Lessons of the Lamp Post Garden: How a Healthy Soil Microbiome Can Slow Climate Change, Fix Agriculture & Make Just About Everything Better
Started from seed, the three plants are now five feet tall and at least eight feet across combined. They dance and sway to the flutter of wings as butterflies, bees, hummingbirds and moths take turns flitting and buzzing among their dozens of blooms. Giant zinnias have been dwarfed and purple asters nearly hidden. Only a moonflower vine that has spent the summer spiraling its way to the top of a lamp post has a shot at growing taller.
It is an unlikely Eden born of a doomed attempt to make the lawn look neat and tidy. The man who cuts the grass would dig a circle around the lamp post each spring and each year it grew a little wider. Finally, I fenced it in and called it a garden: The Lamp Post Garden. The first flowers were transplanted perennials, each the dominant plant in its home bed, now left to duke it out: day lily versus hosta verses sedum! Next, spring bulbs were tossed into the mix: tulips, tiny lilies and, of course, every theme and variation of rabbit-defying daffodil. Then came some plant-sale freebies: asters, penstemons, echinacea, black eyed susans and a few still yet to be identified. A constant battle rages at the fence-line between grass that wants in (oh to grow tall and proud and produce seeds!) and ground cover flowers determined to break out. By mid-summer, a handful of scatter-planted zinnia and “butterfly mix” annuals sprout along the edges.
If there is a unifying theme, it is the random kismet of constant change. From earliest spring, the garden astounds a steady stream of little kids with eye-level bursts of color as they roll by in strollers. Almost every day, there is something new to see. By fall, the Lamp Post Garden astounds pretty much everybody. I gave up trying to count the number of different species thriving within its circle. There are a lot and I love them all.
It turns out there is even more to love below ground. My lackadaisical gardening style has unwittingly nurtured a wildly healthy soil microbiome. For the most part, the plants need very little help from me, requiring only occasional watering and a tiny bit of weeding, mostly to keep the day lily’s latest surreptitious attempts at territorial expansion in check. My invisible helpers beneath the surface—soil bacteria, fungi, bugs, worms, itty bitty mollusks (snails) and other microfauna—do most of the work.
BETWEEN A ROCK AND A BLOOM: THE SOIL MICROBIOME
In farming circles, my minimalist gardening technique would fall under the umbrella of what is called conservation or regenerative agriculture. There are three requirements:
- No-till: Ditch the plow in favor of drilling small holes for individual seeds.
- Plant a variety of ground cover crops to stabilize soil, tamp down weeds, fix soil nitrogen (legumes) and provide “green manure.”
- Plant crops in complex rotations to thwart insect pests and pathogens and also to help build soil.
By working in sync with nature to cultivate the soil microbiome, it is possible—at scale—to dramatically reduce pricey fossil fuel inputs: diesel, pesticides, herbicides and fungicides. Those savings drop straight to the bottom line. As costs go down, soil fertility goes up, but that is just the beginning of an extraordinarily virtuous circle.
- A thriving soil microbiome means more micronutrients are accessible (bio-available) to plants, which makes them more nutritious for whomever or whatever eats them or sips their nectar.
- Soil organic matter (SOM—compost and mulch—the salad upon which microbes dine) improves soil absorbency. It is also laced with beneficial fungal mycelia that effectively extend plant root systems. The mycelia also produce glomalin, a sticky substance that literally holds the soil together. Not only are SOM-rich farm fields better able to handle extreme rain events, but also drought. More water stays in the ground, reducing run-off and erosion. Run-off from conventional farms, which is full of chemical fertilizers, has been linked to the development of massive aquatic “dead zones” from the Gulf of Mexico to Lake Erie. No run-off, no dead zones.
- The combination of cover crops and no-till can prevent massive dust storms that have become a significant problem from the Dakotas to China. Since the ground is always covered, there is nothing to blow away. Farm dust, poisoned with pesticides and other chemicals and the air-borne equivalent of run-off, presents a massive public health issue.
- Healthy soil can better handle extreme temperatures, so crops are less vulnerable to heat waves.
