My Pile: Carbon Farming

My pile is a homegrown solution to a global problem — climate change caused by man-made increases in greenhouse gas emissions.

True, the vapors ever-rising from its midst are proof that my pile passes a lot of gas of its own making.

My pile is, after all, a hot mess of carbon-laden leaves spiked with nitrogen-rich combustibles. Its main purpose in life (and death) is to break down complex molecules into more elemental, reusable parts, as quickly and robustly as my meddling efforts make possible. A byproduct of that energetic process is greenhouse gases, mostly in the form of carbon dioxide and no doubt some methane as well.

A classic view of my pile in action, this on a frosty fall morning.

A classic view of my pile in action, this on a frosty fall morning.

Ever-increasing levels of those noxious fumes are now playing havoc with what has been a very human-friendly climate these past few millennia, give or take an ice age or two, or even this long slog of a snowbound winter.

But here’s some research from an EPA report from 2010 that supports the value of a compost pile as a way to lock up some of that excess carbon dioxide or otherwise offset its potentially ghastly effects on our environment. Living as I do in a fully four-season climate, hard by the intricate meeting of saltwater and shore, the weather forecast is a constant reminder of how delicate the balance is between comfort and crisis, near term and long.

I’ve extracted a few relevant bits from the footnote-laden report, but the conclusion to me is that my pile saves more energy and stashes away more carbon than it gives off in excess greenhouse gases.

“This guidance document describes the development of composting emission factors for EPA’s Waste Reduction Model (WARM). Included are estimates of the net greenhouse gas (GHG) emissions from composting of yard trimmings and food scraps, as well as mixed organics.

…. During this decomposition, approximately 80 percent of the initial organic matter is emitted as CO2. The remainder of the organic compounds eventually stabilize and become resistant to further rapid microbial decomposition (i.e., recalcitrant).

…. Significant evidence exists that compost contains stable compounds, such as humus, and that the carbon stored in that humus should be considered passive when added to the soil because it breaks down much more slowly than crop residues.

…. Although EPA understands that generally compost is applied for its soil amendment properties rather than for pest control, compost has been effective in reducing the need for harmful or toxic pesticides and fungicides.

…. Manufacturing those agricultural products requires energy. To the extent that compost may replace or reduce the need for these substances, composting may result in reduced energy‐related GHG emissions.”

On a modest backyard scale, my pile is a farm factory. Its end product (more like a beginning) is humus, loaded with stable carbon molecules and other nice-to-have nutrients. These reconstituted elements are bound up in a loamy matrix of organics, teeming with life. This rich mix of newly made earth has a multiplier effect when spread across the land, leading to other eco-friendly results with lasting benefits, like more plant growth (photosynthesis = oxygen ), less water use and reduced need for chemical fertilizers and pesticides.

In “The Soil Will Save Us,” Kristin Ohlson writes of reclaiming her worn-out suburban lawn through the use of leaf mold and compost, then uses the experience to tell the larger story of “How Scientists, Farmers, and Foodies are Healing the Soil to Save the Planet.”

She reports: Carbon Farming. That’s the new thing.”

… Sometimes they called themselves microbe farmers, aware of the billions of tiny creatures that they couldn’t see but that scientists told them were at work in the soil. Sometimes they called themselves carbon farmers, knowing that it was the carbon that was making their soils richer, moister and darker. Some had been following the work of scientists who said that this kind of farming accelerated the removal of carbon dioxide from the atmosphere via photosynthesis and could slow and maybe even turn back global warming.”

I am a compost farmer as much as I am a suburban dad who keeps a nice lawn for the kids to play on and a garden with fresh organic vegetables to put on the table.

My pile is my back 40, and its yearly crop of rich dark compost, teeming with life and recycled nutrients, chief among them repurposed carbon, is what makes my garden and lawn so prolific in the six months of the year when our world is green and growing.

My pile, a hot mess of carbon processing...

My pile, a hot mess of carbon processing. It’s a backyard factory that produces rich new earth.

