I recently attended the Nature-based Solutions and Soil Farming Conference in Brisbane to learn more about carbon in soil, its permanence and whether it can reasonably be considered a ‘permanent’ carbon sink and if so, in what context.

The purpose of attending the conference, was to better understand the status and potential for integration of soil carbon into a building sector biodiversity and carbon benefit certification process being considered as part of the new NaturePositive+ Standard in final stages of development at Global GreenTag.

During the conference, I was surprised by how little reference or acknowledgement there was to the massively important work done in biodiversity and carbon-positive agriculture in our ‘recent past’ by several generations of Australian farmer/scientists. I was aware if this work because of my own history in environmental activism and sustainability, but also because of the work of my own father Dr Sydney Baggs, who I owe my knowledge of the Yeomans’ work and my later interest and direct engagement with, and graduation from, a ‘Fundamentals of Permaculture’ course delivered by Bill Mollison in the early 80s.

In combination, these agricultural inventions and ideas have a much more important role to play today as the world turns to nature-based solutions for carbon drawdown from the atmosphere, especially as we look towards reversal of the damaging impacts of modern agricultural practices that use synthetic fertilisers, insecticides, and herbicides together with mono-cropping, thereby sterilizing the soil and land of life, and commonly resulting in resorting to tree-clearing to expand production.

These practices put agriculture in the firing line for increasing environmental damage and climate change. Reversing these practices using soil carbon farming has been underway in a small and growing section of the farming community but will need to become more widespread if farmers are to become part of the solution instead of the problem.

Let us review some history to understand how we got to where we are and then we will look at how and where soil carbon can fit into a built environment net-zero and net-positive future for the building sector.

‘Permaculture’ was developed in the 70s and 80s by two Australians, David Holmgren and Bill Mollison, and launched publicly in 1978 with their book 1978 ‘Permaculture One: A Perennial Agriculture for Human Settlements’ and further developed and later spread internationally also by Geoff Lawton.

Permaculture combined the almost unacknowledged, but critically important underpinning work done by P.A. Yeomans in the 40s and 50s and later by his son Alan J. Yeomans and their ‘Keyline’ agricultural system with its unique contour drainage and deep-tine plowing system the ‘Keyline Plow’ that rips soil to down to typically between 600 – 650mm without disturbing the surface, to aerate and let water into the deep subsoil, to both facilitate water storage and also encourage micro-organism growth to greater depths. The importance of this will become clear later in this article.

Alan Yeoman first published his scientific paper entitled ‘The Agricultural Solution to the Greenhouse Effect in 1990 at the Esalen Conference on Sustainable Agriculture in California and in doing so became one of the first to introduce soil carbon as a concept and solution to climate change as well as including it in his definition of Sustainable Agriculture in that paper as:

1. “1. A system in which the degradation of the soils of the country is reversed and we see a constant increase in the depth of soil structures and a constant increase in the mass of micro-biological activity within the soil.
2. It is a never-ending cycle of growth, death, decay, and re-growth where the extracted minerals are returned to the soils – not dumped in the rivers and oceans or huge waste 1its. The soils’ mineral wealth must be part of a constant re-circulating chain of events.
3. It is an agricultural system where chemical plant stimulants i.e., soluble fertilisers from fossil fuels, will have no significant contribution and where deadly herbicides, pesticides and fungicides are no longer needed. The role of man-made chemicals must at least be a temporary measure administered as medicine paralleling the human use of medicine. Some chemicals possibly could be a supplement with the test being that the final eco-system must be improved by their use, soil must be richer and with more life; water and air must be cleaner and food more nutritional. If not, they fail the test.
4. And finally, Sustainable Agriculture is a system where agriculture enhances the availability and purity of water systems, not destroys and pollutes them.”

International work by Zimbabwean ecologist and farmer Allan Savory demonstrated outcomes relevant to Australia’s degraded lands and may also have influenced local early adopters of new sustainable grazing techniques in his 2013 TEDx Talk How to green the world’s deserts and reverse climate change where he identified that consistent degradation of our soils was leading to ‘Desertification’ and approximated from satellite images that 2/3 of the earth is desertifying. He held that its causes were a combination of climate change and human endeavours such as agriculture, especially current grazing, mining and logging practices.

Allan was able to reverse this degradation and return disused, dry, depleted lands into functional, lush, green pastures in his native Zimbabwe and elsewhere. He demonstrated that the key was to allow dense herds of livestock to graze the land intensively but for very short periods, mimicking the way that native animals once grazed in herds, removing dead grasses that would otherwise prevent new grasses growing, fertilising the land, creating mulch and subsequently stimulating plant growth and restoring streams and aquifers.

Another of the leading lights Australian soil carbon farming is zoologist, farmer and honorary Senior Lecturer at ANU, Dr Charles Massy OAM, who championed Regenerative Agriculture and challenged traditional farming practices within Australia by implementing holistic grazing methods and transforming his own 2000-hectare property back to health after years of drought and overgrazing. His book entitled ‘Call of the Reed Warbler: A New Agriculture – A New Earth and his subsequent 2018 TED Talk ‘How Regenerative Farming Can Help Heal The Planet and Human Health’ provided the next insights from an experienced farmer as to how these principles can be taken into broadscale grazing.

