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Let There Be Lime

Somewhere around 14 million acres or more are affected by pH in western Canada, says Elston Solberg, senior agronomist with Agri-Trend, a fast-growing North American agricultural services company that began in Alberta.

Solberg was involved with Alberta soil fertility research in the 1980s. Today, he encourages clients to take a fresh look at the possibility of investing in improved soil pH.

In most cases, he says, only portions of a field need to be fixed with a lime amendment. The typical portion needing help is likely to be 30% to 40%.

Improved technology can easily map salinity on-the-go, with a sensor and a four-wheeler, he says. Some of the first new pH mappers began arriving in late 2012. The pH maps identify specific areas to treat.

Then, guided by GPS and variable-rate controllers, lime can achieve significant long-term, positive pH change, Solberg says.

“With a proper treatment, you can make that land more productive. You can do it once, long term, with tons per acre to move the pH a full unit, or you can do it annually with affordable precision applications,” he explains.

Solberg favors precision. “If we can apply lime annually to a very small width of application within actual areas that need to be treated, we can drive annualized costs down to between 7% and 9% or lower than the amount the old methods would use,” Solberg says. “We’re doing research on this now – creating a zone of alkalinity rather than treating the whole field.”

New Lime Options
Two high-calcium soil amendments manufactured in northwest Iowa by Calcium Products recently became available for western Canada. The products are mined, pulverized, and then pelletized.

SuperCal 98G (limestone) is 36% calcium with a 94% neutralizing value, while SuperCal SO4 (gypsum) is 21% calcium and 17% sulfur.

A group of Alberta agronomists formed ENR Distribution at Pincher Creek in late 2011 to acquire the sole distribution rights in western Canada.

Some of the first trials are under way in all four western provinces, in several soil types and cropping systems, on private farms, by retailers, and by associations.

In 2013, ENR applied a 600-pound rate of calcium sulfate (SuperCal SO4) to about 200 acres of white, hard, grow-nothing land in southern Alberta that had 26% sodium. It harvested 80-bushel barley on the treated area.

“We use the calcium sulfate form where pH is affected by magnesium or sodium. Where the pH is low due to lack of calcium, we use the more concentrated product,” says Terry Bonertz, ENR vice president and agronomy manager.

The point of the amendments, he notes, is to reach optimal pH and calcium levels. A significant increase in crop uptake of conventional nutrients can occur when the pH is optimized.

The old product, ag lime, was hard to work with.

“It was the consistency of baking flour,” Bonertz says. “Our lime is pelletized, easy to use. It can be shipped in Super-Bs, and it is able to be seed placed, banded, or broadcast. After it hits the soil and gets moisture, it reverts back to 200-mesh (powder) that is highly reactive in the soil.”

Close to home, in the first year, Bonertz was seeing a soil pH response of about 0.1 for each 100 pounds of product applied to the surface.

Two independent farm associations are beginning pH trials at Smokey Applied Research and Demonstration Association (SARDA) in Fahler and at Battle River Research Group in Stettler.

“SARDA has 44 plots in 11 different trials. It did both broadcast application and seed placed directly beside the seed,” Bonertz says. “SARDA testing is only in its second year and does show promising results.”

Researching Product Performance
Andrew Hoiberg, Calcium Products research and development director since early 2013, says SuperCal 98G came into production in the 1990s. Funded research to explore exactly how the products perform in soil is a recent focus.

“We’ve got a lot of research under way with universities and government agencies, and we hope to migrate that to Canada,” he says. “Plenty of studies tell you that you can get a yield increase on virtually any crop if you grow it in the right pH range.”

Hoiberg says his company’s product is more pure than traditional ag lime and has a finer grind. As a result, application rates can be substantially lower. In the Midwest, most applications are broadcast and guided by variable-rate maps.

Yield Boost
Eric Asare tested SuperCal 98G in one of the first independent trials. Asare works with Rack Petroleum Ltd., a farm supply and service company in western Saskatchewan.

On a 25-acre no-till farm site near Cutknife, Rack Petroleum hired a floater to apply rates of 300, 400, and 500 pounds per acre on five replicated plots with a range of 4.9 to 5.5 soil pH. The site was direct-seeded to soft white wheat. A normal good yield was expected to produce 85-bushel wheat on this farm.

The site had a good season. “The untreated control yield was 92 bushels an acre,” says Asare. “The 300-pound rate yielded 97 bushels per acre. The 400-pound rate yielded 100.7 bushels an acre. The 500-pound rate yielded 100.9 bushels per acre.”

The 400-pound applications increased soil pH by about 0.6 and offered the best return – nearly 9 bushels per acre. Cost for the product and application was about $57 an acre.

The 2014 crop on this site was field peas. Soil pH was increased, reaching an average of 5.9 pH by midsummer. Asare expects a pH plateau by early 2015, then a slow fade due to interactions with fertilizers.

“The product is working into the soil from the top and is having more effect as time goes by,” he says.

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