Diggin’ Dirt

healthy soil

Soil is the “excited skin” of the earth, as soil scientists put it, and whether we nourish that skin or scrape away at it has big implications for mitigating and weathering climate change.
~ Ula Chrobak

I have played and worked in the dirt and mud in many places. From ocean beach sand castles to curbside dams in the gutter, I’ve dug and filled holes and planted gardens and trees. I’ve drawn maps and faces in the dirt and thrown dirt clods at my brother and friends.

In Oklahoma, the soil was red and permanently stained your white T-shirts. In Arizona, the fine sand pervaded your house through cracks around the doors or windows and formed small dunes in your carpet. In Georgia, it was black and rich and anything planted grew like crazy — like Kudzu. Sometimes the soil is grainy or fine, sometimes it is hard, or sticky when wet. It can smell, well, earthy or be dry and acrid, making you sneeze.

But soil is more than just chunks of minerals — it’s full of organic matter, including all kinds of tiny living organisms. Ula Chrobak tells us, “As plants pull CO2 from the air and incorporate the carbon into their leaves, stems, and roots, they also add it into the ground. Left undisturbed, the ground beneath a forest or grassland serves as a bank of carbon.”

That carbon is critical to soil health. According to the Nature Conservancy, “the soil nurtures a complex web of microbes with the healthiest soils often being those with the greatest diversity and abundance of life. Healthy soil more efficiently stores and recycles carbon, water, and nutrients such as nitrogen and phosphorous.”

Carbon, that harbinger of climate change, is stored in the soil as well as in vegetation. Improving the soil’s capacity for carbon uptake and storage could be an important factor in reducing carbon dioxide in the atmosphere. Brian Barth notes, “The problem is that modern agricultural practices emit far more carbon than they sequester … But minor tweaks to production methods — including planting cover crops, employing no-till cultivation, and converting to rotational grazing — begin to reverse the flow of carbon from the sky back to the farm.”

Per the Nature Conservancy, “Reduced tillage decreases disturbance of the soil, thereby improving the soil’s ability to retain nutrients and sequester carbon dioxide from the atmosphere. Cover cropping between cash crop seasons is a heritage practice that maximizes the time each year that living roots are building soil nutrients and keeping the surface protected. Diverse crop rotations help build nutrients, limit erosion, and foster soil carbon sequestration.”

Dan Nosowitz reports on a study in the UK that finds cover crops also make the soil friendlier for earthworms. “Earthworms are a vital component of many healthy soils, digesting plant waste like corn husks and depositing their own waste as vibrant, fertile topsoil. A large earthworm population is a solid indicator of good soil health.”

Brian Barth also observes, “In the popular imagination, solutions to climate change are often boiled down to reducing fossil fuel use and investing in alternative energy. Some would add underground carbon storage schemes or geoengineering techniques to the list, and perhaps tack on conserving forests and planting trees, as everyone knows this is nature’s way of pulling carbon out of the atmosphere … just like the trees in a forest, crops interact with microbes in the soil to produce organic matter, a stable form of underground carbon storage that outlasts the growth and decay of aboveground vegetation … Farmland is — potentially — a vast, inexpensive way to sequester carbon and store it long-term. ”

Our farmers are challenged to feed a growing global population in the face of climate changes and weather uncertainty that can disrupt their production and markets. Relatively basic advances in agricultural techniques can be important tools in fighting climate change as well as keeping the Earth’s food production viable.

Additional information:
Brian Barth, Q&A: Is Agriculture the Answer to Climate Change?, August 26, 2019, Modern Farmer

Ula Chrobak, A Great Climate Comes from Happy Soil. Could Happy Soil Come from California?, August 15, 2019, Popular Science

Jack Kittredge, Soil Carbon Restoration: Can Biology do the Job?, August 14, 2015, Northeast Organic Farming Association/Massachusetts Chapter, Inc., http://www.nofamass.org

Jessica Kutz, Can Small-Scale Farmers Grow A Healthier California?, May 20, 2019 , High Country News

Dan Nosowitz, Cover Crops Can Triple the Amount of Earthworms in Soil, September 29, 2019, Modern Farmer

The Nature Conservancy, reThink Soil: A Roadmap for U.S. Soil Health, November 2016

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