You can never have enough information about Earth Repair/Ecosystem Restoration tools, techniques, and strategies. As most of you know, a couple among the many in use are green manuring and cover cropping.

Over the past year of my really digging into this topic I’ve come across a number of useful links to downloadable PDFs that allow for easy access and use.

One of the more intriguing finds was a book I found first published in the late 1920s that’s all about green manuring. It’s available for free as a 267-page PDF titled "Green Manuring: Principles & Practice" by Adrian J. Pieters, PhD (1927) – scanned and made available in 2006.

Another great reference is a 16-page PDF from ATTRA (Apropriate Technology Transfer for Rural Areas) titled "Overview of Cover Crops and Green Manures".

Here’s another published by Michigan State University, discussing cover cropping and green manuring in Michigan sustainable agriculture investigative studies – titled Cover Crop Choices for Michigan.

Lastly, check out these link to PDFs on the subject from a UK-based organization called HDRA – here and here.

Happy green manuring!

Editor’s note: Okay, now it’s your turn to share your best resources! Send them to editor (at) permaculture.org.au (if you want, we’ll even pay you to do it!) Also, if you have other green manure resources, please add them via the comment field below.

Map of fires in Russia

As I type, half of Russia is on fire after its hottest summer on record, Pakistan is dealing with the biggest floods in living memory and Australia is still in the clutches of a decade long drought. The last decade, worldwide, was the hottest since records began, and 2010 may break the records of 1998 and 2005 to become the hottest year we’ve ever known. We could spend weeks just examining the extreme weather events going on on a country by country basis.

Today we are crossing thresholds in our destruction of nature that will make all our subsequent efforts at earth healing even harder than they ever should have been. We have removed eco-systems, and their services, to such an extent that dangerous feedback loops are in progress. Climate is fast becoming a runaway train – and we’re its passengers.

Consider the fires in Russia, for example – millions of rain-producing trees are going up in smoke, taking their carbon with it. Trees growing in the ground are a carbon sink. On fire, they’re a carbon source. The Pakistan floods kill trees and plants likewise. These will later dry out and much of it too will end up in the atmosphere. With less trees in place, flooding events will occur even more often, and the soils these plants held in place will be washed away. The arctic permafrost is melting, releasing the powerful heat trapping gas, methane, at unprecedented levels – promising even more temperature increases. Our oceans are acidifying, threatening to turn the world’s largest carbon sink into a carbon source. And so on….

The dominoes are falling. It’s like nature is shouting to us: "If you don’t appreciate the services of these systems, then I’ll remove them all entirely".

We are facing crises on an unprecedented scale. Atop the foundations of an energy crisis, a climate crisis and a soil, water and biodiversity crisis, rests that mother of all crises – a food crisis. Crops are going up in smoke or are being washed away in deluges, our precious soils with them, while world grain stores are at their lowest levels and production is in decline whilst demand is rising. Such a food crisis, in the context of today’s population levels, translates, in turn, to a social/political/economic crisis on a scale that will make the convulsions of WWII look like a walk in the park.

It’s getting ugly, yet many are still not even awake to the perfect storm that is upon us. And of the few who are, many are discussing light bulbs and hybrids, cap and trade and recycling. They’re discussing being a little ‘less bad’, not recognising the urgent need for us – all 6.8 billion of us (and counting, at a rate of 1 billion every twelve years…) – to immediately become a positive element within our biosphere. And we must move fast! (The proverb ‘a stitch in time saves nine’ really rings true when considering these feedback loops….)

There is a solution though! That being a widespread, collaborative effort to assist nature in restoring, at scale, the biological processes that have, until today, kept this world stable for millennia. The solutions are in design, and in the observation and replication of natural symbiotic systems. We don’t need just less cars, we need more biology – more photosynthesis and more life! We might not be able to have rainforests everywhere, but we can certainly have food forests everywhere! The video clips below share a glimmer of hope along these lines. It documents an incredible journey of restorative transition for a 35,000 square kilometre area in the Leoss Plateau in the north of China. It is a journey that begins with completely eroded, overgrazed land where floods were a constant nightmare, and ends in terraced green hills, flood and food stability and prosperity. And, it only took ten years.

Give it a watch, and, as you do, consider what kind of social/political/economic systems would be the most conducive to achieving similar results in other places worldwide. It’s an interesting mix of top-down ‘interference’ (both in terms of blanket regulations and financial investment) combined with land ‘privatisation’, and participatory involvement at all levels. It reinforces for me the need to build resilient, localised, holistically educated and politically engaged communities whose members don’t discard government, but who through greater involvement in the decision-making process (including choosing their representatives) effectively become government and self-determine to build a world based on land stewardship and voluntary simplicity. We cannot act as individuals alone, working in our own self-interest, and achieve the kind of results you’ll see in the video below. We need to work collaboratively, and sometimes sensible, holistically discussed decisions will need to be enforced on individuals who either can’t see the big picture, or who don’t care.

Further reading:

• The Development of Farmer Managed Natural Regeneration
• The World’s Largest Water Harvesting Earthworks Project
• The Biology of Global Warming

Over the past couple of years, there has been quite a bit of attention paid to the purchase of massive amounts of agricultural land by rich countries and corporate entities in the developing world. Craig Mackintosh wrote about this on this site, as have many other very informative reports and press stories.

To summarize, there has been approximately US$100 Billion mobilized to purchase somewhere between 40 – 50 million hectares (roughly 100 – 125 million acres) of agricultural land worldwide.

Quoting a recent article published by The Financial Times on July 27, 2010, World Bank warns about the ‘farmland grab’ trend:

Investors in farmland are targeting countries with weak laws, buying arable land on the cheap and failing to deliver on promises of jobs and investments, according to the draft of a report by the World Bank.

“Investor interest is focused on countries with weak land governance,” the draft said. Although deals promised jobs and infrastructure, “investors failed to follow through on their investments plans, in some cases after inflicting serious damage on the local resource base”.

In addition, “the level of formal payments required was low”, making speculation a key motive for purchases. “Payments for land are often waived … and large investors often pay lower taxes than smallholders … or none at all.”

