By Lambert Strether of Corrente

As long-time readers, at least, may know, I’m a fan of permaculture, and did a lot of gardening using permaculture principals. I started at the time of the Crash, working on the assumption that I should need to learn to grow my own food on my own patch. As my situation improved, I discovered that what I really wanted to do was sit and work in the midst of flowers, listening to birds and pollinators, but I designed that garden along permaculture principles, too (most importantly stacking functions). Now (hat tip reader Cal2) the release into the public doman of permaculture co-developer Bill Mollison‘s Permaculture: A Design Manual gives me the opportunity to return to this topic once more. Soil fans, listen up!

What, you may ask, is permaculture? Here is what Mollison wrote in 2002[1]:

Permaculture (permanent agriculture) is the conscious design and maintenance of agriculturally productive ecosystems which have the diversity, stability, and resilience of natural ecosystems. It is the harmonious integration of landscape and people providing their food, energy, shelter, and other material and non-material needs in a sustainable way. Without permanent agriculture there is no possibility of a stable social order. Permaculture design is a system of assembling conceptual, material, and strategic components in a pattern which functions to benefit life in all its forms. The philosophy behind permaculture is one of working with, rather than against, nature; of protracted and thoughtful observation rather than protracted and thoughtless action; of looking at systems in all their functions, rather than asking only one yield of them; and of allowing systems to demonstrate their own evolutions.

Now, to some that definition, if definition it be, may seem a little fuzzy around the edges; and Permaculture: A Design Manual sometimes reads like brilliant work of the imagination, rather than a manual. However, more recent studies have subjected the principles presented by permaculture co-developer David Holmgren to testing, and found them to pass. (See “Permaculture—Scientific Evidence of Principles for the Agroecological Design of Farming Systems,” Sustainability). It is easy to see, however, that a factory farm or an Iowa field optimized for High Fructose Corn Syrup are the opposites of permaculture.) In this post, I will look at permaculture and the soil, remind readers of the role that soil can play in carbon capture, and finally present an honest-to-gosh academic study that shows that permaculture, by producing healthy soil, aids in carbon capture and thus in mitigating climate change.

Permaculture and Soil

From Chapter 8 of Permaculture: A Design Manual, Mollison on soil:

Soils defy precise treatment, as their structure (and permeability), organic content, gaseous components (some derived from the atmosphere, some from processes within the soil, and some exhaled from the sediments below), minerals, pH, and water (or rather solute status) changes from hour to hour with soil depth and treatment, and in response to micro elevations. Added to this is the fact that many soils are originally complex mixtures derived from a variety of rock types and that they may have had a very long and varied history. Soil science concentrates very much on what is there (classifications), but not on how to evolve soil. Often it is left to amateurs—gardeners and farmers—to create good soil by water control, modest aeration, and plant and animal management. Farmers and gardeners seem to be so often the practical, innovative, experimental, successful group (while often ignored by academics) that I despair of esoteric knowledge ever preceding effective action. Very few farmers can persuade a group of scientists to assess their apparently successful soil trials. It is past time that we assessed whether more “science” is not being done by outdoor people than by scientists who (like myself) more often collect the results of others than generate them by example. Science is good at explaining why things work, and thus making skills teachable. It is not so good at initiating field work, or in training people already in the field to work effectively. The only places where soils are conserved or increased are: In uncut forests;

Under the quiet water of lakes and ponds;

In prairies and meadows of permanent plants; and

Where we grow plants with mulched or non-tillage systems. These then are the core subjects of sustainable societies of any conceivable future. They are not, you might notice, the subjects most taught in the agricultural colleges or forestry courses of the recent past, nor do they occupy the minds of politicians, investment bankers, or TV stars.

