Ichsani Wheeler [ TEDx Dubbo ] Good morning everyone, my name is Ichsani. I’m here to tell you a story about carbon. It is a substance that gets referred to very often. I think you’ll hear a lot more about it today. But we’ll start the story with something that doesn’t quite look like soil, that I want you to have a think about what it might be.

Now, if someone were to tell you that there was a group is entirely natural, entirely organic substances that, if we manage them carefully, could provide sustainable water and good food — from a healthy diverse environment –and provide some carbon offsets, as well as providing necessary ecosystem services, would you believe them? I know soil is not very glamorous and it changes very slowly, in the background, below ground, and people don’t really think a great deal about it, but it is incredibly important.

It doesn’t particularly do anything dramatic enough to make the news, except for the occasional dust storm or an occasional mudslide. Soil is periphery. It is in the background. It is everywhere and it is nowhere. It is rarely going to be in a rush to meet you, unless you happen to fall over.

But this beautiful, wonderful, diverse substance — with its living integration at the top there, underpins all life you can see on land.

The diversity in this top layer up there is so great that one shovel full contains more living organisms than all the humans who ever lived on the planet. There’s so much we have left to discover about soil.

This image is familiar to most people, I think.

It suggests the human position of supporting the soil to support everything else that it carries. It also suggests something about the regenerative life-giving power of soil. But if you ever wondered or wanted to ask, “where does that power come from?” that power comes from carbon. It comes from the carbon cycle

This is the good carbon story.

This is a story that has about 18 and a half percent of me, or 13 odd kilos, being made of carbon standing here talking to you. Please don’t try and calculate my weight, it’s just as rude as asking my age.

We need to start by having a look where all the carbon on the planet is — because it really does help to look at where it’s residing. This is a diagram that is proportional to where the carbon is hanging out. The rock pool goes right off the page. It’s very large. Lots and lots of carbon, but it doesn’t go anywhere. It’s rock.

It holds the geological time.

The deep ocean pool over there also holds a lot of carbon, but its turnover time is about a thousand years — so it’s a bit longer than what really matters to our culture now. All the action is in all those splodges at the top — in the top left there — that is life. That is the living carbon cycle. That is where we exist, that is where everything that we know is, right there.

You can see the proportional amounts of carbon in them, and look, lots of carbon in the soil.


That big splodge, down on the bottom, that says Fossil C store, is all the carbon in the coal, oil and gas reserves that we know of on the planet. This is the stuff still in the ground. The little splodge above is how much we’ve burned in the last 250 years. That is what all the fuss is about.

That is the bad carbon story there. We hear a lot about that.

We’re looking to put that much out again in about forty years on current trends.

Now carbon is carbon and that carbon has gone immediately into the living cycle up there. Once it’s out, it’s carbon dioxide, there’s no distinguishing it, because it’s fossil carbon store comes from ecosystems 300 million years ago. A carbon cycle that was going on then — this is what’s stored in the ground, holding the energy in it. Because it originally comes from photosynthesis, pulling energy from a very old soil, or younger soil.

Younger soil.

To really get what this means, to try and get through this, this is a conceptual diagram of the annual carbon cycle, without any human industrial interference. These numbers are in billions of tonnes of carbon, that’s elemental carbon, there’s no carbon dioxide equivalents anywhere in my talk. What I want you to see is that the air and the plant, soil and ocean, the interchanges between them, are balanced.

So what goes down is also coming back up.

These are very large numbers and there are natural inputs and outputs but these inputs are actually really quite small, when averaged over a long time, and over years, time frames that matter to human culture, and the burial of things, like sediment in the ocean, kind of balances it out.

We’ve got a really large amount of carbon that is moving around the living system — that is essentially materially closed.

To give you an idea of how large that number is, if no carbon was returned, at all, to the atmosphere, to the air from the plants, soil or the ocean — it would take approximately three years to strip all the carbon out of the atmosphere. That is how fast it is cycled around.

We want that to happen. this is life.

That is how much carbon we have put in, in 2010, it is 8.3 billion tonnes — the majority of that comes from fossil carbon sources (so it is carbon from a very long ago ecosystem) into today’s. Hence that carbon is now building out because it is an addition with no removal. This is why what can look like quite a small amount can have such a large effect –because our carbon cycle is a materially closed system, and suddenly we’re adding more.

And every year it’s adding up.

So the movement through the different pools — it takes time to move through all of them, and we know it’s building up in the atmosphere, and we know it’s moving into other pools.

It can all get very depressing.

But thankfully I think that, most the time, most of the time, actually, I think about this, and I think about replacing the lost carbon store in soil — the carbon that has been removed through change of land-use because the sources of carbon that we’ve added to the atmosphere have not just been fossil fuels, they have also been loss of capacity. Loss of living biophysical capacity So that is the main thing I find of great interest there.