- The soil microbiome also plays a role in climate stability. Carbon can be stored in the air, water or ground and it is the balance between the three that keeps the planet on an even climate keel. A build-up in atmospheric carbon triggers global warming. Too much carbon in water leads to acidification with ecosystem-wide implications. In the soil, carbon is a proxy for fertility. Massive amounts of carbon that had been buried deep in the ground for millions of years has been shifted into the atmosphere and the oceans through the accelerated burning of fossil fuels over the last few centuries. This, combined with deforestation and conventional agriculture (which also transfer carbon from the ground into the air), has thrown the system out of whack. Restoring balance requires dramatically cutting emissions, while also putting carbon back in the ground at scale. Conservation agriculture is the best, fastest and cheapest way to accomplish the latter.
CHEMISTRY, BIOLOGY & GOOD INTENTIONS GONE BAD
With all the pluses, why is conservation agriculture still on the fringes? The basics of soil chemistry have long been known (the essentials of nitrogen, potassium, phosphorous and pH), but a solid understanding of soil biology has lagged behind. The mechanisms are subtle, dynamic and systemic.
Viewed simply in terms of chemistry, agriculture is a relatively straightforward matter of inputs and yields. Soil can be analyzed for mineral content and any deficiencies addressed. By contrast, soil biology starts with organic matter that benefits microbes rather than plants. In fact, for quite a long time the tiny percentage of soil that teems with microbial life was largely discounted as non-essential.
Shockingly, about a third of agricultural land worldwide is now considered degraded. The Green Revolution's promise to “feed the world” turned out to come at a very steep price. Bumper crops made possible by the chemical equivalent of steroids masked staggering devastation beneath the surface.
The soil microbiome is a thin, almost magical line between the inorganic and the organic in a system that stretches from the sun to the earth’s rocky depths. Between 30 and 40 percent of the energy that a plant generates through photosynthesis goes toward producing polysaccharides, carbohydrates and other goodies collectively known as exudates. These are delivered via roots as a kind of microbe bait. In turn, the microbes (which include fungi) provide essential minerals that they collectively helped extract from rock, along with a banquet of micronutrients and hormones that help a plant grow.
The microbiome is also part of a vast underground food chain that includes worms and bugs whose burrowing aerates the soil and whose micro-manure fertilizes it. When a plant loses leaves or dies, it becomes part the soil organic matter and the cycle continues.
(Aside: Some plants—including tomatoes—have developed the ability to kill bugs that crawl on them in order to add their bodies to the soil mix for nutrients. In short, carnivorous vegetables.)
Adding fertilizer isn’t itself a bad practice. Many no-till systems are set up to drill a second hole for nitrogen a few inches away from the seed. It is when the chemical load overwhelms the natural system that the virtuous circle flips into a vicious one.
- Plants pumped up with fertilizers don’t need to coax minerals from microbes, so spend less energy making exudates. The soil microbiome begins to die off which, in turn, means fewer micronutrients and growth hormones for plants.
- A diminished mycelial network means plant roots aren’t able to take in as much water. Also, the loss of mycelial glomalin leads to less absorbent soil, which increases the need for irrigation.
- The soil microbiome helps protect plants from pathogens, much as our gut microbiome helps keep us healthy. Its loss means crops are more vulnerable to disease, increasing the need for pesticides and fungicides, which further stresses the microbiome.
- Commodity crops with a simple two-step rotation (e.g, first corn, then soy, then corn, then soy) provide such a reliable target for insects and pathogens that the only way to control them is to spray. As the pests inevitably develop resistance, it leads to a chemical arms race and more stress on soil ecosystems.
- Herbicides trigger another arms race: superweeds versus ever-stronger herbicides, some of which can cause some truly disturbing collateral damage.
The bottom line: Potemkin crops may look great, but stand on atrophied roots in dusty dirt. They are also less nutritious and cost farmers a fortune in chemical inputs to grow.
They cost us a fortune, too. The USDA’s crop insurance policy, which incentivizes chemically-dependent commodity farming with minimal crop rotation, is heavily subsidized by taxpayers. According to a recent report by Iowa State University economist Bruce A. Babcock, “…taxpayers pay about 60 percent of the premiums, all the costs of administering the program and a large share of the claims payouts.”
Yet organic agriculture isn’t always the best answer either, notes David R. Montgomery, a MacArthur award-winning geologist whose meticulously researched new book, Growing a Revolution: Bringing Our Soil Back to Life, dives deep into the various ways conservation agriculture is practiced around the world. Organic farmers who plow are still doing damage to the soil microbiome—and to the climate as well. “By 1980, roughly a third of the carbon humanity had already added to the atmosphere since the Industrial Revolution came from plowing up the world’s soils, primarily in the Great Plains, Eastern Europe and China,” he writes. The best way to keep carbon in the ground is to leave the ground alone.
