Soil Health Regeneration, Remediation, and Preservation: As Above, So Below

There are 9,096 stars visible across both hemispheres of the sky. This is a tiny fraction of the stars out there; NASA's best estimates tell us that the Milky Way alone is made up of approximately 100 billion stars and that there are 2 trillion galaxies in the universe comprising approximately 200 billion trillion stars (got that?). But believe it or not, this abundance is paltry compared to the numbers of living organisms we can find beneath our feet. A single teaspoonful of soil can contain more than 10,000 species and over four billion microorganisms (each with an average of four million base pairs of DNA), as well as several miles of fungal filaments. Today our planet is populated by about a trillion individual species of microorganisms. The total number of bacteria on Earth is estimated to be five million trillion trillion, or 25,000 times the number of estimated stars in the universe. 

Soil Is Central to All Life on Earth

The soil microbiome is an astonishingly diverse, complex, and interdependent ecosystem that's home to more than half of the species on our planet. Among the trillion species living in the mineral deposits and humus we think of as dirt, there are microbes that cycle phosphorus and nitrogen into nutrients plants can use, and microbes that decompose organic matter as well as pollutants; there are mycorrhizal fungi that form symbiotic relationships to plants and enhance aeration and moisture, as well as ones that secrete acids to mine mineral's particles; and there are bacteria that inhibit pathogens and others that fix nitrates and ammonia. This expansive and complex ecosystem is essential to the existence of pretty much everything that we humans need to survive on Earth — what we eat, drink, and breathe. Ninety-five percent of humans’ per capita calorie consumption worldwide comes from crops that grow directly in the soil or from food sources that indirectly rely on it (versus about 2% from the world's oceans.) 

But There’s a Problem …

Which makes it a matter of concern that roughly 50% of the world's topsoil has been lost in the last 150 years. Deforestation, overgrazing, urbanization, compaction, pollution, lawns, and climate change have all played a part, but the majority of soil degradation and loss has been due to intense, mismanaged farming. Calories are cheaper and more widely available than ever, but they come at a cost: cosmetically perfect produce with half the micronutrients of their organically farmed cousins (and dozens of different chemical residues) travel an average 1,500 miles from industrial farm to plate. What’s more, industrial farming has resulted in the loss of  more than 50 billion metric tons since the late 19th century. Persistent tilling breaks apart fragile soil structure and fungal mycelial connections, leaving organic matter and microbes exposed to the elements and vulnerable to flooding and erosion. Heavy machinery compacts the soil, forcing out air, crushing roots, and preventing water absorption. Mono-crops drain the soil of nutrients and destroy biological diversity — and as these crops are consequently more susceptible to disease, pests, and pathogens, they require regular application of pesticides. To restore crop productivity, we apply more and more toxic agrochemical fertilizers, which further degrades the soil, as well as our water. At the current rate of soil degradation, 95% of the Earth's soil will be degraded by 2050. In celestial terms, it'd be the difference between Nantucket and Los Angeles in terms of what you could see in the night sky. This isn't just a case of a keystone species being lost: we're losing a keystone ecosystem that supports 80% of the species on earth. 

It's not just the soil that's increasingly degraded: soil and human microbiomes are interconnected, so soil health is human health, and both are at a tipping point that will determine our survival. The human gastrointestinal tract is host to trillions of microbiomes of microbial species that have co-evolved with us to form an intricate and mutually beneficial relationship. These foreign microorganisms are primarily introduced to us through our trip through the birth canal, through breast milk from our mothers, and through our diet, and they perform a range of physiological functions that provide nutrition and medicine. Soil, microbes, plants, and animals evolved together as an ecosystem, and contaminants in the soil accumulate in plant tissue and are passed on to the species that eat them. Much like microplastics, agrochemicals are easily dispersed throughout our environment and are now found in our atmosphere, rainfall, soils, plants and water, and throughout the human body. So what happens when we replace a biodiverse symbiotic diet that evolved over millions of years among trillions of species with one whose nutrients and pathogen resistance are derived from agrochemicals? For starters, there's an onslaught of human immunotoxicity. Cancers, birth defects, neurological and developmental toxicity, and endocrine disruptors have spiked, while human sperm counts globally have fallen by more than 50% in the last 50 years. 

