficiency long before canola does. Cereal symptoms may start to show when soil potassium levels drop below 300 lb./ac., which is well above the critical point for canola.Open the PDF to read the entire research summary from the 2014 Science Issue of Canola Digest
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