The measure of soil health

A farmer who is his own customer has a unique opportunity to walk the walk.

That’s especially true for Mitchell Hora, a seventh-generation farmer in Washington County, Iowa, and founder of Continuum Ag. His consulting company offers a software platform that collects soil metrics for organic matter, nutrients, and CO2, and then establishes health benchmarks.

With this technology, Continuum Ag creates a data-driven road map for farmers to improve their soil and profit margins. Hora and his family have done the same at home. They raise corn, soybeans, cereal rye, barley, and mustard on their 700-acre no-till farm.

“This year, we have about 125 different field trials. We do intense data collection via real-time soil sensors, weekly soil
sampling, and aerial and drone imagery,” Hora says.

Quantifiable and qualitative soil health data are key to lowering the risks of adopting new sustainability practices. 

Therefore, the first step toward your own sustainability system is establishing a baseline of information. Measuring carbon, organic matter, biological activity, nutrient availability, and nutrient efficiency will set you up for the future.

“Getting a better understanding of your farm is the best way to reverse-engineer your goal,” Hora explains. “I may want to sequester carbon, improve the nutrient density of my crop, or increase profitability on every acre. How I do all of that starts with an analysis of the farm.”

New markets may demand that farmers implement additional sustainable practices, but Hora is quick to bring the focus back
to economics.

“There is long-term profitability to be had by implementing soil health systems, but it has to be based on data so you can make reasonable, incremental changes at the beginning,” Hora explains. “Every farm can improve nutrient efficiency by 10%. You could add one more cover crop into the blend or add another split application of nitrogen – logical improvements.”

Enhancing Soil Health

Michael Vittetoe, a fellow farmer in Washington County, has worked with Continuum Ag for the past several years.

The Vittetoe farm is multigenerational; his father and sisters are involved in the operation. They have about 1,400 acres of corn, soybeans, and cereal rye in a relay cropping system.

Their farm has been no-till since the late 1980s. Vittetoe recognizes this was a unique and powerful strategy for his father and others in their southeastern Iowa community to have implemented.

“Soil health isn’t really new in this area, but now we’re escalating it by going from no-till to cover crops and incorporating other strategies,” Vittetoe says.

In 2011, the Vittetoes dedicated just 40 acres to test cover crops. In 2015, they expanded cover crops into additional fields. Now they cover crop every acre going into soybeans and a third of the acres going into corn. Vittetoe calculates it at 850 acres of rye ahead of their 2020 crop.

“One of our fields, up until about 20 years ago, formerly had hogs and cattle, and has since been corn-on-corn for us,” Vittetoe says. “It always produced a good crop, but in 2018, we started playing around with interseeding a 17-way mix into the corn.”

At first, their corn yield suffered from the competition, and early soil tests – such as Haney, Mehlich, and
Bray – didn’t indicate many positive numbers.

In the second half of the growing season, however, Vittetoe and Hora started to see results. Continuum Ag pulled soil tests on the field every two weeks and realized the potential was in the soil all along, but it was the cover crops that made the difference.

“One key finding from Michael’s data is the incredible increase in plant-available nutrients with diverse cover crops,” Hora says. “We freed up over 1,000 pounds of phosphorous per acre with the enhanced biology.”

“When we saw the nutrients get unlocked in the soil from the 17-way mix and how our soil health improved, we realized we could have been doing more. The answer was to bring cattle back,” Vittetoe says.

Having seen neighbors implement grazing systems, he knew that livestock would open up potential for direct marketing, cover crops could work double-time as forage, and the manure would contribute biological benefits.

“I have mixes I establish in the fall, spring, and middle of summer. In total, there are about 40 different plant species growing,” Vittetoe says. 

The Vittetoes continue to find ways to improve their soil. Even now, they are analyzing the commonly overlooked calcium levels in the heavy prairie topsoils to determine how to enhance their productivity.

Measuring the Immeasurable

While strong management decisions are often based upon data, some results can’t quite be backed by the numbers.

Vittetoe says that beyond soil health tests, just putting two and two together helps validate the practices in place.

One of those indicators is significantly reduced herbicide costs. Now that rye is planted on every acre ahead of soybeans and they delay termination until June, the Vittetoes have completely cut out the preemerge residuals, saving $20 to $30 per acre.

With this management strategy, they see very little weed pressure. In addition, their soil is more capable of storing water after repeated bouts of 2- to 3-inch rains.

“You have to actively manage your crop decisions every year. It isn’t a cookbook way of farming,” Vittetoe says. “The savings and benefits tell me we’re meeting the needs of the soil for it to function properly.”

Popular soil health tests

Test Highlights Pros Cons Cost

Phospholipid Fatty Acid (PFLA)

Results show microbial diversity in fungi and bacteria

  • Detailed analysis
  • May detect soil health changes over 1-3 years

Labs vary on the fatty acid markers for microbes

$50-$80

Haney

Uses alternative chemical extracts to determine plant- and microbe-available nutrients

  • Offers fertilizer recommendations
  • Widely available

Fertilizer rates may differ from university
recommendations

$40-$50

Solvita-CO2 Burst

Examines microbial health by measuring CO2 from microbial respiration once dry soil is rewetted

  • Fast analysis
  • Widely available
  • Typically packaged with other tests
  • Results are extremely variable

$20-$30

Source: University of Minnesota Extension

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