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Soil SOS

Your soil is alive. What is it trying to tell you?

Tillage blackens soil. There are immediate benefits, for tillage warms and dries soil to prepare for planting. Later perks? Not so much. Each tillage pass slashes through soil aggregates and breaks soil structure. Soil also gets thrown out of balance as it loses its structure and moves away from native prairie state.  

Since the prairies were first plowed, soil carbon stocks have decreased by 40% to 50%, says Catherine Stewart, a USDA-ARS research soil scientist. Soil carbon is a component of soil organic matter, which consists of plant and soil animal materials in various stages of decomposition. The basis of soil fertility is organic matter. Under ideal conditions, soil microbes can release nutrients like nitrogen to crops. Lost soil organic matter decreases both nutrient cycling and habitat for soil microbes.

Carbon is also critical for soil function. It keys a soil’s water-holding capacity, plays a role in forming soil aggregates, and reduces erosion. Managing soil carbon can also enhance productivity and environmental quality.

“Soil carbon is really important,” explains Stewart. “If there’s one thing you can do for your soil, you should try to increase your soil carbon.”

Be patient. At best, efforts to boost soil carbon will take at least five years to show benefits. Benefits could even take 15 to 20 years, says Stewart. Still, carry on. Adopting no-till will increase your carbon stock, earthworms, and soil life. It’s a long-term investment, she says.

What should you do?

“We’ve known for a long time that no-till does great things for carbon levels,” says Stewart. “We’re losing tons of soil due to erosion through tillage. No-till helps to make soil more resilient.”

“Erosion is a huge problem in our region,” says Abbey Wick, North Dakota State University (NDSU) soil health specialist. In 2014, David Hopkins, an associate professor at NDSU and Brandon Montgomery, a graduate student, conducted a study throughout eastern North Dakota where topsoil depths were sampled and compared with samples collected from those exact locations before the 1960s.

The results were staggering. The scientists found there had been a loss of up to 15 inches of topsoil in the last 50 years. “We’ve lost between 1.2% to 2.5% soil organic matter during that time,” says Hopkins.

To compound the issue, topsoil is the part of the soil that has the most carbon, says Stewart.

“The subsoil material that has lower fertility and contains the salts that can cause issues with crop production in our region is much closer to the surface than it used to be,” says Wick. “This creates challenges. When topsoil is lost, your soil also loses the ability to respond to extreme weather events.”  

To mitigate these losses, you can take the following three management steps.

  1. Reduce soil disturbance. Tillage directs the soil where to fracture, says Wick. That forced fracture damages the roots and the fungal community that holds the soil together. “Tillage disrupts everything that was built during the growing season,” she says.
  2. Manage residue. Start with residue management out of the back of the combine; it’s the easiest to adjust. “Residue management is free,” says Wick. “You don’t have to purchase anything. Just manage the residue coming out of the combine. Make sure you can plant into it or add a vertical tillage pass the next year if you’re concerned.”
  3. Cover the soil. Especially if you deal with sandier soils, Wick encourages the use of cover crops to build soil structure and organic matter to reduce erosion.
    Abbey Wick Cover Crops
    –Abbey Wick, NDSU

“These beneficial practices are difficult to generalize,” says Stewart. “These practices are likely to work, but there are situations where, from an economic perspective, they may not work. It’s going to be important to think outside of the box.”

The more you can get your soil back to a native system, the better off your soil will be. “There are trade-offs,” explains Stewart. “In some cases, there are yield hits. Even with continuous no-till, it may still not be yielding quite the same. The devil’s in the details.”

There’s no shortcut to increase the health of your soil. The safest bet, though, is to do as much as you can with a single pass, cover the soil, and minimize disturbance, she says.

There are developing technologies that may potentially assist farmers as they strive to boost the health of their soils. Below is one of these.  

Adding soil carbon

An engineered biocarbon technology, used in Cool Terra and developed by Cool Planet, is one option for farmers looking to increase soil carbon. It has the ability to boost crop yields and provide environmental benefits by sequestering carbon and improving soil health, says Wes Bolsen, head of global business development and external affairs for Cool Planet.

“Biochar, which is a raw input material, has had mixed results,” explains Bolsen. “It’s a cooked-down biomass to a stable form of carbon, and it’s put back into the soil.”

