The need to place more emphasis on “carbon flows” for profitable
farming in extension programs
Alan Lauder
Mareeba Rotary Field
Day Carbon Farming
Initiative Tent
29 & 30 May 2013
Today I am going to discuss carbon flows, which is the aspect of carbon that we pay too little
attention to in extension.
Before discussing carbon flows, I want to show you one of the repercussions of too much
tree clearing.
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The natural world can’t
function without
“carbon flows”
The main point I want to raise today is that we have become too preoccupied with carbon
stocks and measuring carbon and not paying enough attention to carbon flows. Just talking
about carbon stocks is far too narrow. If you want to understand how your paddocks
function, how to make more money, how to produce better environmental outcomes
including greenhouse, how to reduce the impact of dry times, then all of these things will be
clearer if you understand the concept of carbon flows.
Not appreciating the importance of carbon flows is similar to an engineer ignoring gravity.
The most important thing that happens in your paddocks is that carbon comes down from
the atmosphere and flows through the paddock above and below ground, then returns to the
atmosphere. In the process of doing this, carbon keeps your paddocks productive and
healthy. For the duration of my talk, visualise carbon always moving. (Hand motion down
and up. Always moving)
To understand the difference between the concept of carbon flows and carbon stocks, any
carbon that is flowing through the paddock at the time of measurement, is recorded as a
stock. Carbon flows are ongoing while carbon stocks are a measurement at one point in
time. Carbon stocks at the time of measurement are called short term (labile), medium term
and long term (non-labile).
Thinking carbon flows is to be aware of how much activity is occurring in your paddock.
It is understandable that carbon trading is focused on measuring carbon stocks, given
trading can’t occur without measurement. Unfortunately, this emphasis on stocks and
measuring has been allowed to dominate extension and held back broader discussion on
how landscapes really function.
Before I go any further, every time I use the word carbon, I want you to think carbon
compounds. Apart from diamonds and graphite, carbon is always attached to other atoms.
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The next point is that regardless of which compound carbon is currently in, it is likely to move
into another form. In some cases very quickly, in other cases very slowly.
What follows Carbon?
• Energy
• Nutrients
• Water
These three are central to production. The better you manage carbon flows, the more of
these three you have access to. What I will explain later, is how energy is carried by carbon
flowing through your paddock.
I want to start by showing you carbon flows in action in the real world.
These images will explain how it was increasing carbon flows that led to a long term
degraded claypan turning into productive country. The images will help you understand the
important processes that carbon flows activate.
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This slide is about restarting carbon flows. It is an extreme example to highlight that
functional landscapes rely on carbon flows.
This is a long term claypan, where the soil component of resilience had failed years ago.
This is planting a source of carbon flows when nothing could establish naturally from seed to
do the job.
The left hand image is Old Man Saltbush 12 months after it was planted into a barren
claypan. The right hand image is another year later. Sheep are responsible for the lack of
leaves on the saltbush. They were after some protein to increase the digestibility of their diet.
As an aside, if you want to enter methane reduction trades, you have to increase the
digestibility of the diet.
In the right hand image, you can see carbon is now flowing in the area around the shrubs
where couch and other plants have established. In other words, the landscape is becoming
more resilient. It is the carbon flows introduced by the planted saltbush, which has improved
the soil. As the soil improved, grass and other plants were able to germinate and further
expand the area that carbon is flowing through.
All this happened over a two year period at Yelarbon, when rainfall was well below average.
This highlights that with good management, dry times do not have to ruin the health of your
landscape. The critical thing in dry times is that you allow what rain does arrive, to produce
some inflow of carbon. How well you let plants grow after rain determines how much carbon
flows into your paddocks. This will be one of the themes of today’s talk.
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This photo was taken 3 years after the saltbush was planted.
Your day job is converting
water molecules into
carbon molecules
This photo was taken 5 years after the saltbush was planted.
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What follows Carbon?
• Energy
• Nutrients
• Water
This is another photo after five years.
After carbon started flowing again, energy, nutrients and water all followed. Plants are now
growing, which is introducing energy. The build up of organic matter is increasing nutrient
supply. Looking at the prolific grass, water is obviously getting in now. It wasn’t before as the
next slide shows.