Montgomery instead calls for “organic-ish” farming where chemical inputs and soil disturbances are minimized, variety in cover crops is celebrated and crop rotations have enough complexity to keep bug populations in check.
THE TREADMILL TO OBLIVION & HOW TO GET OFF IT (*a hat tip to Fred Allen)
Montgomery paints a daunting picture:
- Annually, at least a third of all crops worldwide are lost to disease and insect pests. Even more is lost as waste after harvest.
- Soil degradation accounts for almost a half percent of global crop production loss each year.
- A single degree rise in global temperature could cut harvests of major grain crops by as much as 10 percent.
- It takes 10 calories of fossil fuel to grow a single edible calorie.
- There is generally less than a year’s supply of food globally.
As bleak and dire as that all may be, there is still hope. Switching to conservation agriculture can restore soil fertility remarkably quickly: in a matter of years, not decades and not, as generally thought, centuries. As long as all three pillars are in place—no-till, cover crops and serial crop rotation—the biology takes over.
Montgomery details example after example of land coming back to life and health, from commodity farms in the Dakotas to a farm run by a largely self-taught no-till evangelist in Ohio, and from the famous Rodale Institute in Pennsylvania to smallholder farms in Africa and Central America. Some farmers add livestock to the mix, carefully choreographing grazing patterns to maximize the cow-pie compost dividend. Some brew microbial teas to kickstart the soil’s natural microbiome. Some use biochar, an unusually stable form of carbon, to serve as a microbial matrix and also increase soil absorbency.
Conservation agriculture works in the mountains. It works in the tropics. It works in the Great Plains. It just works. Notes Montgomery:
“Unlike most production processes, farming has an inverse economy of scale in terms of total output. The common misconception that big, mechanized farms produce more food is based on yields per hectare for individual crops. Farms that grow a diversity of crops produce more food per hectare overall.”
When the great prairies of the American Midwest were plowed under to make way for fields of grain, farmers marveled at the soil’s fertility. That quickly dwindled, though, as year after year the plow laid siege to a microbiome and mycelial matrix no one knew was there. Soil carbon levels—a proxy of soil fertility—went from a robust five or even six percent down to two percent or less. Then chemical fertilizers (manufactured using a notably energy-intensive process) artificially boosted yields. On the surface, everything looked great. Now we know better.
It takes at least three years to to restore a degraded field to health using these techniques. That’s three years where yields are going to be lower than those of conventional farms—although in drought years, even recovering fields can outperform their worn out, chemically-sterilized counterparts.
The stark economic reality is that after figuring in costs for fuel, fertilizers, farm chemicals and proprietary GM (genetically modified) seed, many American farmers are lucky to squeeze out even a modest profit for all their effort. Yet the decision to step off the treadmill and make the change is a difficult one. In a sense, for many of these farmers crop insurance has become their crop, paying out substantially more than their taxpayer-subsidized premiums cost them. Still, some farmers are making the change and with stunning results.
With conservation agriculture, soil carbon levels can increase by as much as a half percent a year. Stéphane Le Foll, France’s former minister of Agriculture, calculated that a 0.4% increase globally would be enough to sequester 2.8 billion metric tons of carbon each and every year. Factor in fossil fuel savings from the reduced need for diesel, fertilizers and other petro-chemicals and the tally could be a third of global emissions. Some consider that to be a low-ball estimate.
To help farmers all over the world make the transition, a $300 million Land Degradation Neutrality Fund (LDN Fund) was launched at a UN conference on combatting global desertification this past September. It is the first such fund to tap private capital to address UN Sustainable Development Goals and will help chart a path for other social impact investors and philanthropies interested in supporting sustainable land use.
BACK TO THE GARDEN…
Conservation agriculture works because it embodies all the “best answer” qualities: modular, adaptable, flexible and scalable. It can work anywhere and everywhere. It turns out life isn’t about the survival of the fittest, but rather the survival of the fittest together: systems nested within systems. The microbially meek don’t inherit the earth. They run the show. Tamper with that at your peril.
One need look no further than the Lamp Post Garden to see the promise of a better future. From a butterfly perched atop a flower sipping nectar, to the microbes and mycelial hyphae sipping exudates on roots down below, it is all of a piece.