Ohlson provides more of a global view, from the ground up:

Plants remove carbon dioxide from the air and, combined with sunlight, convert it to carbon sugars that the plant uses for energy. Not all the carbon is consumed by the plants. Some is stored in the soil as humus … a stable network of carbon molecules that can remain in the soil for centuries. There in the soil, the carbon confers many benefits. It makes the soil more fertile. It gives the soil a cakelike texture, structured with tiny air pockets. Soils rich in carbon buffer against both drought and flood soil is also rich with microorganisms – an amazing 6 billion in a tablespoon – that can disarm toxins and pollutants that soak into the soil through the rain.”

Ohlson makes the case that composting on a scale both large and small is one of the most effective, scalable ways to reduce the amount of carbon emissions entering the atmosphere.

Other scientist writers, such as David R. Montgomery in Dirt: The Erosion of Civilizations, and Jared Diamond in Collapse: How Societies Choose to Fail or Succeed, have made similarly convincing arguments that when a civilization’s soil goes bust, that culture is toast.

“Ohio has lost 50 percent of its soil carbon in the last 200 years. But in areas of the world where cultivation has been going on for millennia, soil carbon depletion is much higher – up to 80 percent or more. Altogether, the world’s soils have lost up to 80 billion tons of carbon…. Even now, land misuse accounts for 30 percent of the carbon emissions entering the atmosphere,” writes Ohlson.

“With good soil practices, we could reverse global warming.”

To shift from thinking globally to acting locally, so about how much does a backyard compost pile contribute to carbon sequestration? The best account I can find is an article on The Global Citizen website by Donella H. Meadows, an adjunct professor of environmental studies at Dartmouth College and director of the Sustainability Institute.

In “How Much Greenhouse Gas Does Your Garden Cut,” she relates relates some number-crunching done by Dr. Jonathan Foley, an environmental scientist at the University of Wisconsin, for his brother David’s .4 acre organic garden — a plot about the size of my backyard.

Over 10 years of composting and other sustainable gardening practices, David and his wife, Judy, have increased the the percentage of organic matter in their communal garden in Maine from 1 percent to 7.7 percent.

That impressive boost translates to an increase of 2.2 pounds of carbon in every square foot of their garden. Add it all up and, according to Jon Foley’s back-of-the-envelope calculations, his brother has removed over 38,000 pounds of carbon from the atmosphere — 19 tons — over the past 10 years.

“The average American releases 6 to 6.5 tons of carbon into the atmosphere each year,” Foley reports, “So you have offset about three years of an average American’s emissions.”

My pile and backyard garden are surely of a more modest scale than the Foleys’ communal efforts, but composting surely reduces my carbon footprint in similar ways, and that’s a good step in the right direction.


My Pile: Ashes to Ashes to ‘Black Gold’

After a long, cold week of work and further digging out from an additional dumping of snow, I finish up Saturday morning errands and indoor chores, pondering my pile all the while.

I glance across the backyard through a bedroom window. Like the ground that surrounds it, my pile is still thick with snow, though I can see from afar several craggy holes across the top created by the furnace of heat-producing microbes within. A good sign on a frigid winter day.

My pile, in the process of shrugging off its mantle of snow.

Still, I worry that the weight of the snow covering my pile will squeeze the life out of it.

Through the fall and into these winter months, my pile’s lung-like movement up and down has amazed me. It absorbs the blankets of leaves and buckets of seaweed I add to it, rising high. A day or week or so later, it settles back into itself. My pile is like the science experiment taught to grade schoolers: Here’s a glass of water and here’s a shaker full of salt. Add all that salt to the water, stir it up and wonder: where did all that salt go?

So now I wonder: will all the water locked up in the snow douse my pile’s inner fire? Or will the water melt into sips that will sustain my pile’s inner workings until the sun is potent enough once again to boil it off?

Like my pile, my musings about it are anything but dormant. I enjoy provoking it and prodding it along in all seasons. My pile, even in winter, is my favorite hobby, and more.