This photo was taken immediately after a few mm of rain.
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Relating these images to the CFI program, this paddock now has more carbon in it and the
methane outcomes are improving.
After seeing the positive outcomes in these pictures, I want you to think in reverse to
appreciate how management which reduces the flow of carbon into your paddocks, also
reduces production and degrades your paddocks, making them less resilient.
Carbon management not explained
I spent thirty years running a grazing business before leaving the land in 2000. Not once in
those thirty years, was it ever explained to me, that my success relied on how well I
managed carbon in the paddocks. Discussing land management in terms of carbon
management simply wasn’t part of extension.
It is ironic that the climate debate has introduced carbon into extension, when discussing
carbon and what it does, should have always been central to discussing land management.
It will probably take many years to see adequate attention paid to the “carbon flows” aspect
of land management given past uptake of new approaches by institutions.
It is the ongoing flow of carbon that makes it possible for all the life on this planet to exist
above and below ground. We are 18% carbon and I assume cows are similar. Grass is
about 45% carbon when dried. All the life that lives in the soil and is responsible for keeping
it well structured and fertile, also need carbon to build their little bodies, regardless of how
small they are.
It is carbon that is responsible for carrying the energy which all life relies on. Put simply,
carbon is the main building block of all life and responsible for keeping all life functioning.
Think of carbon as the organiser. It organises so many processes as it flows through your
paddock.
To help you understand the concept of carbon flows, carbon keeps moving out of its existing
structure into new structures. The carbon atoms are always moving. Carbon is joined to just
oxygen when it is carbon dioxide, then after photosynthesis it is in the more complicated
carbohydrate structure in plants, then another form in cows and so on. The same process of
carbon being in ongoing change is also occurring in the soil. Carbon keeps changing its
structure as it keeps moving.
Your day job is recycling carbon and in the process turning some of the carbon that is
flowing through the paddock, into saleable carbon products, like grain, meat, fibre or hay.
Selling cattle is harvesting carbon when it has entered the cattle part of the food chain.
A rural producer sells something that has lived and all life relies on the ongoing flow of
carbon through the landscape. Nitrogen is just one thing that joins carbon in building life.
You know this combination as the carbon:nitrogen ratio of life. There should be more
attention paid to this ratio in extension, as it influences the outcomes of so many processes.
In 2010, one of my Carbon Corner columns “Carbon before nitrogen” said in part. “A bare
paddock has no carbon while frosted or rank grass has little nitrogen. We can supplement
nitrogen when it is in short supply. However, it is not commercial to supplement carbon when
it is short. For anyone who doubts the importance of allowing plants to grow after rain and
build up carbon, try feeding lick blocks to sheep or cattle in a totally bare paddock. Correctly
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manage carbon flows from the atmosphere to your paddock and you will still have options
when it has not rained for a while”.
It is how well you manage the flow of carbon through your paddock that determines how
many cows there will be in the paddock. Remembering that grass is 45% carbon, there will
be no grass in the paddock without carbon flows. The good operators have the ability to
generate small flows of carbon from isolated falls during dry times.
When people get their head around the flows way of thinking, they quickly discover that the
bulk of the carbon movement in the paddock, involves short term carbon compounds, not
long term carbon compounds.
Above ground carbon important too
We are too focused on just soil carbon in extension. Extension does talk about ground cover,
but we never talk about it in terms of carbon. Carbon flows only seem to be discussed as
carbon when they are below ground. Institutional extension services focus on stocking rate,
pasture utilisation rates and maintaining a minimum level of ground cover. This is 1980’s
science as a government employee explained to me and is a disservice to rural producers
and export income. What sets the level of ground cover is how much carbon a particular
form of management allows to come in after rain. (Grass is 45% carbon when dry).
How much of the ground cover is then consumed is important, but it is the second decision
you make. If you are just thinking stocking rate, then carbon flows are not part of your
thinking. The only time we seem to think about carbon being above ground is in trees, but
this is only because it is seen as long term carbon. Grass is short term carbon. This
highlights the misplaced preoccupation with long term carbon when management changes
are reflected mainly in short term carbon.
