Warning: Recent studies may challenge deeply held assumptions about pesticides and the environment.
Most agronomists understand farm pesticide use is perhaps the single greatest factor in protecting wildlife, saving habitat and keeping our waters clean. Recent scholarship should help the truth of that assertion reach the public.
Pesticides empower us to grow much more per acre than we did 40 years ago. Stanford University researchers found that, without modern farming, cultivated farmland would likely need to double to produce the same amount of food.
Modern farming, including pesticide use, has saved a land mass greater than Russia from falling under the plow. Mechanization, fertilizers, plant breeding and biotechnology also play key roles in modern farming. But studies show environmental gains directly attributable to pesticides.
In a new study, agronomist Mike Owen of Iowa State University says pesticides help U.S. farmers produce four times the corn and wheat of the early 1900s without clearing forest habitats or draining wetlands.
Because herbicides control weeds without plowing, the University of Wisconsin’s Paul Mitchell reports in a companion paper that farmers save more than 550 million gallons of fuel per year, equaling more than 2 billion pounds of carbon-dioxide emissions. Greenhouse gasses are not released into the atmosphere.
The key is “no-till,” or “conservation till,” farming. Residue from prior crops is left on the field, acting as natural mulch, holding soil and moisture, and deterring weed growth. Farmers simply seed and spray.
Plowing promotes decomposition of organic matter that is needed to hold water and critical nutrients, enhance soil productivity and support biodiversity. It leaves soil loosened, upturned and prone to erosion, ultimately polluting the air and water. With no-till, run-off drops, soil is saved. Surface water is cleaner. No-till depends on controlling weeds without the plow, once again demonstrating the importance of herbicides.
Mitchell says some 88 million acres, or almost 36 percent of U.S. cropland devoted to major crops, use one of numerous no-till systems. One family of herbicides, triazines, was instrumental in this revolution. One of those — atrazine — gave corn farmers the confidence to adopt no-till methods.
In 2010, I joined Owen and Mitchell, and Richard Fawcett, a retired Iowa State University professor, to quantify the benefits of triazine herbicides. No-till, made possible by atrazine and other triazines, reduced erosion by more than 40 percent in the last 30 years. That saves some 55 million to 85 million tons of soil a year.
The study’s findings are applicable to Georgia farmers. Atrazine and other pesticides add more than $2.4 billion of crop production in Georgia. They control weeds and help the environment. Atrazine is vitally important to our economic health.
Mitchell estimates the saved soil’s value between $210 million and $350 million per year. The greenhouse gasses not emitted — because farmers are not plowing — tally as much as 280,000 metric tons per year.
One might think environmentalists would celebrate. No.
For instance, American Public Media’s “Marketplace” program recently began a series of reports on agriculture. It interviewed a Mexican farmer who practices no-till, and noted it is widespread in the U.S. Not once did the word “pesticides” come up, let alone any pesticides that make no-till possible.
Perhaps “Marketplace” chose not to challenge its audience with all the facts. That’s not surprising, since its audience — and all of us — are barraged by negative stories on pesticides usually by activists who oppose modern farming itself.
David C. Bridges is president of Abraham Baldwin Agricultural College in Tifton.
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