Biochar, unlike engineered biocarbon technology, is not posttreated. “By engineering the biochar, we make it more useable and valuable for agriculture,” he says. “That’s why biochar hasn’t been widely adopted. We don’t even call our product biochar.”

Cool Planet cleans, or posttreats, the biochar by adjusting the pH, flipping it from hydrophobic to hydrophilic, and removing hydrocarbon residues and other toxins. It’s engineered to a specified consistency and size.

“Farmers demand consistency. They want it to look, handle, and act the same every time,” says Bolsen. “Then they want to know the technical side of it as well, such as, what it does, how it works, and the application rate. With this, we can confidently provide those answers.”

Sequester carbon

“We’ve put carbon back in the soil with engineered biocarbon technology to promote microbial life through soil organic carbon that stays in the soil,” says Bolsen. “It has the half-life of roughly 400 years, which means it’s truly sequestered carbon being put back in the soil. Its porosity and utility promote microbial life and hold on to moisture and nutrients that remain plant-available.”

This is a stable form of carbon, he says.

“Think of it as a home for the microbes to live,” says Bolsen. “It’ll provide water and nutrients to those microbes.”

This differs from just adding compost or additional soil organic matter that quickly decomposes to the soil. “We’re putting a long-lasting structure back into the soil and increasing crop productivity,” he says.

He sees a future where engineered biocarbon technology would not only increase carbon in soil but also be a carrier of microbes to the soil. That’s what they’re working on today.

For corn, soybeans, and wheat, Cool Terra can be applied with the seed. In the past, Cool Planet was focused in specialty crops. However, through distributors, it is available for production ag at the commodity crop level. For row crops, industry pricing is around $11 to $15 per acre for applications made at the time of seeding, varying by soil type and application rate.

“Engineered biocarbon technology can be another tool in the toolbox,” says Bolsen. “There are cover crops, crop rotation, and other ways to build soil organic matter and increase soil health. This is going to be another tool for rebuilding soil.”

Alternative Soil

The agriculture industry has been innovative, and solutions in other markets have become fruitful. Phytelligence, an ag tech start-up, developed a system of growing fruit, nut trees, and berries in a gel.

The nutrient-rich gel has a composition specific to each variety of fruit, but it primarily consists of a gelling agent, carbon source, and essential macronutrients, micronutrients, and growth regulators, says Amit Dhingra, founder and CSO of Phytelligence.

Phytelligence
Phytelligence

While the fruit industry is significantly different from row-crop production, this type of innovation shows what’s possible in the future.

The average root-to-fruit process takes 10 to 12 years. Phytelligence has cut that time in half. It’s able to supply orchards with fruit-producing plants in a mere five years, while reducing risk of disease and increasing water efficiency.

The traditional growing process for fruit trees starts at a rootstalk nursery. The nursery prepares these trees. The rootstalks are harvested after four to five years and stored in cold storage before they ship to a finished tree nursery. At this nursery, the tree is grown for another one to two years and the buds from the desired variety are grafted to the tree. Then, the tree, after another one to two years, is removed one last time and placed in cold storage before being sent to the orchard.

The Phytelligence process, called MultiPHY, starts with the virus-free material in custom-formulated initiation gel. It’s then transferred to multiplication gel, then shoot-elongation gel, and then transferred to a custom-formulated rooting gel. Finally, the plants are placed in rooting sterile potting mix. Within five years, the trees are delivered to the orchard.

“We develop the gel for each variety,” explains Dhingra. “We can produce millions of trees in one to two years.”

Because the plants are grown in a controlled environment, they aren’t exposed to the soil pathogens that cause disease.

The use of this nutrient-rich, gel-based process reduces the need for pesticides and fungicides during the production of starter trees while being more energy efficient and water saving, he says.

“Our process reduces the risk for the farmer,” says Dhingra.

Will this technology directly impact row-crop production? He isn’t so sure, though there are hypothetical situations where it would work in theory, he says.

Should there ever be a disease that affects row-crop plants during germination, the seed could germinate in the gel before planting.

That, however, seems far-fetched at this point, Dhingra says. Yet, in a world with limited amounts of arable land and an expanding population, these technologies may play a larger role in the future, he says.

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