[A World Bank study entitled] ‘The Global Land Rush: Can it yield sustainable and equitable benefits?’ is the broadest study yet of the so-called “farmland grab”, in which countries invest in overseas land to boost their food security, or investors – who are mostly locals – buy arable land. The “farmland grab” trend gained notoriety after an attempt in 2008 by South Korea’s Daewoo Logistics to secure a large chunk of land in Madagascar for a very low price and vague promises of investment. The deal contributed to a coup d’état in the African country." – farmlandgrab.org

A couple of excellent examinations of this issue has been published by The Oakland Institute. They are:

• (Mis)Investment in Agriculture: The Role of the International Finance Corporation in the Global Land Grab
• The Great Land Grab: Rush for World’s Farmland Threatens Food Security for the Poor

This topic has also been featured by news outlets such as Al-Jazeera English’s Riz Khan Program "Land Grab or Investment":

Part I

Part II

What is, in essence, the primary driver behind these land deals is identified in a UK Telegraph article titled ‘Britain facing food crisis as world’s soil ‘vanishes in 60 years’, which was published on February 3, 2010. Quoting from the article, which followed the Carbon Farming conference that took place in Borenore, NSW Australia November 2009:

An estimated 75 billion tonnes of soil is lost annually with more than 80 per cent of the world’s farming land "moderately or severely eroded", the Carbon Farming conference heard.

A University of Sydney study, presented to the conference, found soil is being lost in China 57 times faster than it can be replaced through natural processes.

In Europe that figure is 17 times, in America 10 times while five times as much soil is being lost in Australia.

Soil is also a valuable store of carbon and can release the greenhouse gas if it is ploughed or dug up.

The conference heard world soil, including European and British soils, could vanish within about 60 years if drastic action was not taken.

This will lead to a global food crisis, chronic food shortages and higher prices, the conference heard.

Despite better than average farming practices, European soil might last for 100 years if no further damage occurs worldwide, scientists said.

In reality, however, increased land pressures aimed at compensating global production losses would likely mean it will run out faster, they added. – telegraph.co.uk

The issues connected to the Global Land Grab controversy are directly linked to those of the global Earth Repair/Ecosystem Restoration Work (ERW) agenda. ERW has yet to be seriously discussed as means by which the global ecological dilemma and degrading of natural capital can be effectively addressed.

The attempts made to purchase these vast amounts of arable land speaks to the manner in which investors treat natural capital like financial capital. The impression given is that the ecological problem is something that can be avoided by buying our collective way out of the situation. The rich and wealthy are mostly woefully ignorant of how to manage & use natural capital. This is where those acquainted with ERW techniques and strategies can provide an indispensable service.

I was invited to speak at a socially responsible/triple bottom line investors conference taking place in London November 2010. The event is being put on by TBLI (Triple Bottom Line Investment). I intend on addressing this very issue in my presentation entitled: "Economic Support for Global Earth Repair Work and Ecological Restoration – Making The Case".

Used for centuries in Eastern Europe and Germany, hugelkultur (in German hugelkultur translates roughly as “mound culture”) is a gardening and farming technique whereby woody debris (fallen branches and/or logs) are used as a resource.

Often employed in permaculture systems, hugelkultur allows gardeners and farmers to mimic the nutrient cycling found in a natural woodland to realize several benefits. Woody debris (and other detritus) that falls to the forest floor can readily become sponge like, soaking up rainfall and releasing it slowly into the surrounding soil, thus making this moisture available to nearby plants.

Hugelkultur garden beds (and hugelkultur ditches and swales) using the same principle to:

• Help retain moisture on site
• Build soil fertility
• Improve drainage
• Use woody debris that is unsuitable for other use

Applicable on a variety of sites, hugelkultur is particularly well suited for areas that present a challenge to gardeners. Urban lots with compacted soils, areas with poor drainage, limited moisture, etc., can be significantly improved using a hugelkultur technique, as hugelkultur beds are, essentially, large, layered compost piles covered with a growing medium into which a garden is planted.

Creating a hugelkultur garden bed is a relatively simple process:

1. Select an area with approximately these dimensions: 6 feet by 3 feet
2. Gather materials for the project:

• Fallen logs, branches, twigs, fallen leaves (the “under utilized” biomass from the site). Avoid using cedar, walnut or other tree species deemed allelopathic.
• Nitrogen rich material (manure or kitchen waste work well and will help to maintain a proper carbon to nitrogen ratio in the decomposing mass within the hugelkulter bed).
• Top soil (enough to cover the other layers of the bed with a depth of 1 – 2”) and some mulching material (straw works well).

3. Lay the logs (the largest of the biomass debris) down as the first layer of the hugelkulter bed. Next, add a layer of branches, then a layer of small sticks and twigs. Hugelkultur beds work best when they are roughly 3 feet high (though this method is forgiving, and there is no fixed rule as to the size of the bed. That is where the “art” comes in!)
4. Water these layers well
5. Begin filling in spaces between the logs, twigs and branches with leaf litter and manure of kitchen scraps.
6. Finally, top off the bed with 1 – 2” of top soil and a layer of mulch.

The hugelkulter bed will benefit from “curing” a bit, so it is best to prepare the bed several months prior to planting time (prepare the bed in the fall for a spring planting, for example, in temperate northern climates), but hugelkultur beds can be planted immediately. Plant seeds or transplants into the hugelkulter bed as you would any other garden bed. Happy hugelkulturing!

One of the most transformative experiences in my life was from studying soil science many years ago. Getting something of an understanding of the inner workings of that thin skin which covers our earth created thought-connections in my mind that had me looking at the world in a profoundly new way.

Amongst the many things I realised and gained appreciation for was the myriad mechanisms in natural systems that, in concert with each other, provided incredible stability and harmony. I recognised that if only many more people would come to study and learn genuine, holistic, biological soil science (rather than the reductionist chemistry- and product-focussed ’science’ encouraged in universities today by industry) we are actually well able to mimic these systems to bring the same harmony into our own fields, and thus retain resilience whilst still providing for our needs. We could give back to the soil as much as we take. Indeed, we could even reverse our current soil inventory deficit by building soil.

I learned that the carbon cycle was a, or the, critical element. Contrary to popular belief, water soluble nitrogen applications actually depletes soil carbon, rather than builds it – because soil micro-organisms, if I am to use simplistic terminology, feed on nitrogen, and excess soluble supplies send them into a frenzy of activity. That activity is focussed on breaking down organic matter (carbon rich humus). Regular dousings of water-soluble nitrogen fertiliser (and yes, that also includes concentrated chicken litter and blood meal) turns our microscopic soil buddies into hyperactive, and short lived, soil baddies. The same thing occurs with over-aeration of soil from ploughing and other manipulations. The result is rapid plant growth, but at the expense of plant health – and, significantly, resulting in our effectively burning up the organic matter content in our soils, without which there can be no life on this earth.

I learned these things a decade and a half ago, and from reading books decades older, and yet today we still find articles titled ‘New research: synthetic nitrogen destroys soil carbon, undermines soil health‘.