Having more carbon soil is really quite important for many other things.

Offsets are interesting but they’re not the main game.

I’d really like to demonstrate to you what this actually means and I’d like to just quickly show you this soil here, is a cropping soil. It’s been growing wheat for forty years and it has quite low levels of organic matter. When I say organic matter in soil, it’s interchangeable with carbon, organic matter is half carbon. It also carries several other nutrients with it. This is a soil from a pasture — adjacent — so they are the same soil types.

This has got roughly twice as much organic matter, close to what it had in its native condition. this one has lost it, this one has still got it.

This is linked to all the other benefits that we feel are really important, almost more important than the carbon for carbon offset purposes. We have structure and we have nothing. That comes apart, this one stays together. I can actually break it, but it holds its shape.

This characteristic is linked very strongly to benefits flowing to urban people. The benefits of good healthy soil, with lots of carbon, flows to everyone. It is not just people in rural areas, it’s people in the city too. If anything, they get the majority of the benefits because they are the majority of the people and they’re not putting in a lot of work.

I’m trying to be nice about it.

This is one of the benefits of more carbon in the soil: healthy ecosystems, good clean water, because soil with lots of organic matter cleans the water and it helps our hydrological cycle function. This is what I’d really like to talk about first, in my talk, is function.

Here is some of the other benefits of nice healthy soil, with lots of organic matter, it is a massive biodiverse ecosystem.

Aside from the very necessary biochemical transformations that these little critters do for us, and keep the ecosystem going for us, they’re also an amazing source of things like antibiotics, all those really good antibiotics came from these guys. Things like novel enzymes, novel transformation, biochemical transformation, that are far far more efficient than our industry Really makes us look like babies in terms of chemistry.

Another benefit, lots of carbon in the soil keeps your plants healthier. Incidents of plant disease, in soil with enough organic matter so that it is functioning, is far less — this is well documented.

Good food. Good food, lots of city people need to eat. Everyone needs it and it’s really hard to overstate this, I often end up understating it, it’s pretty fundamental.

And this one: sponge. Lots of organic matter in the soil makes the soil turn more spongy which holds a lot more water — which affects the flood cycles —  so  flood peaks are lower and there’s more water in the river for longer.

All these benefits go to urban people but I don’t really know about them, I don’t really appreciate them, I don’t really think about them.

This is kind of why, when we’re talking about getting soil to be more like this, with more carbon, and paying for a bit of carbon offset, we think that the urban people should be paying for the rest of it as well. But that’s just us scientists, nobody really listens to us very much.

We have a problem — with carbon in the soil — because much of it has been lost from the agricultural systems.

Now there’s a huge diversity in the levels, so I am going to generalize here. This makes me sad because there are no plants there to be pumping carbon into the soil. There’s no mulch to be breaking down and decomposing, putting that carbon through the soil. When I see this, I see carbon loss. I don’t see carbon cycle and I want to see carbon cycle. I want to be very up front about that.

This is another outcome of poor management of ground cover — with less ground cover, water carries the soil away, which also actually carries the carbon itself away. Filling the rivers with soil, because the soil has got to go somewhere.

A lot of these issues, they span a far greater time than just one generation, a lot of these issues go back 150 years or more. I’ll get to some more of it later.

This is the elephant in the room for soil carbon sequestration because organic matter carries several other nutrients with it. If we get all of the nutrition from these sources —  on the left that is a nitrogen production factory, nitrogen synthesized with the power of fossil fuels, the middle is a phosphate rock mine, there is only so much phosphate rock, on the edge there is a potash mine, there is only so much.

These sources of fertility are awesome. they have helped us produce so much more food.

But there is no carbon in the delivery of this fertility.

This is part of why we have this problem.

This has grown wheat for a long time, it’s been fertilized conventionally, and it has grown its wheat, but it has lost its carbon. We need to get the fertility cycles and the carbon back together. Because before we had synthetics sources, and mining sources, for more nutrition – which you kind of need (there’s a lot of us) — we had to rely on the carbon cycle, the good carbon story, to move that fertility around.

There’s a difference here, between thinking in a straight line and thinking in a circle — the straight line thinking is the industrial approach: the fertility in a bag — don’t worry about the carbon,  worry about the carbon cycle. Carrying that fertility through the plants in the soil, in the organisms, you don’t have it in a bag, it’s cheaper, it’s quicker, it’s better.

It has produced us a lot of food, but we have a problem in that nitrogen is tied to fossil fuel prices, or energy prices. There’s an issue there, it’s always going to get more expensive at the moment, and that makes food tied to energy prices not very good. That there is only so much of these mineral reserves, the phosphate rock and potash source of potassium in the world. There’s only so much.

Nature doesn’t think like that. Nature thinks in a cycle.