Permaculture advocate Jeff Lawton also identified alternative ways to reverse desertification. Commencing in 2000, the Permaculture project and ‘Greening the Desert’ demonstration site and education centre is located between the villages of Al Jawfa and Al Jawasreh in the Jordan River Valley and exemplified the beneficial impacts of a permaculture-based integrated farming approach in a severely arid climate. Incorporating organic agricultural production, water and waste management, soil amelioration, renewable energies, environmental sustainability and ecosystem diversity, his ‘Greening the Desert’ video produced after 10 years of that project work between 2009-2019, graphically illustrates the power of the combined utilization of Keyline and Permaculture principles to successfully reverse desertification, providing a unique model for self-sustainable farming that is also relevant to Australia.

What does all this have to do with the building sector?

Well let us now look at that aspect directly. To do so though we need assume one or more of the beneficial farming practices mentioned above are being practiced, and delve more deeply into soil, microbiology and Australia’s carbon market.

At the Soil Carbon Farming Summit, I learnt that:

1. In soil, there are 2 kinds of micro-organisms (MOs):

 –     the types we think of when we typically think of soil, they are moisture sensitive, and when they die, they excrete C02, so if there is a drought or desertification takes over much of the soil carbon is lost to the atmosphere, obviously a climate problem;

 –     then there are other types that in their normal lives absorb nutrients and excrete mineralised forms of carbon that don’t release C02 if the micro-organisms (MOs) die.

This second form of soil carbon mineralisation MOs are unfortunately most vulnerable to Nitrogen based fertilisers, but when these fertilization techniques are ceased and alternative nutritional practices employed, these MOs bounce back, especially if the soil or seeds are purposefully re-inoculated with the preferred MO species as are now commercially available. Add directly to soil with seeds, either crop or grass, these MOs can tilt the balance towards more permanent soil carbon fixing, even in the presence of cropping and grazing;

2. Subject to depth of tilling, agriculture techniques, species planted and application of MOs, soil carbon typically tracks down to 600-900mm, commonly to 1500mm and with species like Mitchell Grass and other native grassland species combined with selective and planned grazing, can go down to 3 metres.

At these greater depths the soil is not as prone to drought as one would imagine. Even regular cropping typically affects carbon down to only 200-300mm max, so even farmed land can produce viable long-term carbon if managed according to an approved and regularly audited and verified Carbon Management Strategy.

Grasslands and preferred grazing practices on the other hand do have proven biodiversity benefits, especially when combined with tree planting. Such practices will actively engage farmers in biological enhancement and improved valuations of their farms, reducing the perceived commercial imperative to continue to clear trees as has been happening.

Please note, I am not I am advocating actively farmed land as biodiversity enhancing, although it does improve water and run off characteristics, (however, regenerative grazing practices certainly are), but it can be part of a carbon management process and be used alongside other biodiversity enhancing strategies as part of an integrated farm biodiversity management plan to deliver net biodiversity outcomes.

This year, the first formal Government Agency Issued Australian Carbon Credit units or ACCUs, have been awarded to a soil carbon farming project. The fact that ACCUs are now being issued under a Federal Government approved Soil Carbon Methodology is testament to the fact that soil carbon can be enhanced, and robust carbon certificates issued in parallel with agricultural practices. This is boon to farmers and as part of an integrated strategy, means farmers can now be paid for not clearing land and gain extra benefits from farming creating additional stability for farm incomes and food security for Australia. Two possible approaches that can used are summarized as follows:

–    transient soil carbon is weighted down and dealt with only as a long-term average with up to 60% of the good season gains discounted to allow for long term averages that include drought;

–    long term (100 year plus carbon) is enhanced/engineered in the various ways mentioned above, measured and treated at full value based on ongoing measurement and an approved plan.

Because both approaches are subject to ongoing measurement and verification for the first 25 years, the carbon drawdown benefits are considered reliable.

So, coming back to the building sector, until I learnt about the issuance of soil farming ACCUs and the rest of the above, I had ruled out soil carbon farming from our impending NaturePositive+ Declaration Standard and have since reviewed that position.

Within the context of the Green Building Council of Australia and Property Council both promoting Nature-based carbon offset solutions to further net-zero outcomes in the property sector, biodiversity led carbon offsets are set to take the lead in the building sector going carbon net-neutral or indeed net-positive. Likewise, the impending Federal Government’s Nature Repair Market Bill, currently under Senate review having being passed by the Lower House in March 2023 and the attendant Biodiversity Certificates that will utilise the ACCU processes, are also set to reinforce this emerging new direction.

By adding soil carbon initiatives to the possible stable of NaturePositive⁺ options within our new standard, it means that all manufacturers that make or sell products in Australia, have the potential to be both recognised for their efforts and support farmers and their encompassed ecosystems, as well as supporting and adding resilience and social license to the building sector’s push towards net-zero and nature-positive outcomes.

David Baggs is CEO of Global Green Tag International Pty Ltd

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