I gather dustballs from under the beds and empty the fireplace of its ashes. Rather than dump the resulting brown paper bag half-full of indoor detritus into the kitchen trash bin, I decide to sprinkle it all across the top of my pile. My fast-filling bucket of kitchen scraps has nowhere to go at the moment except into cold storage in the tool shed, but perhaps this dusty blessing of gray ash and carbonized wood will help further melt the snow.

I bundle up and trudge out across the snowpack to my pile. Setting the bag of ash and furry dander aside, I pick up the rebar rod I keep leaned up against the back side of the tool shed. I pierce my pile 20 or so times, from all angles and sides, circling its flanks like a caveman finishing off a woolly mammoth. I focus my prodding on places still thick with snow.

I’m wagering that my pile can continue to thrive under its blanket of insulating snow, and stabbing it a few more times will activate the now dormant areas of the pile underneath.

A 7-ft. length of ribbed rebar is a handy way to prod my pile, creating airshafts through and through.

A 7-ft. length of ribbed rebar is a handy way to prod my pile, creating airshafts through and through.

It’s a good, quick workout, and before long I’ve created a score of shafted pathways for meltwater to soak down through the cold, dry compartments of leaves that surely surround the areas into which I’ve forked in supplies of fresh green rotting stuff. As all the compost guidebooks say, a heap of compost should be like a damp sponge.

I lean over the log wall to peer inside one of the vent holes, rimmed with hoar frost. Within is a cavern of space, creating in part by the pile subsiding and its ceiling of icy snow rising. Like some salt dome down South, my pile’s covering of snow could easily collapse upon itself into a sinkhole of snow. But I figure the leaves inside have now fallen to about the level of the log walls; I decide to add more snow, if only to keep my pile high enough to pee on it in privacy.

I set the bar aside and pick up the wide snow shovel to scoop swaths of crusty powdery snow from an ever-widening ring around my pile, tossing the mushed-up snow across the top. I stop to heft a few chunks of snowbergs to plug the biggest vent holes. My aim is not to smother my pile but to seal any escape hatches of heat. A thermal blanket.

A dozen or so helpings of scrapped-up snow soon reforms my pile into a crested white butte between log walls.

Happy and panting with my handiwork, I grab the bag of ash and furry dustballs. I try to stay upwind as a tilt and flick the bag full of soot across the top of my pile. Chucks of charcoal tumble down the front face, but most of the ash swirls and sticks onto the snow covering my pile.

My pile, freshly adorned with more snow and a blessing of ash.

My pile, freshly adorned with more snow and a blessing of ash, containing nutrients from plant materials to be recycled back into the earth from whence it came. Truly, ashes to ashes…

This stubble of gray will gather sunlight and melt into my pile, the ash and flecks of wood coal sinking slowly downward to add its carbon and nutrients to the mix, the warm wet water vapor rising to meet it from below.

I’m sparing in the addition of wood ash, a very caustic material, to my pile. “Small amounts are fine,” advises Mike McGrath in his “Book of Compost.” “The ashes of high-quality hardwoods do contain high levels of calcium and potassium, which are essential plant nutrients. But we are talking small amounts. No more than a cup of ashes mixed into a 4 x 4 x 4-foot bin.” McGrath would rather see wood ash sprinkled across the lawn or garden (instead of lime) to raise the pH level of the soil, which tends toward the acidic in areas of plentiful rainfall. This I do, pacing across the yard as I jiggle wood ash and bits of charcoal from the paper bag.

McGrath expounds on the qualities and uses of wood ash on the website “Julia Gaskin, a Land Application Specialist for the University of Georgia Extension Service, explains that ash from good quality hardwoods contains a very nice amount of potassium; at least 3% by weight. Also known as potash, this is the “K” in the fabled N-P-K scale of plant nutrients—the Dow Jones of Horticulture! Potash improves root health and strengthens the very cellular structure of plants, helping them resist all kinds of stresses.”

Here’s more about potash, from Dan Sullivan, soil scientist with the Oregon State University Extension Service, quoted in an article by Carol Savonen on the Extension’s website. “In the 18th century, the benefits of ash-derived potash, or potassium carbonate, became widely recognized. North American trees were felled, burned and the ash was exported to Great Britain as ‘potash fever’ hit. In 1790, the newly-independent United States of America’s first patented process was a method for making fertilizer from wood ash (U.S. patent number 1: “An improved method of making pot and pearl ash).”