Here is a high-level and pragmatic summary of Mollison’s ideas:

I refer to the definition as used by Mollison as a combination of two words; Permanent and Agriculture, permanent agriculture = Permaculture. Mollison’s main criticism of conventional annual based agriculture was that it was not sustainable because nothing about it was permanent. Because of mass soil cultivation and petrochemicals used in conventional agriculture, topsoil is continuously mined away and biodiversity loss. A constant state of diminishing returns. His idea was to create a system of permanent agriculture. It is also commonly referred to a design system based on observing patterns in nature.

(Note the definition: “Permanent agriculture,” made permanent in the soil.) All I can say is that anecdotally — and not on the scale of even a small farm — I greatly improved my soil using permaculture principles. Not that everybody should take this approach, but I ripped out my lawn by removing all the grass, added layers mulches, and sheet-mulched[2] everything (not for everybody!). When I started, my soil was dark, clay-y, and repellent to the touch; when I finished, my soil was lighterc-colored, almost fluffy, and there were a lot of worms. Plus the plants were happy.

The World Economic Forum (!) recognizes the importance of “permanent agriculture”:

Healthy soil leads to healthy humans. Sir Albert Howard, one of the forethinkers of organic agriculture and composting, explored this link in the early 20th century. Sir Albert recognized soil as a living organism, not just as an exploitable commodity, as we do nowadays. Current agriculture, which consists of monocultures and extensive use of fertilizer, pesticide and herbicide, has caused a significant loss of biodiversity, has decreased soil quality and has polluted the environment…. Our soil is losing its fertile humus layer, which is resulting in even more fertilizer use. These negative trends are accelerating climate change, leading to more wildfires, droughts and floods. It’s not just an organic farming technique, but rather a philosophy that teaches respect for the environment and a reflective approach towards modern capitalist consumption, locality and food, more in sync with nature. Permaculture’s goal is to nourish humans while enhancing biodiversity and increasing soil quality by adding humus.

I’m going to skip the WEF thesis, which is that tech needs to be integrated to permaculture for scale; but it’s amazing to me that permaculture’s concepts have reached Davos (for good or ill).

Soil as Carbon Capture

To refresh readers’ memories, soil is a significant carbon sink, and soil produced by permaculture is a much more effective carbon sink than soil produced by monocultures. From Nature, “Soil carbon sequestration accelerated by restoration of grassland biodiversity“:

Agriculturally degraded and abandoned lands can remove atmospheric CO2 and sequester it as soil organic matter during natural succession. However, this process may be slow, requiring a century or longer to re-attain pre-agricultural soil carbon levels. Here, we find that restoration of late-successional grassland plant diversity leads to accelerating annual carbon storage rates that, by the second period (years 13–22), are 200% greater in our highest diversity treatment than during succession at this site, and 70% greater than in monocultures. The higher soil carbon storage rates of the second period (years 13–22) are associated with the greater aboveground production and root biomass of this period, and with the presence of multiple species, especially C4 grasses and legumes. Our results suggest that restoration of high plant diversity may greatly increase carbon capture and storage rates on degraded and abandoned agricultural lands.

Of course, this isn’t a magic bullet (see Dirt as a Carbon Sink? and associated commentary at NC). And now to the promised study:

Permaculture, Soil, Carbon Capture, and Climate

As it turns out, permaculture can be shown to improve carbon capture. From “Effects of Permaculture Practices on Soil Physicochemical Properties and Organic Matter Distribution in Aggregates: A Case Study of the Bec-Hellouin Farm (France),” Frontiers in Environmental Science (2018). From the abstract:

The limitations of conventional agriculture have accelerated the need for a transition to an environmentally and economically sustainable agricultural model. In this regard, the role played by soil organic matter (SOM) is key. Here, we aimed to study the impact of permaculture and biointensive micro-gardening practices, characterized by intensive cultivation, the use of large and localized organic inputs and the non-use of mineral fertilizers and pesticides, on soil physicochemical properties and SOM distribution in aggregate-size fractions. The physicochemical properties of soils in permaculture farming implemented for 7 years were compared with a soil under pasture. A soil experiencing conventional agriculture practices in similar geopedoclimatic conditions was simultaneously studied. Soils were separated into four aggregate-size fractions, into which organic carbon (OC) concentrations have been measured. The major soil physicochemical properties were measured on the bulk soils. The concentrations of total OC and nitrogen (N) in bulk soils were higher under permaculture practices , due to significant inputs of manure and compost, resulting in higher concentrations of the bioavailable nutrients…. Thus, permaculture practices enable the storage of additional C in soils.

