Dirt First

The March/April 2016 issue of the beautiful environmental magazine, Orion, features an article about “a revolution in the science of dirt,” which — it claims — “is transforming American agriculture.” The article is called “Dirt First” and is written by Kristin Ohlson. Like most good stories, this one has a hero, in this case Rick Haney, a USDA soil scientist.

“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 neighbor applied, and then maybe a little bit more, hoping for a jackpot combination of rain, sunshine, and a good market.

[…]

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.”

Read the full article here: “Dirt First

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