There’s Still Time to Save the Soil

The good news is that it’s not too late to save the soil, and in a lot of meaningful ways we’re already starting to. Some of the best hopes for both soil and human health lie in returning to “the old ways” while taking into account new scientific understanding — practicing regenerative agriculture, horticulture, and permaculture. Whether you keep your ear to the ground or head in the sand, you've probably heard a lot about both restorative and regenerative agriculture, including from an excellent article, Raising Farmers on Nantucket, by Britt Bowker in the last issue of this magazine. There’s abundant information out there and around the world. Farmers are making tremendous strides toward regenerative agriculture, but consumer engagement is essential. When it comes to food, for yourself and those you feed, for those who grow it and the plants and animals that become it, for health and flavor, for the environment and the future, know what you eat: choose local and soil-grown organic.

In addition to making informed food decisions that prioritize sustainability, we have a wonderful opportunity to leave future generations a healthier Nantucket soil than we ourselves have enjoyed, and along with it a more resilient community. The thin layer of moraine and organic matter that accumulated since the Laurentide ice sheet retreated about 18,000 years ago has been severely degraded since European settlement and farming began in the 1600s. At some point during the last few hundred years, nearly all of the land on Nantucket (and in New England) has been cleared of forest and used for agriculture, leaving soil exposed to the elements. Peat harvesting for fuel, especially when the British blockaded the island during the War of 1812, further depleted Nantucket's natural nutrient stores. Rapid and widespread development of suburban residential housing in the last 50 years has left these already ravaged soils further compacted and degraded by construction and by non-native lawns and gardens. 

Regenerative Landscaping

We’re in the midst of a construction boom that poses an ongoing threat to Nantucket soil, but many landscape strategies exist to both preserve and restore soil on Nantucket. In addition to the roughly 10,000 dwellings already on Nantucket, anywhere between 2,000 and 25,000 additional dwellings may be built under current regulations. “If you are planning new construction or remodeling, one of the best things you can do is find out if you have great native vegetation on your site, and work with your designer and the people doing the construction to retain native plants and trees rather than clearing the full lot and then needing to replant — it helps retain soil integrity on some areas of your property as well as being a boost for the local ecosystem, and helps Nantucket retain more of its natural landscape appeal,” recommends Nantucket Conservation Foundation plant research ecologist/botanist Kelly Omand.

“The average newly constructed residential landscape has a lot that is typically over-cleared (so the whole lot turns into a parking lot), top soil that is trucked off the job site (the subgrade becomes extremely compact from trucks, equipment, foot traffic, etc.),” says organic landscaper John Schichtel. Once landscaping begins, John says, if you don’t address compaction, you miss the opportunity for a healthy ecosystem to exist; you’re also putting stress on any irrigation systems, since water can’t percolate in those conditions. Compacted soils also eliminate the chances of natural nutrient cycling; or microbes producing nitrogen, phosphorus, potassium naturally, and at a rate which plants will use, so people turn to fertilizers, he says. “Once you start feeding a plant with fertilizers, the plant will always rely on those fertilizers. It becomes a cycle of constant human interaction to support plant life. The ultimate goal of landscaping should be to put the natural ecosystem back the way it was prior to construction; not create a new ecosystem that we know nothing about and requires constant human interaction to support life.”