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Paddock SOC 1.5%
Labile
Paddock SOC 2.5%
Non labile
Recalcitrant
Derived from: Chan et al A farmers guide to increasing soil organic carbon under pasture. NSW Industry
and Investment 2010
This slide demonstrates the importance of short term carbon. The red section is the faster
moving short term carbon and the black section is the very slow moving long term carbon.
It demonstrates how ratios of short and long term carbon vary as soil organic carbon is
increased.
When soil organic carbon went from 1.5% to 2.5%, the change was driven by increases in
the short term carbon called labile carbon. Look closely at the size of the black section,
which is non labile carbon (long term carbon), and there is virtually no change. The
percentage of long term carbon has changed on the left hand diagram, but this is because of
the increase in the labile carbon (red section) has changed the total.
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Two paddocks can have
equal long term carbon
stocks, but it is the one that
has the most carbon flowing
through it, that will have the
highest level of production.
This slide makes the point that we are thinking too much in terms of “measured carbon
stocks” and not putting enough emphasis on the carbon flows aspect.
Remember I said earlier that carbon is always moving.
It would be clearer for farmers if we discussed the different types of carbon in the landscape
in terms of how quickly or slowly it moves. Some of the carbon moves very quickly through
the paddock on its way back to the atmosphere. Some stays a bit longer and some of the
carbon is moving very slowly. The faster moving carbon has a different role to the slower
moving carbon.
This may seem like a radical proposal however it brings the land management debate back
to discussing exactly what all the different forms of carbon are doing.
Carbon trading is more focused on the slow moving stable forms of carbon, while rural
producers set out to increase the volume of the faster moving short term carbon. If you want
to increase production in the short term, it is the fast moving carbon that increases
production, not slow moving carbon.
In Australia there is a much better understanding of soil carbon in cropping systems than in
pasture systems. Chan is one of the more knowledgeable people when it comes to pasture
systems.
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Paddock SOC 1.5%
Labile
Paddock SOC 2.5%
Non labile
Recalcitrant
Derived from: Chan et al A farmers guide to increasing soil organic carbon under pasture. NSW Industry
and Investment 2010
Coming back to Chan’s pie diagrams again, they explain why cropping systems are often
returned to pasture again to rebuild the health of the soil. With good management, pasture
systems have the capacity for higher soil carbon levels simply because there are higher
carbon flows over time than in cropping. Just as higher carbon flows under pasture improve
the productive capacity of paddocks when returned to farming, so it is that increasing
productivity of grazing systems also relies on higher carbon flows. Chan’s pie diagrams
focus us on labile carbon as the component that changes in the short term when
management changes.
It is accepted in the scientific community that stocks of long term soil carbon are slow to
change, which reinforces the point that long term carbon can’t to be responsible for short
term increases in production.
The energy is sitting in the red pool and energy is central to production.
I am not suggesting that long term carbon is not important, because it is. The better soils
have higher long term carbon levels, which is why you pay more money for them. What I am
saying is that long term carbon is the carbon you have far less control over.
The bulk of the carbon movement in your paddock is the red section. This is why extension
programs should place more emphasis on carbon flows to increase the profitability of
farming. Increasing carbon flows also improves environmental outcomes.
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Decomposition of
organic material
and conversion to
SOC at different
stages. Source:
Stevenson 1986
This diagram highlights that carbon flows have to be maintained because carbon keeps
leaving the system. The arrows on the CO2 sections represent the loss of introduced carbon
via consumption. Apart from fire oxidising carbon compounds, the oxidisation process relies
on one life form consuming another and releasing CO2 in the process. The
diagram highlights that the outcome of photosynthesis is being reversed with every
consumption event. You can see some of the original flow heading towards longer term
carbon as it becomes less and less digestible.
The carbon that flows in after rain initially goes into the fast moving carbon pool. Then some
finds it way into the medium term pool and finally a little into the long term pool.
As a general comment, 75-80% of carbon that enters the soil will be gone within
twelve months. The actual amount is determined by moisture levels and temperature. This
highlights that if your management is not focused on carbon flows, then you run the risk of
running short of this commodity.