The case for synthetic N as a climate stabilizer goes like this. Dousing farm fields with synthetic nitrogen makes plants grow bigger and faster. As plants grow, they pull carbon dioxide from the air. Some of the plant is harvested as crop, but the rest—the residue—stays in the field and ultimately becomes soil. In this way, some of the carbon gobbled up by those N-enhanced plants stays in the ground and out of the atmosphere.

Well, that logic has come under fierce challenge from a team of University of Illinois researchers led by professors Richard Mulvaney, Saeed Khan, and Tim Ellsworth. In two recent papers (see here and here) the trio argues that the net effect of synthetic nitrogen use is to reduce soil’s organic matter content. Why? Because, they posit, nitrogen fertilizer stimulates soil microbes, which feast on organic matter. Over time, the impact of this enhanced microbial appetite outweighs the benefits of more crop residues.

And their analysis gets more alarming…. – Grist (emphasis ours)

This is an excellent article that I’d recommend all to read and absorb. But, the worrying aspect is that we’re calling it ‘new research‘. The things I learned years ago have been known for decades, something the article above expresses also – quoting from renowned organic pioneer, Sir Albert Howard, from the 1940s – but in a competition- and product-oriented world it has not been a popular concept, because widespread uptake and implementation of this knowledge would make most agricultural products not only redundant, but they’d also be seen as an enemy to sustainable, and healthy, human existence.

The ’self-interest’ basis of our western ‘invisible structures’ (economics, politics, etc.) is the foundational motivation that ensures extraction today with little thought for tomorrow. We create a perception of need, by creating problems that don’t, or shouldn’t, exist – so we can simultaneously create saleable ’solutions’ for them. The self-interest, economy-must-grow mindset thus either consistently ignores or, as is the case here, actively obscures important ecological truths.

How many times will we ‘discover’ these facts? How many times must we re-invent the wheel? As long as profits are the basis of our society, and private interests the controlling powers, then this information will never reach momentum. Why? Because when schools operate for the public good, unbiased, non-commercialised research can be undertaken with taxpayer dollars. When private interests reign, and schools operate without government support, then schools either close, or get funded by BigAgri.

While it’s clear that funding cash is the carrot used by agribusiness to entice researchers into asking the questions industry is most interested in having answered, there is a stick involved: corporately held patents used to block them from asking others. – Monsanto U: Agribusiness’s Takeover of Public Schools

It should be no surprise that the privatisation of our schooling systems worldwide has helped BigAgri propagandise the next generation and has leveraged their control of the world’s food systems.

Nitrogen, Phosphorus, and Potassium on the Menu. Courtesy: Marc Roberts

As our soils continue to degrade through the use of Big Agri’s ‘products’, I see an explosion of social and environmental disasters coming to pass. Amongst all the obvious issues, there will also be an ever-increasing public health disaster as the nutrient density of the ‘food’ grown on ever-more-inert, ever-more-lifeless, soils continues to diminish.

We often call this an agricultural treadmill. Our use of nitrogen depletes soils, creating the need for more nitrogen applications. The resulting unbalanced, nutrient-starved plants attract legions of insects, resulting in the need for increasing pesticide applications. The land’s natural effort to restore balance causes soil-restoring plants to spring up (some call them ‘weeds’), inspiring farmers to douse their land with herbicides. In both cases we’re effectively pouring poison on our own food. That’s not smart – but we’ve somehow come to regard it as normal.

Things progressively deteriorate in a downward spiral, but instead of solving the root issue we instead move to genetic engineering to try to patch things up.

Now, you probably assume the ‘root issue’ I’m talking about is our lack of understanding of soil science. And, you’d be right. But perhaps even deeper is the root issue of the kind of economics we base our society on – the kind of economics whose existence relies on obscuring the truth, to preserve and grow a customer base. This entire agricultural treadmill is caused by ’self-interest’ perpetually expressing itself in creating desire and/or need for products that should not exist, and the genetic tinkering of plant genes is an effort to see if we can’t get nature to adapt to the economic framework we’ve built, rather than discover and build a social framework that can work harmoniously with her unchangeable laws.

Using the term treadmill is arguably increasingly inappropriate too, as it leads people to think it can continue ad infinitum. The reality is we’re now watching it collapse. Just as we’ve all but completely exhausted our soils with the fossil fuel based Green Revolution, we’re also at, or fast approaching, peak oil.

Let’s stop calling this ‘new research’. This knowledge needs to saturate and become ‘established fact’ in our school systems, and our school systems need to fulfil the needs of society, not private interests, to help transition us to a world where we recognise our place in the carbon cycle, amongst all the other interdependent elements within the biosphere.