It’s fascinating to realize that processing wood ash was once so cutting-edge technology that it will forever be No. 1 on the list of American ingenuity. I am also intrigued by accounts of how the messy remains of my fireplace can turn my pile into a rich deposit of “black gold.”

Here’s what NPR has to say about it in a Science Friday story by Ira Flatow:

“Researchers say that adding charcoal to soil may provide more benefits for long-term soil quality than compost or manure…

“Poor quality soil. It’s a problem for farmers around the world. Dirt stripped of nutrients by years of over-farming and chemical fertilizers. Well, this week there’s new evidence that an old farming practice traced back at least 1,500 years to tribes in the Amazon basin can give new life to nutrient-poor dirt. It’s called “black gold agriculture.” The idea is really simple. You add charcoal from burned organic matter to the soil and the dirt holds on to nutrients and produces lots more crops.”

Flatow interviews Dr. Mingxin Guo is an assistant professor in the Agriculture and Natural Resources Department at Delaware State University in Dover.

FLATOW: “Let’s talk about poor quality soil, a big problem around the world. Why is that?

Dr. GUO: Yes. So deterioration and chemical degradation is a severe and worldwide problem. It is expressed as soil compaction, poor tubes, surface crafting(ph), slow water seepage, low water draining, low nutrients and a low nutrient retaining, and also decreasing crop productivity. This problem is mainly caused by long-term chemical fertilizer application and mechanical tillage. The level of organic matter determines the quality of our soil. All the soils have high organic matter content, say, six to 15 percent. But soil plowing makes the organic matter decompose quickly, while chemical fertilization doesn’t incur any external organic matter adhesion. So year after year, farmland soils become low in organic matter and the quality turns poor. So currently, most of farmland soils have organic matter content lower than three percent.

FLATOW: Ah. So what does adding charcoal to the soil, why does it make it a better fertilizer?

Dr. GUO: Charcoal is a fine-grained, porous black carbon, and it is generated from plant materials. And it is non-toxic to plants. So there are many tiny pores in charcoal. So once applied to soil, the pores will allow air to diffuse into the soil. Plant roots need the air to breathe. And in the meanwhile, the tiny pores will hold water and nutrients and later supply it to plants. More important, unlike other organic fertilizers, charcoal is very stable and it will not decompose to carbon dioxide. So once applied, it will stay in soil for hundreds to thousands of years. So to summarize, the high stability and porosity make charcoal a better fertilizer than other organic materials.”

FLATOW: … And so, I know this is an ancient technique that was discovered in pre-Columbian tribes from the central Amazon. They were doing this 1,500 years ago.

Dr. GUO: Yes. We actually, we learned this lesson from the pre-Amazon people. An archeological event disclosed the fertile, charcoal carbon-rich and highly productive soil in the central Amazon basin. And later, scientific studies revealed that this fertile soil was fertilized by the Amazon people 1,500 years ago with char produced by smothering plant debris and annual bulbs(ph).

FLATOW: Ah. So the char, the fertilizer they made, the char they made 1,500 years ago, was still working?

Dr. GUO: Yes. The soil is still highly productive, even after 1,000 years of crop cultivation without any other fertilization.”

My pile is a long way from an ancient field in the Amazon jungle, but I subscribe to the theory. As I tend my garden beds and lawn and come across a chunky bit of charcoal, I think of a slash and burn farmer from a millennium before, and thank him.

Ash and bits of charcoal gather sunlight on my pile and add their own properties to the mix.

Ash and bits of charcoal gather sunlight on my pile and add their own properties to the mix.

Late in the day I step out onto the back porch to let the dog out for a pee. The sun is low through the trees and casts its light across the top of my pile. There, I see a wisp of steam backlit by a sunbeam. My pile has already punched its way through its new mantle of snow.

Life always finds a way, even on the coldest day of winter.