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How Can We Build Deep Rich Soils in New England?

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This article comes from the NOFA/Massachusetts 2014 May Issue Newsletter

Jim Laurie

The work of Allan Savory and others has shown that holistically planned grazing can restore soils and wildlife habitat, improve the water cycle, feed people, and sustain rural livelihoods.  Hundreds of ranches and farms on four continents have restored land usinggrazing as their primary tool even in very dry climates with only seasonal rainfall.

What about New England?  Can grazing be used successfully here as well?

I am a restoration ecologist working with Biodiversity for a Livable Climate, a New England non-profit dedicated to building biologically diverse soils as a carbon sink to ameliorate climate change.  We invite you to our workshop “Building Deep Rich Soils in New England” at the NOFA Summer Conference in August.

Many of us complain that New England has thin and rocky soils.  Was that always true?  How much topsoil has been lost on our hillsides as forests were cut and croplands planted?  Plowing may have been difficult with all our rocks, but when it was done, much of the soil washed away.  In the last 100 years, forests have returned to New England, but are they growing as rapidly as they might if we had deeper carbon rich soils?  What can we do now to restore soil depth and health?  Can we increase organic matter to levels we haven’t seen since colonial times? Or do even better?

In Pastures of Plenty: The Future of Food, Agriculture, and Environmental Conservation in New England, Professor John Carroll at the University of New Hampshire proposes that “grazing represents, more than any other form of agriculture, the best insurance that New England has against future food insecurity.”  Well-timed, high intensity grazing can rebuild the soils and generate profits in most parts of New England, part of a local, diverse agriculture sustaining a healthy landscape.

The Importance of Animal Impact: From Buffalo to Passenger Pigeons

Many of us are aware that huge herds of millions of buffalo, pronghorn, and elk once roamed the continent, depositing several million tons of dung and urine every day as free fertilizer to soils from the Great Lakes to the Rocky Mountains.  When the herds vanished in the late nineteenth century, several feet of topsoil began to disintegrate throughout these lands. We used to blame overgrazing for desertification, but despite not having animals on them for decades, many former grassland areas have never recovered!  We now see animal impact was critical to maintaining rich soils.

Forested New England never had huge herds of wild ruminants so presumably we didn’t benefit from the migrations of millions of animals bringing their nutrients from afar.  However, 200 years ago there were several billion passenger pigeons in North America, representing about one-fourth of all the birds on the continent.  Every spring they would come north through the forests toward the Great Lakes and New England and on into Ontario and Nova Scotia, nesting for several weeks in huge roosting areas, often several hundred miles in size and 100 nests per tree.  One roost in Wisconsin was estimated at 136 million birds covering 850 square miles.  Imagine how much soil must have been deposited; several inches of bird poop might rain down in the roosting areas every time the pigeons chose to stop. Is it possible that New England soils, supplemented by migrating birds, was once much richer than it is today? 

100 years ago, Martha, the last known passenger pigeon, died in the Cincinnati Zoo.  Passenger pigeons were extinct after a century of hunting and deforestation in the northeastern United States.  Was the loss of these birds as detrimental to our New England soils as the loss of buffalo and pronghorn herds was to the prairie soils?  We may never know, but perhaps a more important question is this: What can we do now to encourage animal impact that will help us build deeper soils?

Soil Building Examples: Grazing, Earthworms, and Climate Activists.

Joel Salatin’s family moved to Virginia’s Shenandoah Valley in 1960.  Estimates of soil lost by plowing in the valley since colonial times range from 3 to 8 feet.  When Joel’s father began grazing, there were areas of bare shale rock as extensive as 100 feet in diameter.  In 2000, after 40 years of grazing, the largest of these rocky galls had been reduced to a few feet in diameter.  By 2010, he couldn't find any of these areas with less than 8 inches of new soil.  He is making a case for 8 inches of soil created within a decade using a grazing plan with high-density herd impact followed by ample recovery time. (The Sheer Ecstasy of Being a Lunatic Farmer, Joel Salatin, 2011)  

Greg Judy’s Earthworms

Greg Judy owns and leases several farms in central Missouri, grazing cattle, sheep, goats, and pigs.  Yet he considers his most important "livestock" resource to be earthworms.  Judy’s goal is 25 earthworms per square foot, which he estimates would yield 100 tons/acre/year of worm castings at no expense.  Many of Judy’s fields now have worm densities of 17 per square foot (perhaps 65 tons of castings per acre). 

Judy’s grazing strategy built on Holistic Planned Grazing, uses high-density animal herds grazing a paddock for one day then moved to the next paddock.  The goal is for animals to consume a third of the grass in the paddock and trample the rest into the soil to feed earthworms and soil microbes.