The Dark Side of Synthetic Nitrogen Fertilizers

~~~~~~~~~~

P.S. If you can’t wait for a widespread transformation in our mainstream educational institutions (I’m turning blue as I hold my breath), and want to understand more about soil science now – then I’d really encourage you to take Paul Taylor’s excellent five-day course on the topic. At time of writing, his next course begins September 20, 2010. Keep an eye on our course listings for other dates.

This video can be downloaded in high resolution from Vimeo (see ‘About this video’ section on lower right side’).

I hope you’ll enjoy this clip. More, I hope it encourages you to dare to be different, and dare to have your work noticed. The garden we profile in the video above, as you’ll discover after watching it, has just won a national competition held by the Jordanian Department of Education – for schools who incorporate environmental projects into their curriculum. This means that thousands of schools, in what is arguably the most water-stressed country on the planet, now have the possibility to learn from this humble example of permaculture in action – and get inspired to do similar.

Special thanks to Lesley Byrne for her enthusiastic support, and to Nadia Lawton for her vision and determination to help her own people – and in so doing setting such an excellent example for us all.

by Christine Jones, PhD

The number of farmers in Australia has fallen 30 per cent in the last 20 years, with more than 10,000 farming families leaving the agricultural sector in the last five years alone. This decline is ongoing. There is also a reluctance on the part of young people to return to the land, indicative of the poor image and low income-earning potential of current farming practices.

Agricultural debt in Australia has increased from just over $10 billion in 1994 to close to $60 billion in 2009 (Fig.1). The increased debt is not linked to interest rates, which have generally declined over the same period (Burgess 2010).

Fig. 1. Increase in agricultural debt (AUD millions)
1994-2009 vs interest rates (%pa)

The financial viability of the agricultural sector, as well as the health and social wellbeing of individuals, families and businesses in both rural and urban communities, is inexorably linked to the functioning of the land.

There is widespread agreement that the integrity and function of soils, vegetation and waterways in many parts of the Australian landscape have become seriously impaired, resulting in reduced resilience in the face of increasingly challenging climate variability.

Agriculture is the sector most strongly impacted by these changes. It is also the sector with the greatest potential for fundamental redesign.

The most meaningful indicator for the health of the land, and the long-term wealth of a nation, is whether soil is being formed or lost. If soil is being lost, so too is the economic and ecological foundation on which production and conservation are based.

The soil carbon sink

In July 2009, the Portuguese government introduced an AUD$13.8 million soil carbon offsets scheme based on dryland pasture improvement, compliant with Article 3.4 of the Kyoto Protocol.

The scheme will pay an estimated 400 participating farmers to establish biodiverse perennial mixed grass/legume pastures (upwards of 20 species) to improve soil carbon, soil water holding capacity and livestock productivity in an area of approximately 42,000 hectares (Watson, 2010).

The Portuguese scheme has been designed to comply with Kyoto’s strict criteria of additionality and permanence. Coordinator of Project Extensity and Terraprima project leader, Professor Tiago Domingos, has calculated that the area of agricultural land in Portugal amenable to soil carbon offsets could collectively sequester more than the current Portuguese national emissions deficit under existing Kyoto arrangements (Watson 2010).

The mediterranean-type climate of central and southern Portugal is very similar to that in many parts of south-eastern, southern and south-western Australia. The Portuguese Terraprima data illustrated in Fig.2 show that under sown perennial pasture, soil organic matter increased to a level of 3% over 10 years, from a starting point of 0.87%.

Fig. 2. Accumulation of soil organic matter (SOM), shown as percentage
by weight, in soils under three pasture types:
SG = sown perennial pasture;
FNG = fertilised annual pasture;
NG = unfertilised annual pasture
(from Watson 2010).

The Portuguese soil carbon offsets project aims to sequester 0.91 million tonnes of CO2 from 2010 to 2012 (Watson 2010). This equates to the sequestration of 10.85t CO2/ha/yr.

In addition to the carbon payments they receive, participating Portuguese farmers are reported as “enjoying the environmental spin-offs of greater biodiversity, higher soil fertility, higher water infiltration rates, less erosion, less desertification, fewer fires, less floods, improvement in water quality, less dependence on concentrated feed for their herds in protracted dry periods and better milk and meat quality” (Watson 2010).

US study on soil carbon sequestration rates under perennial grassland

Recent research by United States Department of Agriculture (Liebig et al. 2008) investigated soil carbon sequestration under a perennial native grass, switchgrass (Panicum virgatum) grown for the production of cellulosic ethanol.

Despite the annual removal of aboveground biomass, low to medium rainfall and a relatively short growing season, the USDA-ARS research, averaged across 10 sites, recorded average soil carbon sequestration rates of 4t CO2/ha/yr in the 0-30 cm soil profile and 10.6t CO2/ha/yr in the 0-120 cm profile (Liebig et al 2008).

The best performing site was at Bristol, where soil carbon levels increased by 21.67 tonnes in the 0-30 cm soil profile over a 5 year period. A soil carbon increase of 21.67t C/ha equates to the sequestration of 80t CO2/ha.

At the three sites where carbon was measured to 120 cm, the USDA research found relatively high sequestration rates below 30 cm. The sequestration rate was higher for the 30-60 cm increment than for the 0-30 cm increment (18.2t CO2/ha vs 16.5t CO2/ha, respectively). A possible interpretation is that the deeper the sequestration, the greater the likelihood that the carbon be protected from oxidative and/or microbial decomposition.

There were virtually no ‘biomass inputs’ to soil in these trials, as all aboveground material was removed for ethanol production. This suggests the liquid carbon pathway (Jones 2008) as the primary mechanism for soil building.

Carbon trading in the real world

The recent demise of the Federal Government’s proposed Carbon Pollution Reduction Scheme provides an opportunity to reflect on the true meaning of a carbon-based economy.

For some time, analysts have tipped carbon to become the world’s most traded commodity. The reality is that it has been the world’s most traded commodity for millennia.

A great variety of life forms require liquid carbon – referred to in the scientific literature as ‘dissolved organic carbon’ (DOC) – for their growth and reproduction. The growth of trees, crops and pastures, for example, requires the transport of dissolved carbon via sap within the plant; animal growth is dependant on the digestion of carbon containing foods and the transport of dissolved carbon to cells via the blood; the formation of topsoil is dependent on photosynthesis and the transport of dissolved carbon, via a microbial bridge, from plants to soil.

Carbon is the currency for most transactions within and between living things. Nowhere is this more evident than in the soil. Here, carbon is king. Mycorrhizal fungi, which are totally dependant on dissolved organic carbon from green plants, trade carbon with colonies of bacteria located at their hyphal tips in exchange for macro-nutrients such as phosphorus, organic nitrogen and calcium, trace elements such as zinc, boron and copper, and plant growth stimulating substances (Killham 1994, Leake et al. 2004).

By means of an extraordinary physiological process known as ‘bidirectional flow’ nutrients are transported to roots at the same time as dissolved organic carbon moves through fungal hyphae in the opposite direction (Killham 1994, Leake et al. 2004). Indeed, mycorrhizal roots are significant sinks for carbon, transferring as much as 15 times more carbon to soil as adjacent non-mycorrhizal roots (Killham 1994).

