Making the most of data | Growers cannot maximize yields without a better understanding of soil nutrients
Learning how to read a soil test is critical for farmers who want to significantly increase crop yields, says a South Dakota grower.
“I challenge you this winter, learn how to read this thing,” Brian Hefty of Baltic said Feb. 18 at the CropConnect conference in Winnipeg as he pointed to a soil analysis report from his PowerPoint presentation.
“Spend an afternoon at it…. This is a $1,000 an hour job.”
Hefty and his brother, Darren, host a daily radio show on Sirius XM called Ag PhD, where they share information on agronomics, farm profitability and environmental stewardship.
Read Also
Agriculture ministers agree to AgriStability changes
federal government proposed several months ago to increase the compensation rate from 80 to 90 per cent and double the maximum payment from $3 million to $6 million
The Heftys have grown 300 bushel per acre corn and their soybeans regularly top 70 bu. per acre.
Hefty said only a small percentage of producers understand soil test data, and fewer recognize that it is vital information for the pursuit of higher yields.
For example, he said the crop cannot efficiently use fertilizer applied to the soil if pH levels are too low or too high.
“Phosphorus is a good example,” he said, pointing to a chart showing how phosphorus availability declines as soil pH rises.
“You might get (a) recommendation from your agronomist and he says, ‘go put a bunch of phosphorus out there’…. So you figure, go broadcast that phosphorus out there and bam, now we’re in good shape. But the problem is, you might have 50, 60, 70 percent of (it) tied up…. The more you can get your soil pH to about neutral, which is about seven, the better off you are.”
Percent base saturation, which is the proportion of potassium, magnesium, calcium, hydrogen and sodium to each other, is also worth considering.
He said farmers in the Red River Valley are frequently told their soil has sufficient potassium so it’s unnecessary to apply the nutrient.
“(But) in southern Canada and in the Midwest, we’ve got really high levels of magnesium in the soil. We have really high levels of calcium in the soil,” he said.
“We have pretty good levels of potassium, but it’s not in balance with our magnesium and calcium.”
Hefty said potassium is critical because a deficiency will cause crop lodging.
“If you’ve ever had a crop fall over, I don’t care if it’s wheat, corn, soybeans, canola … chances are it’s a potassium issue.”
Terry Buss, a Manitoba Agriculture farm production adviser in Beausejour, said potassium and phosphorus deficiencies in eastern Manitoba have increased grower interest in soil tests and analysis.
He said producers in the region, particularly those on tight soybean rotations, haven’t applied sufficient quantities of those nutrients, which has led to a deficit.
Some soybean growers have recognized their mistake and are responding to the nutrient shortage, Buss added.
“This fall, given the large crops we had, I’ve seen more interest in soil tests than I’ve seen in a long time,” he said.
“More people are rushing to figure out, ‘how do I return this fertility (because) I’ve emptied the bank.’ ”
Rigas Karamanos, a senior agronomist with Koch Fertilizer Canada, agreed that soil tests are essential to understand fertility.
However, growers must realize that all soil tests are not created equal.
“Your soil test is an inventory. You get these numbers, now what the heck do they mean?” he said.
“You can send (soil) to five different labs and get five different answers. Now what?”
In a 2005 paper, Karamanos said there are 11 ways to determine soil pH, multiple methods to assess electrical conductivity and several approaches to calculate soil organic matter.
“(As well), there is a common misconception that soil test levels represent ‘plant available’ nutrients,” he said.
“Soil testing is searching for nutrient forms that are ‘potentially’ available to plant roots. Therefore, soil tests … become meaningful only after they are calibrated against crop yields.”
Hefty emphasized soil testing and analysis in his presentation, but he said it represents one piece of the puzzle when it comes to attaining higher yields.
If a grower wants to double yields, for instance, it comes down to commitment.
“Most people are going to say, ‘I don’t know if that (doubling yields) is even possible,’ and they limit themselves right away,” Hefty said.
“It’s absolutely possible…. It’s attention to detail … and the diligence to stay with it year after year.”
