Berns cites ‘seven keys to healthy economy’
GEORGETOWN, Del. (March 6, 2018) — Keith Berns of Green Cover Seed in Bladen, Neb., thinks of the complex system of interactions between plants and living organisms in the soil as the economy of a country.
“Economies are intricately interconnected and interdependent. You can’t mess with one part of this economy without messing up another,” he said during the Delaware Soil Health Partnership’s workshop on Feb. 21, focused on the profitability of soil health.
Berns listed seven keys to a healthy economy: supply, demand, currency, capital, energy and resources, infrastructure and defense/protection.
Supply is something you can sell. Plants use carbon dioxide and water to produce glucose and oxygen through photosynthesis. In that glucose is carbon, which is essential to life and therefore very much in demand by living organisms in the soil, from fungi, bacteria and nematodes on up to earthworms and other creatures.
Currency allows exchanges between producers and consumers, and you need it in different forms such as cash, credit and savings bonds. In the soil economy, carbon is the perfect currency. It can be collected, spent or saved and is desired by all members of the economy.
Plants use the carbon molecule to “purchase” things. They pay it out through root exudates. “You can see liquid carbon dripping out of roots,” Berns said. More than half of the carbon a plant produces is not used to grow plant tissue but is traded in exchange for something from soil life.
“Plants are not stupid,” he said. “They only exude if they can get something in exchange. They don’t give the carbon away.”
The fourth key is capital — stored or saved currency, which is needed for growth and stability. “You cannot accumulate capital if you can’t pay your bills,” Berns said, and a plant can’t build organic matter if it doesn’t have excess carbon.
Corn and soybeans grow all the carbon they need, but farmers export much of it at harvest. “That’s like living paycheck to paycheck,” Berns said. “You can get by, but you don’t have the ability to withstand tough times or a disaster.”
Cover crops are important because they put carbon into the soil.
“On our farm, when we started no-tilling, the organic matter was about 1.6 to 1.7 percent. After 20 years of no-till, it was 2.6,” Berns said. “Just seven years after we started cover cropping, it’s up another three-quarters of a point. We’re introducing excess carbon into the system.”
Energy drives the economic system, but it is expensive. Leaving soil bare, not planting a cover crop, is wasting energy, he said.
The No. 1 energy expense on most farms is nitrogen fertilizer, Berns noted. Farmers spend billions on nitrogen, when there’s 77 percent in the atmosphere.
Why? As a stable molecule, nitrogen occurs as two atoms. In order to get nitrogen into a form that can be used, the molecule must be pulled apart; nitrogen must be combined with hydrogen or oxygen.
“During World War II, we learned how to break the N2 bond and make bombs. When the war was over, we had these big factories and they started making commercial fertilizer,” Bern said.
“In the natural system, God created tiny bacteria to do the same thing as those factories, but at a micro-scale. Those rhizobia grow on the roots of legume plants.”
Plants cannot make their own nitrogen, he said, but the bacteria can. But the rhizobia don’t do it for free. They cannot make their own food and are completely dependent on the plant for their “paycheck” — carbon in the form of a glucose molecule that comes from the plant.
This exchange also happens with other bacterial organisms, azospirillum and azotobacter, in association with grasses and other plants, although not as efficiently as rhizobia.
Soil has most of the minerals needed to grow a crop — resources such as macronutrients and micronutrients.
A soil test does not tell you what is there, but what is present in a form available to plants.
Plants by themselves can’t get the nutrients out of the soil, but the microbiota can. They excrete chemicals that dissolve the minerals, bring it back through their hyphae and provide it to plant roots in exchange for carbon.
Berns equated the efficiency of the U.S. interstate highway system and all the feeder roads to the mass of roots and mycorrhizal fungi beneath a healthy plant system.
A soil system without mycorrhizal fungi is like a country’s infrastructure without adequate roads, rail lines or ports — like the problems facing Brazil, he added.
Plants communicate their infrastructure needs by the different chemical compounds they exude, which can be carbohydrates, sugars, proteins, fats, lipids or oils. Each signals something different to soil biota. Plants also release volatile chemicals into the air, when under attack by insects, for example. They can call for defense from ladybugs or wasps.
His take-away points can be seen in the longer of several YouTube videos of his presentation entitled “Carbonomics.”
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