Impoverishment of agricultural soils

Mycorrhizal fungi and associative bacteria are very strongly inhibited by excessive soil disturbance and the high levels of water-soluble phosphorus and nitrogen commonly used in modern agriculture (Killham 1994, Leake et al. 2004). Where soils have been subjected to cultivation and/or the application of MAP, DAP, superphosphate, urea or anhydrous ammonia, the suppressed mycorrhizal colonisation of plant roots significantly reduces carbon flow. The structural degradation of agricultural soils, accompanied by mineral depletion in food, has largely been the result of the inhibition of this natural carbon pathway.

When carbon supply is limited by the loss of the primary pathway for sequestration, the physical, chemical and biological functions normally performed by healthy soil are markedly reduced.

Historical levels of soil carbon

Noted Polish explorer and geologist, Sir Paul Edmund [Count] Strzelecki, travelled widely through the colonies of south-eastern Australia during the period 1839 to 1843, collecting minerals, visiting farms and analysing soils. One of the questions Strzelecki posed was, what factors determine soil productivity? He collected 41 soil samples from farmed paddocks of either high or low productivity. The analyses revealed that the most important determinant of soil productivity was the level of soil carbon (measured as organic matter in Strzelecki’s day).

Of the 41 samples analysed, Strzelecki (1845) found …

The top 10 soils in the high productivity group had organic matter levels ranging from 11% to 37.75% (average 20%). The lowest ranking 10 soils in the low productivity group had organic matter levels ranging from 2.2% to 5.0% (average 3.72%)

The soils with the highest organic matter levels also had the highest moisture holding capacity, with an 18-fold difference in capacity to hold moisture between the lowest and the highest (Strzelecki 1845).

Strzelecki’s data indicate that organic matter levels in the early settlement period were around five to ten times higher than in many soils today. The soil test data from Strzelecki is consistent with the writings of first settlers, who described soils in the early settlement period as soft, spongy and absorbent. The 1840s journal of George Augustus Robinson, for example, contains numerous references to the extremely fertile and productive soils encountered by pastoralists in the mid-1800s (Presland 1970).

Soil carbon and soil moisture

In addition to enhancing nutrient availability, carbon performs many other functions in soil, including the maintenance of soil porosity, aeration and water-holding capacity.

Glenn Morris (Morris 2004) extensively researched the water holding capacity of humus (an extremely stable form of soil carbon) and concluded that within the soil matrix, one part of soil humus could, on average, retain a minimum of four parts of soil water.

From this relationship it can be calculated that an increase of 16.8 litres (almost two buckets) of extra plant available water could be stored per square metre in the top 30 cm (12”) of soil with a bulk density of 1.4 g/cm3, for every 1% increase (in absolute terms) in the level of soil organic carbon. This equates to 168,000 litres of water that could be stored per hectare, in addition to the water-holding capacity of the soil itself (Jones 2006).

The flip side is that the same amount of water-holding capacity will be lost when soil carbon levels fall. Low soil moisture and low levels of soil organic carbon go hand in hand.

Soil organic carbon levels in many areas have fallen by at least 3% (in absolute terms) since the time of European settlement, This reduction in soil carbon content represents the LOSS of the ability of soil to store around 504,000 litres of water per hectare.

Mycorrhizas and water

It is well known that mycorrhizal fungi access and transport nutrients in exchange for carbon from the host plant (Killham 1994, Leake et al. 2004). What is less well known is that in seasonally dry, variable, or unpredictable environments (that is, most of Australia), mycorrhizal fungi play an extremely important role in plant-water dynamics.

Mycorrhizal fungi can supply moisture to plants in dry environments by exploring micropores not accessible to plant roots. They can also improve hydraulic conductivity by bridging macropores in dry soils of low water-holding capacity (such as sands). In these situations, external wicking along the hyphae is of greater importance than cytoplasmic flow (Allen 2007). Mycorrhizal fungi can also increase drought resistance by stimulating an increase in the number and depth of plant roots.

Soil carbon and soil nitrogen

Aside from water, nitrogen is frequently the most limiting factor to crop and pasture production. It is one of the great ironies of agriculture that the atmosphere is around 78% nitrogen, but not one single molecule is directly available to plants. There are approximately 78,000 tonnes of nitrogen gas sitting above every hectare of land. Apart from small accessions via lightning, this nitrogen cannot be accessed without a microbial bridge.

Nitrogen-fixing bacteria – be they free-living in the rhizosphere, confined to nodules on plant roots, or existing as endophytes in leaves or stems – derive most of their energy from liquid carbon fixed during photosynthesis.

Adding water-soluble nitrogen in the form of urea, anhydrous ammonia or nitrate destabilises the plant-soil ecosystem by reducing the activity of mycorrhizal fungi and free living N-fixing bacteria (Killham 1994). The presence of high levels of water-soluble nitrogen in soil sends a signal to plants to reduce the supply of liquid carbon to microbial symbionts, effectively inhibiting the microbial associations that would otherwise supply atmospheric nitrogen for free.

This contradicts the widely promoted belief that nitrogenous fertiliser needs to be added in order for stable soil carbon to form. Indeed, the opposite is true (Khan et al. 2007, Larson 2007, Mulvaney et al. 2009).

Soil test data show that as soil carbon levels increase in microbially active soils, availabilities of P, K, S, Ca, Zn and B commonly increase, while levels of nitrate nitrogen are often reduced.

If plants are mycorrhizal, they don’t require nitrogen in a mineralised form, that is, in the form of nitrate or ammonium. In order to transport mineralised nitrogen, mycorrhizal fungi have to convert it to glutamate, which represents an energy cost. For this reason, nitrogen is preferentially transported in an organic form, generally as amino acids such as glycine and glutamine (Leake et al. 2004).

Utilisation of organic nitrogen by mycorrhizal fungi closes the nitrogen loop and prevents soil acidity, as well as preventing volatilisation of nitrogen to the atmosphere and leaching to aquifers, rivers and streams. Changes to soil chemistry and nitrogen dynamics in microbially balanced soils also reduce the abundance of ‘weedy’ species such as annual ryegrass, capeweed, mustard weed and thistles. The germination of these species is stimulated by the ready availability of nitrate nitrogen.

Soil as a methane sink

Wetlands, rivers, oceans, lakes, plants, decaying vegetation (especially in moist environments such as rainforests) – and a wide variety of creatures great and small – from termites to whales, have been producing methane for millions of years. The rumen, for example, evolved as an efficient way of digesting plant material around 90 million years ago.

Ruminants including buffalo, goats, wild sheep, camels, giraffes, reindeer, caribou, antelopes and bison existed in greater numbers prior to the Industrial Revolution than are present today.

There would have been an overwhelming accumulation of methane in the atmosphere had not sources and sinks been able to cancel each other over past millennia.

Although most methane is inactivated by the hydroxyl (OH) free radical in the atmosphere (Quirk 2010), another source of inactivation is oxidisation in biologically active soils. Aerobic soils are net sinks for methane, due to the presence of methanotrophic bacteria, which utilise methane as their sole energy source (Dunfield 2007). Methanotrophs have the opposite function to methanogens, which bind free hydrogen atoms to carbon to reduce acidosis in the rumen.

