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Testing the calcium response

Cavalier Agrow is running field trials to test the agronomics of calcium

An independent ag retailer in northwest Saskatchewan is examining the agronomics of applying calcium. So far they’ve found the best yield response and economic return in the most calcium-deficient soils.

“As those calcium levels went up — no surprise — our returns came down,” said Greg Frey, location manager for Cavalier Agrow near Meota, Sask. Frey was speaking during Cavalier’s agronomy forum in the Meota area.

In 2017, Cavalier agronomists ran 16 trials in their trading area, which encompasses Medstead, Meota, Spiritwood and Meadow Lake, Saskatchewan. They applied NRG CaB, an ATP Nutrition product, at one litre per acre to canola on the second herbicide pass. NRG CaB is a foliar product that contains eight per cent nitrogen (N), 10 per cent Calcium (Ca), and two per cent boron (B). The product costs $7.70 per acre.

The overall average gain was one bushel per acre. But the average of all locations may not tell the whole story. For example, while Meota saw a 1.2 bushel gain with the calcium treatment, Medstead came in at 3.5 bushels. Medstead soils were also generally lower in calcium, Frey said.

The Spiritwood trials came in with a negative average overall. Frey said they always scratch their heads at negative responses until they can come up with an explanation, other than field variance.

Cavalier Agrow also saw some variation at the sites. For example, seven of the trials were conducted in Meota. Responses ranged from a low of -1.35 bushel per acre to a high of 5.66 bushels per acre. The field with the lowest calcium levels had the biggest yield response to the calcium treatment.

Frey said they see the same type of response with many nutrients, such as copper. Deficient soils will see a return on investment, he said. But not all soils are deficient, he said, and those soils won’t respond. The calcium trials showed that they need to concentrate on areas with deficiencies, he added.

The focus going forward will be putting NRG CaB in the right places, Frey said. They’ll also look at timing. They aimed to apply the product at the three to six leaf stage, but Frey said they were closer to bolting in most trials. By moving the application forward, they’d like to see if they’ll get a more consistent response, said Frey.

Why calcium?

Each year, Cavalier Agrow runs extensive trials to see if products work within the company’s trading area. The company’s trial program, branded as agPROVE, is designed to be professional, reliable, and repeatable, said Frey.

Agronomists start by looking at problems farmers face in their trading area and select products accordingly. They then design a protocol so that they can run each trial the same way at different locations, Frey said. This allows them to compile all the data into one data set, rather than having data from several different trials.

“Sometimes that’s highly successful and other times we run into stumbling blocks,” he said.

After looking at 10,000 different soil test points, agronomists concluded that many soils were calcium deficient.

“Calcium is one of the most important soil nutrients. If it’s not present at a great enough quantity in the soil, trying to balance out some of our other cations like potassium and magnesium can be extremely difficult, if not impossible,” said Frey. It also helps pulses with nodulation, and is a component in cell wall strength. Low calcium is also why many fields in the area have acid soils, he added.

How calcium deficient are the soils in northwest Saskatchewan? There are two ways to measure it. One is to look at base saturation, or what percentage of calcium is found on a soil particle compared to other cations. The optimal range is 65 to 75 per cent calcium, said Frey. From the soils Cavalier Agrow has collected, 20 per cent of soils are at 45 to 55 per cent calcium, and 14 per cent are below 45 per cent.

Another way to measure calcium is to measure the parts per million (ppm) in the soil. Frey said 2,500 ppm or greater is what they’d like to see. Only 18 per cent of the soils they’ve measured hit that optimum level. Another 16 per cent have between 2,000 and 2,500 ppm, leaving them in the marginal area. Another 27 per cent have between 1,500 and 2,000 ppm, and 40 per cent have less than 1,500 ppm of calcium.

Cavalier Agrow has also seen good results with another calcium product, ReLeaf Pulse. ReLeaf Pulse, also sold by ATP Nutrition, is an agPROVE alumnus, having yielded a 3.3 bushel per acre advantage in those trials.

“The bulk of our pea herbicide today goes out with ReLeaf Pulse for that reason,” said Frey.

However, ReLeaf Pulse is a four per cent calcium product. Frey said they wanted to see if the 10 per cent calcium in NRG CaB boosted yields and returns further. So in 2017 they started running trials comparing ReLeaf Pulse to NRG CaB, with no untreated check.

“We had a 2.35 bushel an acre advantage with NRG CaB over ReLeaf Pulse,” said Frey. The average return on investment over ReLeaf Pulse was $14 per acre, once they’d factored in the product cost.

In 2016, they also ran one trial that “sparked their interest” in going forward with NRG CaB, said Frey. That trial was on a field that had been extensively soil tested as part of their iFarm program. The base saturation of calcium, at 52 per cent, put it on the marginal end.

The field also came in at “1,394 parts per million, which put that field in the deficient (zone) for the actual calcium in the field,” said Frey. “And we had a five bushel response. So that’s why we went forward with NRG CaB to this year.”

About the author

Field Editor

Lisa Guenther is field editor for Grainews based at Livelong, Sask. You can follow her on Twitter @LtoG.


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