MOOSE JAW, Sask. – Canaryseed growers often report higher yields when they apply potash to their fields.
Researcher Bill May wanted to know if it was the potassium or the chloride in the fertilizer that made the difference.
After two years of study, it turns out it was chloride, he told farmers at the Indian Head Agricultural Research Foundation’s annual winter seminar last week.
May examined results from plots with no potassium or chloride, potassium chloride, potassium sulfate and calcium chloride.
Plots were planted in six Saskatchewan locations, including sandy loam and oxbow loam soil and Regina heavy clay, as well as Stewart Valley, Nipawin and Indian Head.
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May said he needs more data, but the crop clearly responded to chloride in the dry conditions of 2007 and again under better moisture conditions last year, particularly where soil residual chloride was low.
“Under extreme drought conditions, under less than ideal fields, we had a response to chloride,” he said of the plots in sandy loam.
“In 2008 we had a high yield response.”
The plots with chloride showed less seed abortion and more filled heads.
“You can’t tell the difference between the plots until we actually have grain failing occurring and the heads that are filled are bowed over and the heads that aren’t are standing up straight,” he said.
On the oxbow loam site, the conditions were similar and so were the results. The potassium chloride plot at that site produced nearly 40 bushels per acre in 2008, showing that the crop will respond even in high-yielding good moisture conditions.
All the other sites showed no response. May said heavier soil, on which farmers normally grow canaryseed, is not usually low in chloride.
“I don’t yet know the probability of a grower getting a response to chloride,” he added. “We don’t have enough data.”
He suggested producers soil test for chloride. Ten kilograms per acre or lower at a depth of 60 centimetres would be a low test result. May also cautioned against too much chloride. His study used 10.5 kg per acre.
He said producers should be wary of heavy crop stands that produce biomass but less seed.
“If you have a hay crop, you should be much more concerned.”