Recent research undertaken by Professor Mark Adams, Dean of the Faculty of Agriculture at Sydney University, found that one hectare of pasture land could oxidise as much methane as emitted by 162 head of cattle in an entire year (Cawood 2009). The highest methane oxidation rate recorded in soil to date has been 137mg/m2/day (Dunfield 2007) which, over one hectare, equates to the absorption of the methane produced by approximately 1000 head of cattle.

In Australia, it has been widely promoted that livestock are a significant contributor to atmospheric methane and that global methane levels are rising. However, there is no evidence to suggest that methane emissions from ruminant sources are increasing. Indeed, it would seem there has been no clear trend to changes in global methane levels, from any source, over recent decades.

The increase in global methane levels from 1930 to 1970 was due to emissions from the production, transmission and distribution of natural gas (Quirk 2010). There was a tenfold increase in the use of natural gas through the 1960s and 1970s. The source of many of the natural gas emissions, such as leakages from the Trans-Siberian pipeline, have since been rectified (Quirk 2010). Measurements over the last 25 years show concentrations of atmospheric methane are merely exhibiting natural variation, with no significant trends in any direction (Fig.3).

Fig. 3. Variations in annual changes in atmospheric methane concentrations
from 1983 to 2009, from Dlugokencky et al. (2009).
Measurements are in parts per billion per year.

There is therefore no scientific basis for selectively targeting ruminants for a ‘methane tax’, or worse, interfering with this natural process. Farming in ways that enhance, rather than inhibit, soil biological activity, would improve the capacity of agricultural soil to act as a methane sink, helping balance the greenhouse equation. The issue with today’s industrialised approach to agriculture is that methanotrophic bacteria are chemically sensitive. Their activities are reduced by nitrogenous fertilisers, herbicides, pesticides, acidification and excessive soil disturbance (Dunfield 2007).

Soil carbon and human health

The nutritional status of soils, plants, animals and people has fallen dramatically in the last 50 years, due to losses in soil carbon, the key driver for soil nutrient cycles. Soil health and human health are more deeply connected than many people realise. Food is often viewed in terms of quantity available, hence ‘food scarcity’ is not seen as an issue in Australia. However, food produced from depleted soils does not contain the essential trace minerals required for the effective functioning of our immune systems.

Routine premature deaths from degenerative conditions such as cardiovascular disease and cancer have become prominent when they were once relatively uncommon. The cancer rate, for example, has increased from approximately 1 in 100, fifty years ago, to almost 1 in 2 today. The effectiveness of the human immune system has been compromised by increased exposure to more and more chemicals coupled with insufficient mineral density in food.

The low nutritional status of many basic food items is highlighted in data from the UK Ministry of Health. Depletion in the level of minerals in vegetables for the period 1940-1991, for example, shows copper levels reduced by 76%, calcium by 46%, iron by 27%, magnesium by 24% and potassium by 16%. Deficiencies in plants translate through to deficiencies in animals. A piece of steak now contains only half the amount of iron that it would have contained 50 years ago.

Vitamin and mineral deficiencies in food indicate that the symbiotic relationship between plants and soil microbes, whereby minerals are exchanged for liquid carbon, has been disrupted.

The best national health policy would be a national soils policy. But we don’t have one.

Our hospitals are over-filled and our health system is struggling to cope with illnesses that are highly correlated to the lack of essential vitamins, minerals and trace elements in our diet. The availability of these nutrients is determined to a large extent by the integrity of the soil food-web and the microbe bridge, which in turn are dependent on active soil sequestration of dissolved organic carbon.

Food labelling and a ‘Soil Integrity Index’

Food choices can have very significant effects on the kind of food produced and how it is produced. Currently, it is not possible for consumers to choose foods high in minerals, grown on healthy soils, as there is no labelling for food quality.

It is proposed that a ‘Soil Integrity Index’ with index parameters of

1. level of microbial diversity
2. soil carbon content and
3. soil water holding capacity

be used as the basis for a food labelling system.

The labels would need to be simple, with perhaps a star system (as in one, two or three stars). If a food labelling mechanism was in place, Australia’s largely city-based population could use food choices to improve not only the health of their families, but also the function and resilience of agricultural soils, thereby actively participating and supporting biology friendly farming.

The future landscape

The challenge for the future prosperity of Australian agriculture is to convert soil from its current status as a net source of carbon, to a revitalised state as a net carbon sink.

Agricultural research tends to focus on conventionally managed crop and pasture lands where intensive use of agrochemicals has dramatically reduced the number and diversity of soil flora and fauna, including beneficial microbes such as mycorrhizal fungi. As a result, the potential contribution of microbial symbionts to agricultural productivity has been greatly underestimated (Allen 2007).

Building soil carbon does not require adding biomass to soil. While crop stubbles and mulch are important for protecting soil from wind and water erosion and buffering temperature extremes, their contribution to soil carbon is limited by eventual decomposition to CO2.

The first step to restoring soil function is ‘do no harm’. A simple change from high-analysis N and/or P fertilisers to biological products such as worm leachate (vermiliquid), compost extract, seaweed extract and/or fish emulsion, applied as a seed dressing and/or a post-emergent foliar spray, will support microbial diversity, increase plant photosynthetic rate, increase the flow of liquid carbon to soil and enhance humification.

As the soil chemistry adjusts and nitrogen is converted to an organic form (freely available to mycorrhizal fungi but not to annual weeds) the incidence of pests, weeds and diseases that are stimulated by low levels of microbial diversity and high rates of water soluble nitrogen, will decline. As a result, there will be less reliance on the use of pesticides and herbicides that reduce the ability of soil to act as a sink for carbon, nitrogen, methane and moisture.

Changing the face of agriculture

Since 1960, global food production has doubled. At the same time, the soil resource on which food production is based has become seriously degraded.

The impoverishment of agricultural soils through depleted levels of biological activity and reduced carbon flow poses a greater threat to human existence than climate change.

In many regions of Australia, the effects of lower than average rainfall over the past decade have been compounded by loss of soil resilience and reduced moisture-holding capacity (Fig.4).

Fig. 4. Cropping over an old fence-line clearly demonstrates the extent to
which soil has been depleted by conventional farming practices. Paddocks
on either side of the fence have a history of high nitrogenapplication
(Photo Richard May).

It has been calculated that in the next 50 years, the planet will need to produce as much food as it has in the entire history of humankind. The way we produce that food will require a radical departure from business as usual.

