Eco-Ag, Day 3: John Kempf Slays Soil Science Sacred Cow

On the third day of the 45th annual Acres U.S.A. Eco-Ag Conference, John Kempf took aim at one of the foundational tools of modern agriculture — the soil test.

Kempf is the founder of the Advancing Eco Agriculture consultancy and the host of the Regenerative Agriculture podcast. One of the most the most influential figures of regenerative movement, the Amish Ohioan is a mainstay of the Eco-Ag Conference.

And so it was with some trepidation on Wednesday that Kempf spoke for the first time publicly about his deep misgivings regarding one of the orthodoxies of agriculture for the past 70-plus years.

Armed with more than 1 million data points gathered over the past decade, he declared that a chemistry-based method of soil analysis “has led agriculture astray.” Comparing soil test results with plant sap analysis data over the years has pushed Kempf to a surprising conclusion: Traditional soil analysis does not correlate to plant nutrient absorption, nutrient density or crop performance.

The title of Kempf’s presentation was “Soil Test 2.0” and he laid out a compelling case against the over-reliance on soil tests that reveal the balance of nutrients in a soil — inorganic minerals such as calcium, nitrogen, potassium and phosphorous.

Chemistry, Kempf explained, is only one part of a healthy soil. Other factors include geology, structure and biology. All of these things must be taken into account — particularly the biological dynamism of a soil, he said.

“We can not make reasonable and effective agronomic recommendations from soil analysis with mathematical calculations alone,” he said. “The nutrients plants actually absorb is what matters.”

In the 1930s, Dr. William Albrecht developed the principles behind what is known as the Base Cation Saturation Ratio (BCSR) analysis. These techniques and principles were hailed as a breakthrough, particularly by Acres U.S.A. founder Charles Walters. And, in fact, they allowed agronomists to realize strong crop responses for decades.

That no longer seems to be the case, Kempf said.

That might be because soils are no longer as biologically active as they used to be. Kempf hypothesized that this could be the result of soil compaction from the use of heavy machinery and the indiscriminate application of pesticides and herbicides.

Regardless of the cause of the decline, Kempf outlined what he sees as a new paradigm for agronomy:

  • The nutrition plants actually absorb from the soil is the final indicator of what the soil can actually supply.
  • If soil analysis correlated with plant nutrient absorption, then nutrient excesses in soil would be high in plants and nutrient deficiencies in soils would be deficiencies in plants. Neither is true.
  • The only nutrients which generally correlate between soil analysis and sap analysis are sulfur, zinc and boron.
  • Potassium applications drop by 70%.
  • Nitrogen applications drop by 60%.

“If your crops produce high yields, of exceptional quality, and are disease and insect free — do you care if your soil analysis report is ‘ideally balanced’?” he asked. “Plants are the ultimate report card.”

Nicole Masters

Keynote speaker Nicole Masters, an agro-ecologist hailing from New Zealand and the author of For the Love of Soil: Strategies to Regenerate Our Food Production Systems, followed Kempf. She wasn’t as concerned with slaying sacred cows as she was with what they might deposit in the soil.

Expanding on Kempf’s insights on a balanced approach to soil health, Masters emphasized that biological function is what drives plant performance and health.

The microbial life in the soil is what builds what Masters called an “underground metropolis.” More than 80% of plant health and nutrition, she said, is driven by biological function, diversity and networks.

Masters also went deep into how an understanding of plant and animal epigenetics could benefit farmers and ranchers. In short, the concept is, you are what your mother eats, she said. Put in plant terms, that might mean inherited traits for drought resistance, seed dormancy and biological relationships.

Epigenetics also means inherited trauma. Pesticides and herbicides, for example, can alter over 600 genes in a plant, genes that are responsible for plant defense and for building strong cell walls. Those biocides, along with synthetic fertilizers, can also shut down communication mechanisms in plants and the microbes and invertebrates in the soil.

Bugs, Masters said, can be your greatest allies. They play a role in decomposition, nutrient cycling, pollination, seed dispersal and building soil structure. They are often food for higher organisms and can act as biological controls within an ecosystem.

In conclusion, Masters offered up several keys to lifting plant and biological signaling, the means of exchange that enables nutrient-dense crops.

  • Optimize brix and reduce plant stress
  • Diversity, diversity, diversity (plants, animals and microbes)
  • Provide diverse food for microbes
  • Address any major macro/micro-nutrient imbalances
  • Use practices which build carbon and water holding capacity

Marty Travis

Marty Travis, who runs Spence Farm in Illinois, started the day on an optimistic note by describing how he has banded together with 60 other farms to nourish communities in his region while thriving during a pandemic.

Travis, the author of the Acres U.S.A. book My Farmer, My Customer, leads a collective of farmers that used to serve some of the top restaurants in the Chicago area. In March, when the COVID-19 shutdown began, instead of having 35-40 restaurants on their delivery list, the group found they had three. And though the restaurants were shutting down, some for good, they didn’t forget about Marty’s group. The chefs put out the word to their customers that there was fresh food for sale. The demand from families and individuals was so high that the group saw a big spike in its usual revenue. The added labor of sorting hundreds of orders, however, proved to be a challenge and led Travis and his group to a new idea and opportunity.

Travis teamed up with Matt Wechsler — a filmmaker who feature Travis in his 2016 documentary, Sustainable — to open Village Farmstand, a one-stop shop in Evanston, Illinois, for customers of Travis’ farmer network. The group is also partnering with Chicago-area nonprofits to get fresh food into underserved communities.

Travis is now looking to replicate this model across the country.

“There is this whole climate of cooperation, of compassion, of caring,” Travis said.

Rockey Farms Field Tour

Brendon Rockey of Rockey Farms in Colorado gave the audience a tour of his potato operation, and how he introduced more than 40 species into his fields to help with soil health, pest control, weed mitigation and nutrient retention.

"I choose to invest in my soil," he said. 

— Ben Trollinger, Acres U.S.A. editor.

All Eco-Ag Conference Highlights

The 2020 Eco-Ag Conference ran from Dec. 1 to Dec. 4. Here are the highlights of each day below:



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