Importantly, he does not use de-worming agents and other chemicals poisonous to soil biota like dung beetles, whose beneficial impact is significant.  Dung beetle holes help create paths for earthworm activity and other soil biota, and the dung dried out by beetle activity and taken below ground reduces fly populations.  Pat and Dick Richardson, Ecology Professors at University of Texas, have estimated that dung beetles following dense herds of cattle can bury a ton of wet manure per acre overnight.

From soil depth measurements, Judy estimates that his grazing practice built 3 inches of soil in many fields in 4 years.  The trampled grass, animal manure, and worm casting mix makes very rich topsoil.  Dry worm castings are typically 70% organic matter and 30% minerals.  Estimating organic matter of Judy’s new soil conservatively at 8%, three inches of new soil would represent 15 tons of organic carbon added per acre in 4 years.  That is 3.75 tons organic carbon per acre per year.  This new soil should hold 60 tons more water per acre than before, a difference of about 14,000 gallons/acre. 

Dung beetles carrying animal dung balls as much as three feet downward and the increased flow of sugars from healthy plants to support mycorrhizal fungi scouting minerals will also increase soil organic matter and therefore, soil carbon. 

Conventional soil scientists generally consider 1 ton of carbon sequestered per acre each year to be significant, but when these biological pathways are added the true soil carbon sequestering potential may be much larger.

His two books discuss these as integral to profitable grazing operations. No Risk Ranching: Custom Grazing on Leased Land (2002) describes how he started his grazing business with little capital.  Comeback Farms: Rejuvenating Soil, Pastures, and Profits with Livestock Grazing Management (2008), worth reading several times, focuses on Holistic Planned Grazing using high density and multi-species grazing with movable electric fences.

 

Greg’s excellent presentation Holistic Resource Management for Profitable & Sustainable Production of Crops and Livestock, at the Virginia Association for Biological Farming in 2011, includes slides showing his Green Pastures Farm and observations of soil biodiversity. See more at www.youtu.be/W6HGKSvjk5Q and www.greenpasturesfarm.net.

Bringing Soils Back to the City - Somerville Climate Action “DePaving the Way”

Somerville Climate Action (SCA), a non-profit in Massachusetts alerting the public to the dangers of Climate Change for over a decade, has gone beyond emissions reduction, advocating the growing of local food.  They understand that building soil takes carbon out of the air and puts it back in the ground, but very urban Somerville is about 77% impervious surface. 

In 2010, Somerville had several floods because rainwater had nowhere to go, prompting SCA to start its depaving campaign. Finding several homeowners with asphalt and concrete backyards they no longer wanted, SCA responded with 30 volunteers and tools to “DePave the Way.”  Several depaved yards have become gardens growing food for local residents.  The City supports these efforts as a way to help reduce flooding, a constant concern. 

First depaving project in October 2010: www.vimeo.com/22830594 www.facebook.com/pages/Somerville-Climate-Action/63128756752?id=63128756752&sk=photos_stream

Urban and Suburban Landscapes: Turf Grass Lawn or Local Agriculture?

Many suburbs are dominated by grass lawns requiring quite an investment to maintain what is essentially a monoculture.  Turf grasses generally have shallow roots and often need watering, even in our moist climate.  The campaign against dandelions is another counter-productive example.  Dandelions feed wildlife and their taproots bring calcium from deep in the soil to the surface.  Higher calcium encourages clovers, which add free nitrogen to your soil.

Many forms of agriculture are now returning to cities and towns.  Chickens, goats, and even pigs are being raised in places that had not seen them in many decades.  Imagine growing vegetables in your front yard: you can pick your dinner as you go from car to house.  One home in Woburn grows most of its own vegetables.  Neighbors now follow their example and grow home gardens of their own.

Some city folks don’t like grass-eating geese on their lawns.  Geese need large open areas to take flight and are easily discouraged by blueberry bushes and tall growing tomatoes. The Woburn house doesn’t get geese, but many turkeys stop to see the plantings.

Hope to see you at our Building Soils Workshop at the NOFA Summer Conference!

Jim Laurie is a biologist and chemist who built wetlands to treat sewage and chemical wastewater working with John Todd, has studied restoration strategies in California salmon streams and redwood forests, and worked with graziers in Texas, Montana, and New England.  Biodiversity for a Livable Climate (BLC) paved the way for Allan Savory to come to Boston twice in 2013, and promotes soil building as the best antidote to climate change while providing many other benefits mentioned above. 

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