Biodiversity in soils

Biodiversity is a key word in the following article which is from a USA based website called Dirt First – Food and Environment Reporting Network. The thoughts gel with the principles Vince Heffernan is referring to and with that which the EAAA supports. In this article soil ecologist Rick Haney PhD tells the story about soil biology and his invention to measure the activity in soil. The EAAA will attempt to get a response from a soil lab in Australia on the Haney method as described in this article. The article is by Kristin Ohlso:

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Rick Haney (Image source: https://thefern.org/2016/04/dirt-first/)

“Our entire agriculture industry is based on chemical inputs, but soil is not a chemistry set,” Haney explains. “It’s a biological system. We’ve treated it like a chemistry set because the chemistry is easier to measure than the soil biology.”

In nature, of course, plants grow like mad without added synthetic fertilizer, thanks to a multimillion-year-old partnership with soil microorganisms. Plants pull carbon dioxide from the atmosphere through photosynthesis and create a carbon syrup. About 60 percent of this fuels the plant’s growth, with the remaining exuded through the roots to soil microorganisms, which trade mineral nutrients they’ve liberated from rocks, sand, silt, and clay—in other words, fertilizer—for their share of the carbon bounty. Haney insists that ag scientists are remiss if they don’t pay more attention to this natural partnership.

“I’ve had scientific colleagues tell me they raised 300 bushels of corn [per acre] with an application of fertilizer, and I ask how the control plots, the ones without the fertilizer, did,” Haney says. “They tell me 220 bushels of corn. How is that not the story? How is raising 220 bushels of corn without fertilizer not the story?” If the natural processes at work in even the tired soil of a test plot can produce 220 bushels of corn, he argues, the yields of farmers consciously building soil health can be much higher.

Less than 50 percent of the synthetic fertilizer that farmers apply to most crops is actually used by plants, with much of the rest running off into drainage ditches and streams and, later, concentrating with disastrous effects in lakes and oceans. Witness the oxygen-free dead zone in the Gulf of Mexico or tap water tainted by neurotoxin-producing algae in Ohio: both phenomena are tied to fertilizer runoff. Farmers often apply fertilizer based on advice from manufacturers and university extension agents who are faithful to the agrochemical mindset, using formulas that tie X amount of desired yield to Y pounds of fertilizer applied per acre. Or they apply fertilizer based on a standard test that gauges the amount of inorganic nitrogen, potassium, and phosphorus—the basic ingredients of chemical fertilizers, often referred to as NPK—in a soil sample. Or they apply what they put on the year before, or what their neighbour applied, and then maybe a little bit more, hoping for a jackpot combination of rain, sunshine, and a good market.

“Farmers are risk averse,” Haney says. “They’ve borrowed a half million dollars for a crop that could die tomorrow. The last thing they want to worry about is whether they put on enough fertilizer. They always put on too much, just to be safe.”

The standard soil test, developed some sixty years ago, focuses only on the chemical properties of soil. Haney began developing his test in the early 1990s to focus instead on the soil’s biology. Based on the vigor of the microscopic community in a farmer’s soil, his recommendations usually call for far less than what the farmer hears elsewhere. The yields of those who heed his advice often remain the same, or rise.

A SINGLE TEASPOON of healthy soil holds billions of soil microorganisms, including bacteria, fungi, and other tiny life forms. These organisms crowd around the roots of plants, jostling and competing for carbon exudates that plants dole out according to their needs. Sometimes the plant trades a squirt for a mineral nutrient like zinc or potassium. Sometimes the plant offers treats in exchange for help defending against a pest or disease. The plants aren’t just responding to the various microscopic bidders, either: they can change the formula of their exudates and send chemical messages—kind of like lighting a flare—to attract specific players with specific services. For instance, scientists have discovered that when corn rootworm larvae attack some older varieties of corn (not the modern varieties bred for high yield), the plant sends out a chemical signal to beckon a nematode that feasts on this pest. “They’re sending out an SOS to this very specific organism,” says Ray Weil, an ecologist at the University of Maryland and an author of the classic textbook The Nature and Property of Soils. “‘Dinner is here—come and help yourself!’”

When we admire good soil’s dark chocolate-cake sponginess and sweet smell, we’re admiring the handiwork of trillions of soil microorganisms over time. They eat carbon and expire carbon dioxide, just as we do, but they also “fix” a percentage of that carbon in the soil. Barring disturbance, it stays there for a very long time. Some is used to make a carbon-based glue with which the microorganisms engineer soil into tiny clusters to protect themselves and control the flow of air and water in their habitat. Thus, good soil is more like a coral reef than a rock, with about 50 percent of its volume comprising these open pockets.

Photosynthesis is the only process that safely and inexpensively removes carbon dioxide from the atmosphere, allowing carbon that is a problem in the skies to become a boon for the land. Based on this principle, one hundred governments and nonprofits launched the 4/1000 Initiative at the recent Paris climate talks, calling for an increase of carbon in the world’s soils by 0.4 percent per year. This relatively small boost will not only radically improve soil fertility but also, the coalition claims, halt the annual rise of atmospheric carbon dioxide.

AS A HIGH SCHOOL STUDENT in Oklahoma, Rick Haney worked for wheat and cattle farmers and dreamed about getting into farming himself. But then, as now, land was expensive, so he shelved that particular fantasy. When he graduated, his classmates voted him most likely to be either dead or in a rock band in ten years. Instead, he drifted in and out of science classes at Southwestern Oklahoma State University.

Over the years, Haney continued to work alongside his farmer friends, sometimes pulling fifteen-hour days. “I watched these guys take out big loans and struggle every year,” Haney says. “Every time their plants or animals died, it was money down a black hole. My uncle encouraged me to get an advanced degree to help guys like that.”

Studying at Texas A&M for a masters and then a PhD—which he wouldn’t receive until he was forty-two years old—Haney began questioning the wisdom of the standard soil test, in use since the mid-1900s, when synthetic fertilizers were embraced by farmers who saw them as a quick path to productivity. The standard test determines how much nitrogen, potassium, and phosphorus a soil sample contains. But that made no sense to Haney. “It’s not about single molecules,” he says. “Soil health is all about complex systems.”

The test Haney ultimately developed begins with drying a soil sample to suspend the microorganisms’ activity. When the sample is rewetted, the microorganisms roar back into business, exhaling a burst of carbon dioxide. Haney measures that burst, which demonstrates the health of the farmer’s resident microbiotic community—its vigor is the most important indicator of soil fertility. Then he uses more water and weak acids, akin to those in plant exudates, to extract the nitrogen in the sample. The standard soil test measures only inorganic nitrogen, the kind that’s found in chemical fertilizers and that plants can use immediately. It ignores organic nitrogen, which that hard-working community of microorganisms can transform into a plant-available form. The Haney Test is more time consuming and costly than the standard test, but it reveals to farmers how much total nitrogen is already in the soil and helps them slash expensive chemical fertilizers.

Original post: https://thefern.org/2016/04/dirt-first/

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