Summing up in less dense prose, from Yale Environment 360:

Absent carbon and critical microbes, soil becomes mere dirt, a process of deterioration that’s been rampant around the globe. Many scientists say that regenerative agricultural practices can turn back the carbon clock, reducing atmospheric CO2 while also boosting soil productivity and increasing resilience to floods and drought. Such regenerative techniques [like permaculture –lambert] include planting fields year-round in crops or other cover, and agroforestry that combines crops, trees, and animal husbandry. Recognition of the vital role played by soil carbon could mark an important if subtle shift in the discussion about global warming, which has been heavily focused on curbing emissions of fossil fuels. But a look at soil brings a sharper focus on potential carbon sinks. Reducing emissions is crucial, but soil carbon sequestration needs to be part of the picture as well, says [Rattan Lal, director of Ohio State University’s Carbon Management and Sequestration Center]. The top priorities, he says, are restoring degraded and eroded lands, as well as avoiding deforestation and the farming of peatlands, which are a major reservoir of carbon and are easily decomposed upon drainage and cultivation. He adds that bringing carbon back into soils has to be done not only to offset fossil fuels, but also to feed our growing global population. “We cannot feed people if soil is degraded,” he says. “Supply-side approaches, centered on CO2 sources, amount to reshuffling the Titanic deck chairs if we overlook demand-side solutions: where that carbon can and should go,” says Thomas J. Goreau, a biogeochemist and expert on carbon and nitrogen cycles who now serves as president of the Global Coral Reef Alliance. Goreau says we need to seek opportunities to increase soil carbon in all ecosystems — from tropical forests to pasture to wetlands — by replanting degraded areas, increased mulching of biomass instead of burning, large-scale use of biochar, improved pasture management, effective erosion control, and restoration of mangroves, salt marshes, and sea grasses. “CO2 cannot be reduced to safe levels in time to avoid serious long-term impacts unless the other side of atmospheric CO2 balance is included,” Goreau says. Scientists say that more carbon resides in soil than in the atmosphere and all plant life combined; there are 2,500 billion tons of carbon in soil, compared with 800 billion tons in the atmosphere and 560 billion tons in plant and animal life. And compared to many proposed geoengineering fixes, storing carbon in soil is simple: It’s a matter of returning carbon where it belongs.

Which, as I have shown, permaculture can do.

Conclusion

Of course, I haven’t done the arithmetic to show a tranche of C being returned to the soil through a global permaculture effort (or that permaculture could scale to feed the world; my back-of-the-envelope calculation says it can). And I haven’t said how long this would take, or what would systems would have to change to make it happen. But I can ask a simple question: If you have a lawn or a garden, what are you doing to return carbon to the soil?

NOTES

[1] From Wikipedia: “In 1987, Mollison taught the first [Permaculture Design Course (PDC)] that was offered in India. By 2011 there had been over 300,000 such graduates practicing and teaching throughout the world.” Which is a good number; there are many, many examples online, though none of them seem to be covered as stories; here’s a random pick from Jordan; another from the Philippines; another from Malawi. Permaculture proceeds by a sort of apostolic succession, as PDC graduates start their own businesses and teach PDCs themselves. This does seem a bit like multilevel marketing; on the other hand, it’s necessary to make a living in order to spread the word. Here is a critique of what might be called “vulgar permaculture.” For example, you don’t have to mulch everything, and you don’t have to swale everything. Note that both “protracted and thoughtful observation” and “looking at systems in all their functions” militate against such practices.

[2] I was very lazy and cheap. I assume a rich, “lasagna-style” sheet mulch system would give much better results.