Potassium generally gets more attention than chloride, but new research shows chloride can really increase canaryseed yields
Saskatchewan has half the world’s potash reserves and typically produces 30 per cent of the global supply, according to Saskatchewan’s Ministry of the Economy. Potassium chloride is the most common potash type used. While both potassium and chloride are essential plant nutrients, concerns over potassium levels often trump chloride. But new research shows chloride elicits a significant yield response from canaryseed.
Chloride affects many plant functions, such as photosynthesis, disease suppression, enzyme activation, nutrient transport and stomata activity. Dr. Jim Beaton, a soil scientist and senior agri-coach with Agri-Trend, says chloride also affects plant development.
“It’s been shown that chloride deficiency lowers the rate of cell multiplication in the leaf, and this slows down growth ultimately in the leaf area,” says Beaton.
“But traditionally attention was only paid to the potassium. And occasionally, of course, there was some concern about the chloride, perhaps where there might have been problems. But in, fact, chloride was pretty much regarded as a nuisance,” Beaton says.
“And our soil scientists, agronomists, felt that natural supplies in the soil were generally sufficient.”
Plant sensitivity to chloride seems to vary greatly. Beaton says some plants, such as certain legume and soybean varieties, are more sensitive to excess chloride than others.
Researchers have studied chloride’s effect on wheat, barley, and oats, but effects have differed between studies and varieties. New research shows canaryseed consistently responds to chloride by yielding higher.
Canaryseed yields rise with chloride
Canaryseed yields have been shown to increase over 20 per cent with chloride application.
“We had a preliminary experiment back in 1999, 2000, and 2001 where we seemed to get some kind of response from potash. And we had anecdotal comments from growers that seemed to be saying they got a response from potash. And so we decided we’d better find out if there was a response from potash and whether it was chloride or potassium,” says Dr. William May, crop management agronomist with Agriculture and Agri-Food Canada.
From 2007 to 2009, researchers conducted field experiments at Indian Head, Carry the Kettle, Regina Plain and Stewart Valley, Sask. The experiments included both hairless and hairy canaryseed varieties.
May and his colleagues applied several treatments to canaryseed to see whether potassium, chloride, or both would trigger a response. Chloride rates ranged from 8.1 to 24.4 pounds per acre. Potassium ranged from 8.9 to 26.8 pounds per acre. Some plots were also treated with potassium-only and chloride-only applications, to gauge which nutrient created the response.
Potassium-only treatments didn’t trigger higher yields than plots that received no treatment. But researchers saw a yield jump of 24 per cent after applying chloride.
“We sometimes get an increase in kernel weight, but most of the increase seemed to be because we were retaining more seed panicle,” says May.
Both the hairless and hairy varieties of canaryseed responded to chloride.
When other crops do respond to chloride, often the differences are apparent before seed filling. For example, researchers have observed a response in winter wheat between the boot and flowering stage. But canaryseed doesn’t follow this trend.
“In canaryseed the response is very consistent. And in canaryseed you will not see any difference between treated and untreated canaryseed until seed filling starts,” says May.
May says he doesn’t know whether the yield bump comes from less stress, fewer abortions, or increased fertility. What makes canaryseed more sensitive to chloride deficiencies than any other crop is also a mystery.
The crop’s response was similar whether the application rate was 8.1 or 16.2 pounds per acre. Canaryseed also responded when residual chloride levels in the soil were as high as 72.3 kilograms per hectare, May says.
May is working on a chloride response curve for canaryseed, but hasn’t analyzed the results yet.
“But as of right now, I have to recommend that canaryseed growers just use 18 pounds per acre of potash, unless they have residual chloride in the soil in the top six inches that’s 90 or 100 kilograms per hectare or 80 to 90 pounds per acre.” †