At the beginning of this paper it was noted that the level of agricultural debt in Australia had increased almost 6-fold over the last 15 years. The amount of money invested by the farming community on non-biological inputs increases every year. Many of these products inhibit microbial diversity, preventing natural carbon flow to soils. Cessation of carbon flow reduces soil integrity, the mineral density in food and human health. It also prevents the processes of humification and topsoil formation from operating to any significant extent. The end result is even greater expenditure on agrochemicals in attempts to control the pest, weed, disease and fertility problems’ that ensue.

The statement that small farmers need to ‘get big or get out’ overlooks the fact that profit is the difference between expenditure and income. In years to come we will perhaps wonder why it took so long to realise the futility of trying to grow crops in dysfunctional soils, relying solely on increasingly expensive synthetic inputs.

Economic development is only sustainable if it strengthens, rather than depletes, natural resources.

The soil’s ability to produce nutrient dense, high vitality food – which after all, is agriculture’s real purpose – depends on appropriate management. Enhancing the natural flow of carbon to soils will result in increased microbial diversity, improved nutrient cycles, enhanced soil water-holding capacity, greater resilience, improved catchment health – and a more satisfying, profitable future for farmers.

The longer we delay undertaking regenerative changes to land management based on biology friendly farming practices that rebuild carbon-rich soils, the more soil carbon and soil water will be lost, exposing an increasingly fragile agricultural sector to escalating production risks, rising input costs and vulnerability to climatic extremes.

Its time to move away from depletion-style, high emission, chemically based industrial agriculture and get serious about grass-roots biologically based alternatives.

The future of Australia depends on the future of our soil – and our willingness to look after it.

Rebuilding soil productivity via the restoration of natural carbon flow and the sequestration of stable soil carbon is the only means of saving agriculture’s bacon – and ensuring a future for human society as we know it.

Literature cited

• Allen, M.F (2007). ‘Mycorrhizal fungi: highways for water and nutrients in arid soils’. Soil Science Society of America, Vadose Zone Journal. Vol 6 (2) pp. 291-297. DOI:10.2136/vzj2006.0068.
• Burgess, N. (2010). Agricultural debt from 1994 to 2009. Sourced from Westpac Economics& Reserve Bank of Australia. nburgess@westpac.com.au
• Cawood, M. (2009). ETS lifeline: soils capable of absorbing cattle methane. The Land, 3 September 2009.
• Dlugokencky, E. J. et al. (2009). Observational constraints on recent increases in the atmospheric CH4 burden. Geophysical Research Letters. 36, L18803, DOI:10.1029/2009GL039780.
• Dunfield, P. F. (2007). The soil methane sink. In D.S. Reay, C.N. Hewitt, K.A Smith and J. Grace, eds. Greenhouse Gas Sinks. pp. 152-170. Wallingford UK.
• Jones, C. E. (2006). Carbon and catchments. National ‘Managing the Carbon Cycle’ Forum, Queanbeyan, NSW, 22-23 November 2006. http://www.amazingcarbon.com
• Jones, C.E. (2008). Liquid carbon pathway unrecognised. Australian Farm Journal, July 2008, pp. 15-17. http://www.amazingcarbon.com
• Khan, S.A, Mulvaney, R.L, Ellsworth, T.R. and Boast, C.W. (2007). The myth of nitrogen fertilization for soil carbon sequestration. Journal of Environmental Quality 36:1821-1832. DOI:10.2134/jeq2007.0099
• Killham, K. (1994). ‘Soil Ecology’. Cambridge University Press.
• Larson, D. L (2007). Study reveals that nitrogen fertilizers deplete soil organic carbon. University of Illinois news, October 29, 2007. http://www.aces.uiuc.edu/news/internal/preview.cfm?NID=4185
• Leake, J.R., Johnson, D., Donnelly, D.P., Muckle, G.E., Boddy, L. and Read, D.J. (2004). Networks of power and influence: the role of mycorrhizal mycelium in controlling plant communities and agroecosystem functioning. Canadian Journal of Botany, 82: 1016-1045. DOI:10.1139/B04-060
• Liebig, M.A, Schmer, M.R, Vogel, K.P. and Mitchell. R.B. (2008). Soil carbon storage by switchgrass grown for bioenergy. Bioenergy Research 1: 215-222. DOI:10.1007/s12155-008-9019-5
• Morris G. D. (2004). Sustaining national water supplies by understanding the dynamic capacity that humus has to increase soil water-holding capacity. Thesis submitted for Master of Sustainable Agriculture, University of Sydney, July 2004.
• Mulvaney, R.L, Khan S.A, and Ellsworth, T.R. (2009). Synthetic nitrogen fertilizers deplete soil nitrogen: a global dilemma for sustainable cereal production. Journal of Environmental Quality 38:2295-2314. DOI:10.2134/jeq2008.0527
• Quirk T. W. (2010). Twentieth century sources of methane in the atmosphere. Energy and Environment, 21(3), pp. 251-256.
• Strzelecki, Paul Edmund de, (1845). Physical description of New South Wales and Van Diemen’s Land: accompanied by a geological map, sections and diagrams, and figures of the organic remains / by P.E. de Strzelecki. Printed for Longman, Brown, Green, and Longmans, London. (Note: prior to 1851 the state of Victoria was part of the colony of New South Wales).
• Watson, L. (2010). Portugal gives green light to pasture carbon farming as a recognised offset. Australian Farm Journal, January 2010, pp. 44-47.

The podcast is well worth a listen. Click play below:

I love to see people joining the dots like this!

Should you be in the area, Terry and others will be speaking at a three-day conference in Brisbane, titled ‘Farmers – Heroes of our Future‘ from July 20-22. You can view the conference program here. Given it’s July 20th as I type, it may be too late to register and go along, but if you’re in the Brisbane area I’ll leave you to make your own enquiries if you’re interested. Sounds like it’d be a great event to attend.

It’s 2am. I’m sitting on a nice toilet in a nice hotel room in a nice little town in Africa. But I don’t feel very nice. Three weeks ago I arrived in the town of Musoma on the eastern shore of lake Victoria, Tanzania. It’s my second time here. It’s unusual to return to an old permaculture posting so it felt both strange and comforting to visit old friends. They had assumed I would return again as to them I was family and family never leaves for long. But I am mzungu, white man. And in the West, we never stay for long. But I had not been sick then.

I contracted diarrhea two days after arriving. Not crippling, but enough to make my trips to town short, consciously timed ones. Not bad enough to panic. Perhaps that is why three weeks later I’m sitting on the toilet once again at 2am in the morning. Only this time it’s a little more serious. I contracted malaria two days ago and had moved from the delirious, early stage effects of high fever to feeling just plain horrible. On top of that, I had unknowingly overdosed on a western folk remedy and have been violently vomiting for the past eight hours. My one small cause for relief was a by product of my tiny bathroom. I could release my bowels and vomit into the hand basin at exactly the same time. This I had adeptly managed several times this past evening although I over shot the bowl the first time. Must remember to tip the cleaning lady extra in the morning.

I was not unaccustomed to this kind of experience in my three years in Africa. Although I dare say my friends would not be envying my present situation; this particular African flavour….

GRA is a small non profit NGO based in California, USA. In their own words, they are “committed to building a better world – one based on ‘respect for nature, universal human rights, economic justice and a culture of peace’ as expressed in the words of the Earth Charter.” Yes, all NGOs sing a similar song, but I happen to know they are very serious about it. I’ve worked for them before.

About three years ago Geoff Lawton, one of the most respected leaders in the field, conducted a two-week PDC (Permaculture Design Certificate course) in a small fishing village at the mouth of the Mara river. Based on the success of this course, GRA decided to develop a full demonstration garden on a plot in the centre of the village. Geoff contacted me. I contacted GRA. I soon arrived for a three month posting to teach six separate groups and to set up the garden. This new concept was bigger, bolder and more challenging.