Regenerative landscaping aims to restore natural ecosystems and improve soil health through holistic maintenance strategies and sustainable, site-specific plantings. To avoid the nutrient, pesticide, and water input cycle, this gardening philosophy favors native plants with deep root systems that stabilize and nourish soils and embraces the entire life cycle of plants, including the nutritionally beneficial and often even beautiful stage of death and decay in the garden.  “Leaf litter” provides an incredible array of nutrients and minerals that enhance soil fertility, as well as organic matter that improves soil structure and provides shelter and habitat for insects and microorganisms. Hither Creek Gardener Julie Wood points out that naturalistic approaches require a transformed perspective on the aesthetics of what a healthy winter landscape looks like in order to reap the benefits: “My house was built by someone else in 2006. I have no idea what they did with the top soil during construction, but when we moved here in 2012 it was just a sand pit. I wanted a garden, and at the time, was just beginning to really dive into creating habitat in the garden. I used compost while planting but then let nature take over by intentionally leaving leaf litter in the beds and not doing any kind of fall clean up so that seed heads and stems were available over the fall through mid spring. The results of this passive approach are undeniable. Twelve years later, I have beautiful chunky soil, still sandy but with some bulky organic matter. The bird, butterfly, [and] insect activity has drastically increased, much to my delight. It feels dynamic to live amongst and [is] so entertaining to observe.”

It’s worth bearing in mind for both landscaping after construction as well as garden soil restorations that disturbing soils can lead to surprises. Kelly Omand observes that “Seeds stored in soil are one of its treasures — or its bane; they can be either native species that are brought to the surface and help regenerate right away after restorations or construction, or they can be invasive or weedy non-natives, depending on the site’s history.” 

What About Invasives? 

What if the invasive plants are worse than the pesticides? “There are some cases when using pesticides is the necessary alternative,” explains Seth Engelbourg, Naturalist Educator and Program Manager at the Linda Loring Nature Foundation. Some plants do not respond well to mechanical removal, he says, such as Japanese knotweed. Due to its extensive rhizome system, it can be hard to dig deep enough to remove the whole structure, and excavating that much dirt and plant material can also accelerate erosion. And because knotweed spreads via fragmentation, mechanical methods such as mowing may spread plant pieces over a wider area and worsen the infestation. “Using an herbicide to kill the plant in place is ecologically preferred in this case,” Seth says, but stresses that pesticides should always be applied by a licensed applicator, should be used in accordance with the product label and any applicable laws, and that areas treated with pesticides should be monitored before and after to check for potential impacts. 

We are extremely fortunate that over half of Nantucket is conservation land and that each of us can make efforts to improve the health of our native ecosystems, whether that be by composting our kitchen waste or restoring a compacted landscape. It can take hundreds or thousands of years to form an inch of topsoil naturally, but many restoration projects require minimal input and only 6 to 10 years to regenerate healthy, sustainable ecosystems. Successful landscape soil restoration strategies often include loosening compacted soils, reintroducing nutrients and microbial components, and finally reintroducing native plants to protect the soil. Upon successful completion, landscape soil restorations can be a lot less taxing than agricultural ones that constantly remove nutrients (food) from the ecosystem, and once the soil and vegetative communities are restored, they can be self-sufficient and self-sustainable if largely left alone. 

Prepare the Soil

John Schictel grew up in the family nursery business and knows his plants, but it's especially refreshing and inspiring to hear him speak about the symbiotic relationships within the soil microbiome and his focus on building healthy soils for healthy plants. John’s holistic approach is informed by biology versus chemistry, by the philosophy that “we do not inherit the Earth from our ancestors, we borrow it from our children,” and by a humble reverence toward nature. 

Plenty of landscaping business models rely on regular application of mulches and fertilizers, but John’s goes a step further with its goal of establishing naturally occurring sustainable conditions. He knows that healthy soil is every bit as important as choosing the right community of plants. He invests heavily in preparing the soil, and while this entails additional upfront costs, it results in much healthier, pathogen-resistant plant communities that ultimately don't require the endless annual nutrient inputs of a conventional garden. In the end, it is far more cost effective to treat the soil up front rather than year after year, especially when one considers the risks poor soils pose to expensive plantings. It's the landscaping equivalent of “Give someone a fish and you feed them for a day; teach them to fish and they feed themselves for a lifetime”.

“The financial side of the industry goes back to ‘it’s a process not a product,’” Schichtel says. “In the process of examining how microbial life works in your soil, and gaining an understanding of the landscape, you create a self-sustaining landscape — one that does not require tons of human interaction. A landscape that can handle heavy rains or extreme drought. A landscape that requires little to no irrigation. A landscape that does not require substantial chemical inputs annually.” 

