Rapid Topsoil Formation
The background of all of our work is healthy soil. And rapid topsoil formation has never been more urgent than it is today. Most of our projects and a large proportion of the work undertaken at the WSD Research Farm have a soil formation component built into the project. These range from terraforming systems to plant species and guild selections to work with mycelium and living mulches to subsoil plowing and keyline agriculture.
Rapid Topsoil Formation: Rotational Grazing
Rapid Topsoil Formation: Keyline Plowing
Inheriting Subsoil, Leaving Loam
By Ben Falk
"The nation that destroys its soil destroys itself." - Franklin D. Roosevelt, 1937
The State of Vermont soil maps say that I live on land composed of 6 to 12 inches of silty loam underlain by gravelly clay subsoil – not prime farmland but pretty great stuff for growing fruit and nut trees and agreeable to raising vegetables with proper fertility management. Yet, for the past five years I’ve been gardening and planting trees across this site and have found only pockets of silty loam soil a few times; it’s just clay, boulders, and more clay.
Where’s all the topsoil? Are the maps wrong?
Local elders in their 80s who have tended farm animals on this hillside have helped me to complete a picture that should not be surprising, for it’s the story of 75 percent of Vermont’s landscape: land clearing for timber extraction during colonial times, then potash production with the remnant forest combined with the sheep craze (2 million-plus sheep in Vermont). Add to this a ravenous diet of 10-30 cords of wood per house for heat, followed by hardscrabble grazing in the early half of the 20th century to polish off the rest of any remaining topsoil. Overgrazing sparsely vegetated, sloping land yields predictable results: massive transport of topsoil from the hillsides into Vermont’s great storm water detention basin – Lake Champlain.
Vermont’s soil story is similar to the rest of the country, with the Gulf of Mexico catching the topsoil washing off the exposed heartland of America at a rate of about 1 billion dump-truck loads per year. Only a comet or large asteroid collision with Earth has ever destroyed so much biological capital so quickly, and it’s likely that only one other potential event qualifies to be on this short list of globally catastrophic happenings: large-scale nuclear conflict.
The Great Soil Erosion of the 19th and 20th centuries represents the most massive transport of material on Earth since the last ice age. My small 10 acres on which, say, about eight inches of silt was lost amounts to roughly 12,000 tons of topsoil, or about 350 dump-truck loads. Standing at the sunset of the cheap-energy era, we now have to build a renewable society starting with about 200 million less dump-truck loads of soil than the first European settlers to this region had.¹ Strangely, for the past 50-80 years few have noticed the missing topsoil – except organic farmers and scuba divers in Lake Champlain, who have reported depositional zones of soil 10 to 30 feet deep across wide areas of the lake bottom.
Amazingly, most farming seems to go on as usual. We’ve managed to keep a small group of crops producing by trucking our fertility in from afar. As we begin to transition out of the cheap-energy era the reality of Earth’s missing topsoil will be felt more deeply than we might imagine. Healthy soil is, of course, the foundation of any agriculture and culture; food can only be extracted from land via fossil fuel fertilizers and pesticides temporarily, at best. Societies have long existed without highways and electrical grids; it’s when the soil and water give out – or the climate shifts quickly – that civilizations collapse. This collapse may continue to be delayed for as long as fossil fuels can be substituted for soil, rapid climate change is nascent, or until fresh, potable water becomes scarce.
It’s becoming clear that the most direct way humanity can triage the soil-climate-water emergency is through rapidly building topsoil, as soil is the lever for the triad. As we begin to digest the news about the role of topsoil as lynchpin in ecological health and human resource sustainability, we are waking up to world of new possibilities, including global carbon negativity, agricultural yield improvements (while simultaneously reducing inputs), flood mitigation, and biodiversity rehabilitation to name a few.
And only topsoil formation does all of these things with the amplitude to matter. Building topsoil is a deep solution that doesn’t create a multitude of new problems while attempting to solve the first one; in contrast, it actually solves many problems synergistically. Disenchanted with the failure of each silver-bullet techno-fix, humanity is beginning to realize that the resource-generating system we need most has already been invented: photosynthesis is the production and soil is the storage. If being the “toolmakers” sustained humanity through the last epoch, evolving into soil makers and water restorers might just get us from the oil age into a true solar age.