GRA had recently purchased two and a half acres of land, with the intention of feeding 70 orphan families in the local community, provide employment and an income stream. All within a sustainable permaculture framework.

Kinesi is a small fishing village on the eastern shores of Lake Victoria. Twice a year the great rains that deluge the Serengeti flood into the great mara river. Kinesi is on the mouth of that river. It takes 45 mins by boat to run from the large local town of Musoma to Kinesi. When the lake is flat, it is a beautific bargain at a little over US$1. When the wind howls across the lake from the east, you check your insurance policy and look nervously for a zip lock bag to cover your laptop.

In Australia, I’m a permaculture designer. In Africa, a permaculture ‘expert’. I love this country. I arrived four days prior to have a handover with the ‘expert’ from Zimbabwe. By the time he left, I had not set foot upon the site or even met my new team. Africa.

The site had been active for three months and the full time team of 12 had been busy. The hectare site had been a blank sheet of heavily compacted grazing land that sloped down to the big lake – some salt affected. The site had been swaled and planted out with a variety of legumes, perennial herbs and vegetables. While the region is in the wet/dry tropical region of central Africa, constituting two wet seasons, our plot had all the hallmarks of an arid design. With the wet season officially underway in less than a week, it was time to hustle.

As is typical in many denuded landscapes, a lower site has to handle a lot more water than that which falls upon it and this one was no exception. A week later we found out.

The first rain episode was a doozy. The lead berm blew out and took a lot of the bean crop with it. The salt exclusion drain worked very well and banana pits filled to the top and began slowly drowning the little suckers. In the next week we made rapid repairs to the wall, removed all the banana suckers from the swampy land at the bottom of the plot, and found a novel solution to release the pressure from the top trench.

Expanding upon the idea of a co-joined circle guild, we redesigned the blank eastern boundary to incorporate a descending array of pits. Acting as a spillway, we engineered the top swale to flow into possibly the largest flow form in Africa. 12 descending pits – each 2m x1.5m x1m deep – very effectively shed the water from heavy rain events sending it cleanly and rapidly into the lake. When the system is mature and infiltrating water more effectively, this can then be shut off and the pits filled with water hyacinth and used more conventionally.

While we were developing the garden, a separate team was constructing a compressed earth, sand and cement building at the top of the site. I observed one day that while the garden team was technically creating a facility to feed the orphans, it was the large structure at the top of the site that was drawing the lions share of the attention. Pondering this, I recalled some advice from a associate many years ago. He said “If you want to get respect in Africa, you have to create something big.” This had been my experience also.

Almost central to the plot was a slight depression that had remained very wet for the past month despite light rains. Of course with enough labour we could have created diversion drains, excluding the water. Or we could guide the water into an aquaculture pond.

While Furuno wrote eloquently of the ‘Power of duck’, little is mentioned of the power of hoe. In an amazingly short time, our hard working group excavated a pond 10 x 15 metres that, while lacking the dramatic presence of a excavator, gave the pond an individual presence and place that no machine could match, helped in no small part one joyous morning when the team instructed one the Mzungus (white man), Phillipe, to dance local style – the ensuing rapturous laughter echoing off the pond wall.

Three weeks later, a pond was completed with a capacity of 150m3, capable of producing approximately 300 mature tilapia every 3 months. Ducks will be incorporated into this system with a spillway on the up slope directing the nutrient rich water gently down the side of the pond to an on-contour wetlands area where taro and rice were planted. The overflow from the header tank will maintain a continuous supply of water to this system and if the windmill fails, the pond can be drained, the fish harvested and the pond used as an additional wetlands area to grow rice or tubers.

While we had 12 full time members, on Friday all the families of the orphan children came in and it was not unusual to have over 50 members digging, harvesting, laughing and singing. With the first harvest of Chinese cabbage came the first departure of mounds of green piled upon heads and bicycles. And great celebration.

Three months can go by very quickly in Africa. And in the tradition of grand farewells and cultural exchanges, the final day on site was a morning of firsts – my first time cooking breakfast for 45 people, and for the team, their very first pancake.

So where next? GRA’s intention is to use the site as a base and from here to spread the knowledge and benefits of Permaculture out into the community and then to greater Tanzania. Now with a strong and successful structure within the fence, the group is now establishing permaculture gardens in the local community using the experience and guidance of Julious Spiti, a consultant from Zimbabwe.

GRA has also just released a documentary on this project. Click here for an inspiring peek at this unique project and inspirational group.

Thanks to Darren Doherty for the head’s up on this new draft document from the Soil Carbon Coalition on measuring changes in soil carbon levels – the key indicator of soil health and fertility.

As we all (should) know well, land use changes over the last several centuries have significantly increased atmospheric CO2 levels. Soil mismanagement, which has increased in tandem with our burgeoning human population, has released mammoth amounts of carbon from the soil, where it is a positive, into the atmosphere, where it becomes, in its present excessive levels, a negative instead. Correct soil management, in contrast, can play a significant role in reversing that trend by pulling excess atmospheric CO2 out of the sky, through photosynthesis, and returning it to the soil in humus, the stable, final state of decomposition of organic matter – thus transforming excess CO2 from being a pollutant into a rich habitat for the micro- and macro-organisms that are the foundation of all life on this planet. Permaculture, through its favouring small scale, low-to-no till polycultures, and where the soil is always protected by a ’skin’ of plant or mulch cover, and maintained by appropriate naturally harvested moisture levels, is a powerful system for restoring the Gaia state of carbon balance.

If you’re building humus/carbon levels in your soil, you’re building fertility and health. More, you’re a hero – setting an example that if all were to follow, would rapidly put this planet back onto a sustainable path.

For those interested to more accurately gauge the effectiveness of their soil management, the document linked to here may prove entirely useful.

It is intended as a guide for do-it-yourselfers as well as part of the operating method for the Soil Carbon Challenge. It is also the first guide that attempts to understand and accommodate the variety of purposes or objectives people have in measuring soil carbon. Up to now, soil carbon measurement has been treated almost exclusively as a technical issue. But the main sources of risk and uncertainty in achieving the objectives are social, having to do with beliefs and attitudes.

Based on published literature and experience, this method outlines how to establish fixed plots, take samples, get them analyzed with the dry combustion method, and make calculations from the results.

Though targeted primarily at those who want to show possibility, and get feedback for their management, the guide should be helpful for those who wish to quantify carbon tonnage for "offsets" or research projects as well. How and what you measure, as well as the sources of uncertainty, depend on your purpose.

Measuring carbon change means establishing and measuring baseline plots, and then remeasuring them after 3 years or so. – Soil Carbon Coalition