University of Washington geomorphology professor David R. Montgomery offers three steps to rebuilding our damaged soil in his book. He will speak at Town Hall Seattle on Tuesday, May 9.
“Growing a Revolution — Bringing Our Soil Back to Life”
by David R. Montgomery
W.W. Norton & Company, 316 pages, $26.95
“Are you ready for an optimistic book about the environment?” asks University of Washington geomorphology professor David R. Montgomery at the beginning of his fifth book. Also author of “Dirt: The Erosion of Civilizations,” he claims that although soil degradation is “the least recognized of the pressing crises humanity faces, it is also one of the most solvable.”
Put simply, a few crucial changes in agricultural practices — whether in kitchen gardens, small farms or huge agribusinesses — would rebuild our damaged soil. Montgomery’s good news is that three steps combining ancient insights and modern science are fairly easy and produce rapid results.
First — and this shift is major — we should stop plowing, which strips topsoil, releases carbon, increases moisture loss and raises soil temperature while killing organisms “from the common earthworm to specialized bacteria, mycorrhizal fungi and other microorganisms.” Instead, we’d use no-till planting, that is, minimally disturb the soil. In a Seattle P-Patch, this means digging rows of small holes, while in Walla Walla’s vast wheat fields, special equipment would cut narrow slots, drop seed and, at the same time, precisely apply a little fertilizer.
David R. Montgomery
The author of “Growing a Revolution — Bringing Our Soil Back to Life” will speak at 7:30 p.m. Tuesday, May 9, at Town Hall,
1119 Eighth Ave., Seattle; $5 (townhallseattle.org).
Too, if heavy machinery ran only once over a field, fuel and input costs, human work hours and air pollution would decrease; the resulting less-compacted soil would retain water, preventing conventionally widespread fertilizers and pesticides from running off, polluting waterways.
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Second, we should grow cover crops and keep the residue so that soil is always covered. Sometimes called “green manure,” cover crops would be planted after harvesting primary crops, then mowed or killed before the next season, helping suppress weeds and erosion while returning nutrients to the soil as they decay. Common choices include grasses and legumes such as hairy vetch and clover.
In small areas, we can kill or cut cover crops with hand tools and mowers; commercial farms can use heavy roller crimpers to kill or crush the cover crop. If installed on the front of a no-till planter, “a farmer can, in a single pass, plant seeds directly into fresh mulch and achieve effective weed control.”
The third step — all three are mandatory for successful restoration agriculture — is to rotate crops. Insects attracted to one crop would be less able to establish themselves, decreasing the need for pesticides or chemically treated seeds. It’s important to remember poisons kill both bad and good bugs — for example, predatory beetles that eat slugs. Also, pesticides and herbicides harm pollinators, birds and other nontargeted organisms.
To demonstrate experiences with these three steps, Montgomery traveled to big farms and small, organic and conventional, in North and South Dakota, Ghana, Pennsylvania, Costa Rica, Ohio and elsewhere. In case after case, he describes dark, rich soils resistant to drought, heat, weeds and pests. Many farms conduct experiments to study biodiversity, adding livestock, biochar (charcoal as a soil amendment), micronutrients, drip irrigation, sequestering carbon and even fertilizers such as “humanure,” a biosolid/sawdust/sand mix made in Tacoma.
However, Montgomery notes, change is slow. Big business, universities and government agencies aren’t racing to research and promote practices that cut profits. It’s still a grass-roots revolution. That the people who make the most money from agriculture aren’t the farmers, he observes, highlights the timeliness for change.