What Is Soil?
The more we learn about the living matrix underfoot the more we understand it as a vast, synergistic composite of ingredients and processes. Although soil is composed of known substances such as minerals and particles from the underlying bedrock “parent material,” organic matter from plant and animal tissues, and water, we have just begun to understand the almost magical existence of living soil born from non-living matter.
Despite its many mysteries, we do know that soil is several things:
It is the principal in our trust fund with Earth (yes, she gave us a trust – the assemblage of species and water are all part of that inheritance).
It is generative; along with water, it is the living medium from which life stems (with the influx of sunshine).
Its quantity and quality set Earth’s thermostat. Soil is where most of the carbon is: 2 percent organic matter (carbon) in the top foot of soil represents more carbon than has been produced on the planet since the Industrial Revolution began. This amount of organic matter can be built in one growing season, easily, with sound land practices. (That’s the really good news).
Soil to Oil
Solar photovoltaics, wind power, hydrogen fuel cells, smart grids, nanotech, clean coal… But what if the best news in humanity’s prospects for a more livable future is not these and other new technologies manufactured from factories, but ages-old living material manufactured by water, fungi, wind, and plants from this planet’s bedrock? (And how much more effective would our efforts be if we focused on soil creation at least as much as we do on developing new technologies?)
How will soil (and biological systems in general) again become our baseline resource-generator and storehouse? How can we enhance the soil system to sustain humanity’s resource needs while at the same time sopping up the excess carbon we’ve left in the atmosphere during the Great Fossil Fuel Party?
Back Again: Oil to Soil
A century ago we began producing our resources with oil instead of soil. Now, we’re beginning to realize just how bad a deal this was; we needed the soil not just to produce our resources renewably but to temper our climate, sustain biodiversity, deal with drought, and repair our health. But how can we possibly rebuild, say, 3 billion tons or 100 million dump-truck loads of soil in Vermont alone, maybe 1,000,000,000,000 (yes, a trillion) dump-truck loads in the heartland of the Untied States? It takes a “natural” system hundreds of years to make just 1 inch of topsoil, so we need a way to make soil that’s a thousand, maybe ten thousand times faster than the historical rate of soil formation.
Is this possible? There’s only one way to find out. Due to the sheer volume of matter needing to be converted into topsoil, any system that builds soil rapidly will utilize the most abundant and potent resources at hand, including:
Subsoil (mineral source)
Atmosphere (carbon dioxide and nitrogen source
Water (oxygen source and nutrient delivery)
Sunshine (energy source for converting plant matter into soil organic matter)
“Wastes”: manures, crop residues, woody biomass, food scraps, rock minerals, sand, and other available soil components (nutrients and organic matter)
Tools for optimally utilizing the above resources, to measure soil formation, and to provide continual feedback (technique improvement over time)
Strategies are emerging for combining these ingredients to make fertile topsoil with great speed. These strategies include nutrient cycling/composting; cover cropping; intensive, tall-grass grazing; subsoil plowing and keyline agriculture; deep-rooting perennials; biochar and re-mineralization; and bacteria and fungi inoculation. Most if not all of these strategies can be combined. Some are suitable only on the farm scale, while others are more suitable at the home scale, and strategies vary according to the type of landscape in which soil formation is applied.
The next edition of this column will highlight ways of applying these strategies on the small farm and homestead scale. In the meantime visit the following links for more information:
http://www.carbonfarmersofamerica.com/
http://www.biochar-international.org/biochar
http://hubpages.com/hub/Dynamic-Accumulators-for-Better-Soil
http://www.yeomansplow.com.au/yeomans-keyline-system.htm http://managingwholes.com/flash/wcSlideshow.htm
http://www.youtube.com/watch?v=s1lI-znogTk
¹Rough amount of topsoil volume for 10” of soil lost on 2 million Vermont acres.
²Topsoil formation represents the most likely significant action we can take for land repair, although ocean repair is equally as needed. However, there is nothing we know of yet that can heal oceans like rapid topsoil formation can heal land.