Remediation Can Work

The work of landscapers like John demonstrates that remediation efforts can lead to sustainable ecosystems that will persevere in perpetuity without further intervention. One such effort — the Nantucket Conservation Foundation's largest restoration to date — is currently taking place at the Windswept Bog (see story, page 54), where workers are transforming nearly 40 acres of natural peat, agricultural soils, and artificially deposited sand (used on cranberry bogs to stimulate growth and bury insect pests) into wetlands, prairies, and sandplain grasslands. They’re filling irrigation ditches and removing berms to allow for a slow, meandering natural wetland flow through the landscape to help soils and plants filter out nutrients that would otherwise end up flowing into our harbor. 

The Soil Beneath Our Feet Might Hold Answers

History is full of tales of alchemists searching for the elixir of life, metallurgical transmutations that turn lead into gold, and divine reflections of heaven on Earth; perhaps their elusive Philosopher's Stone is healthy soil. Thanks to modern science and technology, we're beginning to understand more about the fundamental principles that allow for fungi to release minerals from rocks, microbes to transform dead organisms into life, and the connections between the soil microbiome, the trillions of microbes living within us, and human health. 

But there is still much to learn, and soil science itself is in the midst of a paradigm shift. To produce enough food for a growing population on dwindling soils, agricultural research has expanded considerably to include such topics as electron microscopy, spectroscopy, and other cutting edge analytical tools; GIS, satellite and drone-based soil analysis and mapping; and various sensors to monitor soil microbial health, pH, nutrients, compaction, and moisture. And soil study is becoming fundamental to health care research: Chemists and medicine researchers are now using artificial intelligence to quickly identify and sequence molecules produced by soil bacteria that could become antibiotic medicines. Likewise, scientists are looking to the earth for solutions to climate change and environmental hazards: Researchers have identified a number of microbial soil bacteria and fungi that can break apart and digest persistent toxins, such as PFAS, and many climate change scientists and policy makers are hopeful that excess carbon dioxide may be removed from the atmosphere and sequestered in soil.

Saving soil will take both scientific advances and individual conservation efforts. Education is imperative to understanding the challenges, alternatives, and various solutions, as well as developing innovative solutions (Windswept Bog) to ongoing and future problems (dustbowl disasters). But so too are public policy and individual engagement. We have the technology and know-how to restore damaged soils, as well as the foresight to save those that remain healthy, and we need to be armed with knowledge of the consequences should we fail. While mitigating many challenges of climate change seems increasingly unlikely, saving soil is well within our reach and something each and every one of us can contribute to.

What Can You Do?

• First and ideally: do no harm. Fight to preserve those natural ecosystems that remain, minimize the disturbance for areas that are being developed and restore those that have been damaged or degraded. 

• Eat local and soil-grown produce ideally grown with organic practices. Support methods of regenerative agriculture that restore soil and ecosystem health, address inequity, and protect our land, waters and climate.

• Use organic products (textiles, beauty products, cleaning products). It’s not just about our food: cotton uses an estimated 6% of the world's pesticides and 10-16% of the insecticides, but only accounts for 2.4% of the world’s cultivated lands. 

• Get rid of your lawn and grow native plants. 

• Talk with your local farmer, landscaper, or university about soil health. 

• Compost. Reduce, reuse and recycle.

• Invest in sustainable, green ventures and organizations. 

• Help those less fortunate than you — climate change disproportionately impacts the poor. 

• Spread the word…share this article. 

At Home

Most soil microorganisms need the same things we do to thrive: food, water and oxygen. Home gardeners can help encourage beneficial microorganisms to improve their soil fertility and structure in several ways:

• Avoid pesticides
• Add compost
• Avoid disturbances (tilling, driving)
• Provide vegetative protection from the sun, wind, salt spray and rain

Some More Local Resources

Toscana Corporation has been Nantucket owned and operated since 1979; in addition to demolition and home-moving services, Toscana sells a Nantucket Soil Collection — a range of soils and compost produced 100% on Nantucket island. Their organic, kid- and pet- safe soils and compost are made with recycled, non-woody yard waste from local landscapers and homeowners. toscanacorp.com/shop