Remember the carbon analogy I showed, if there was no carbon to the atmosphere it would run out, very quickly. Everything in nature, especially these plant nutrients, are recycled. Once it’s in the natural system, she really does not want to let it go. This is the kind of a circular thinking I see many farms starting to take really strong advantage of.

There are three pathways for carbon into the soil. the first one, on your left, is charcoal.  After the plant picks the carbon out of the atmosphere, these are the three options. Charcoal is produced in fires, with very low oxygen levels. It is not really a biological process unless you count the humans doing it. So we’re not really going to talk too much about that.

The middle one is humus. That is all dead plants, dead animals, waste, as it breaks down and the microorganisms decompose it. Whenever someone says “decomposing” what it means is that this material is being eaten up and broken apart by all the microbes in the soil. We can’t see them, unless we use microscopes etcetera, but this decomposition doesn’t happen without them.

Biologists call it the eye of the needle.

All this material to be recycled — and for the nutrients in it to be released, for the plants, for the next stage — needs to pass through the microbial system.

The one that’s actually really quite interesting is the one at the end. This is extradates. This is what I imagine they look like. These are the sugars that plants give to their associated microbes. Purposefully. It’s between 5 and 20 percent of the carbon that they fix. It’s actually quite a lot that they are deliberately letting out of their roots to feed these guys.

There’s quite a reason for this, and what you think that reason is depends on what you think the environment is like,  and what nature is actually like. If you think nature’s all red in tooth and claw, and it’s all competition between every species and we’re all trying to get ahead? We’ve got the system on the left.

If you think that maybe nature’s a little bit more competitively cooperative, where its groups of species together actually do better than species just by themselves, then we get something on the right. My money is on the right

This is a classic example of symbiosis.

Here’s a clover plant with a nitrogen fixing bacteria in its roots. These are two variants of a control, and one that has had the signaling molecule knocked out of it, so the plant actually says please come and infect me, I want you to come and get in my roots. See how much better these two species are doing when they’re together?

Synergistically working together

Another example of a farmer who is using this kind of approach in managing his pastures and diverse assemblage of creatures to ramp up the carbon cycle through the soil. We want that churn because that churn gives top soil like this.

As a social scientist I get very happy when I see this.

This is nice.

This is the effect of managing for biology. At the top we have a biogenetically managed dairy. I would say it’s managed for biology

At the bottom we have a conventional dairy. You’re looking at soil profiles and the black space is – the black is actually space.

So you see the ones at the top are actually a lot more spongy.

Structure in soil is a result of microbiology and then functioning and passing the carbon cycle through its soil.

There is lots of compost returning to farms. There’s starting to happen to actually tie these nutrients strings in, the consequence is that a lot of crop stubble and waste, that is leftover, actually decomposes faster because you’ve got microbes there to turn it over.

This is thinking in a circle or thinking in a straight line.

There’s a lot of a straight line thinking happening in the city. In fact, I’d say that’s even more of it happening in the city, than there is in the country

Half of that is organic material, and it goes into landfill, and it goes to produce methane, so all of the carbon, and the nutrients with it, are being buried and taken out. So somewhere soil is going hungry.

This is green waste collection and compost collection schemes.

Some of them already exist. People are starting to challenge that straight line thinking, and recycling.

We need to hook up the excesses of the city back to the deficits of the soil in the country.

This is a sewage treatment plant for very large human [inaudible]. We concentrate large amounts of nutrients into our cities and then, essentially, once we’ve eaten it and finished with it, that nutrition is spread and dissipated into the environment, it is not returned back to where it came from. This is a real problem in the longer-term.

There are two systems where people have used that circular thinking to keep that nutrition in the living system.

We don’t want to let it go, we want to keep it there.

That is the good carbon story.

That is this side of things, where we can keep the nutrition in our living systems. This side is where we have much soil at the moment We can actually move back that way, using the biology of the good carbon cycle through the soil, to carry that nutrition through.

Hopefully, by the time that I’m an old woman, we’ve all gotten on board — including the people in cities — we’re going to have really nice streams again, and I’m going to be able to find a very nice fishing spot somewhere in there.

Originally from Far North Queensland, Ichsani Wheeler is a young scientist as well as a mad keen gardener, lover of worms, fungi, and all lowly compostable things. With a succinct soft spot for home made aquaponics systems and soil that smells good enough to eat she has a long standing passion for agriculture, the environment and pragmatic approaches to the challenges of sustainability.

After graduating from a Bachelor of Land and Water Science she worked as an environmental consultant to the design and development industries. Her project experience primarily focused on designing natural storm water treatment systems, waterway rehabilitation and urban design. Returning to take-up a PhD in 2009 examining soil carbon sequestration on farms she is committed to highlighting the importance of healthy, functioning soil as vital to a healthy, functioning society.


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  • 30/10/2016 at 19:10

    Keys to Building a Healthy Soil (Gabe Brown)


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