It took me years to develop my current understanding of stocks versus flows and how best to
explain the difference. What worked for me is that measurement of stocks is taken at just
one point in time. Any carbon that happens to be moving through the paddock at the time is
measured. There is a lot of carbon that moves through the paddock that misses
measurement. Root exudates, which are carbon flows, are outside measurement. I am
informed that only about ten percent of the carbon that enters the soil is actually measured
as soil organic carbon (SOC).
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You can be confident with the long term carbon measurement as it is measuring slow
moving carbon. However with the faster moving carbon, you have to be careful of the
circumstances under which you measure. It is very easy to catch a spike that is not
representative.
Now coming back to the CFI. Any carbon that is in the stable long term pool has to start the
journey as fast moving carbon, so soil carbon trading relies on the same management as
making more money. You have to increase carbon flows. In fact this is the first example of
the broader rule – “The greenhouse outcomes of the grazing industry are a reflection of
economic efficiency”.
There is a reason why a paddock is more productive when carbon moves faster. It is simply
because everything that is joined to carbon as it moves through the soil, becomes available
to plants sooner. Think energy and nutrients.
It is important to remember that the long term soil carbon is also flowing, but at a slower rate.
Short term carbon moves faster if more nitrogen is joined to it. This is because carbon
compounds can be consumed faster. Time is too short to discuss how this same process
applies to cows digesting high protein diets quicker than straw.
If you enter into methane reduction trades, you need to ensure that carbon is moving faster
through the cow’s rumen. More nitrogen in the diet will achieve this.
For those interested in soil carbon trading, it is important to be aware that there is always a
little bit of carbon flowing out of the long term carbon pool.
Carbon flows are going both ways, in and out.
Steve Bray who speaks after me will draw your attention to why there are limitations to
increasing longer term soil carbon in this region.
Photosynthesis and energy storage
Because all life relies on energy I will now explain how carbon flows carry energy.
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6 CO2 + 12 H2O + Light
Carbon + Water + Chlorophyll
Dioxide
C6H12O6
+ 6 O2
+ 6 H2O
Carbohydrates
(Glucose)
+ Oxygen + Water
This equation of photosynthesis shows how energy is stored in plants when they grow after
rain.
How the energy is stored, is that the carbon in carbon dioxide, now forms more complex
carbon bonds in carbohydrates. (point)
The energy is stored in the more complex bonds.
These more complex bonds, are achieved by using the energy of the sun to rearrange the
atoms.
This is what scientists refer to as construction of energy.
How all life sources energy during consumption, is to break these complex bonds and
release the energy. It is a case of reversing photosynthesis and converting the
carbohydrates back to carbon dioxide. We breathe in oxygen to oxidise the carbon
compounds and then breathe out carbon dioxide.
It is short term carbon and not long term carbon that is responsible for energy availability.
Remember the two pie diagrams. There is a lot more energy residing in the soil with the
higher short term carbon levels created by higher carbon flows in the recent past. Just as
more nutrients are available with higher short term carbon levels.
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Potential for increasing soil carbon
This photo was taken not far from the claypan that the saltbush repaired. It highlights that the
best option for trading soil carbon would be to start with a very degraded site that can only
improve.
I quote a soil scientist in the Department of Climate Change who commented on this image.
“My guesses...
Looks like the soil is a sandy loam to me and there is a striking difference between the
vegetation cover either side of the fence.
It looks like a semi-arid region with a rainfall less than 350mm/yr.
Assuming that the vegetation cover difference has existed for some time. (keep in mind that
a change in vegetation such as shown could increase soil C by 0.2 – 0.5 t/ha/yr. Therefore if
the change has been for 10 years then maybe an increase in soil C of about 2-5t/ha or for 20
years 4-10t/ha).
Considering this level of uncertainty I am guessing for the bare paddock anything from 15-25
t/ha (0-30cm) and for the vegetated paddock anything from 35-50t/ha (0-30cm).”
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Carbon flows different to the carbon cycle
Those in extension not thinking carbon flows the way I am presenting the concept today,
think that the carbon flows discussion is simply along the lines of the typical carbon cycle
diagram. The carbon cycle diagram is a one dimensional discussion explaining that carbon
cycles, whereas the carbon flows discussion is about what carbon is achieving as it moves.
It also focuses on how you can increase the flows of carbon. It explains why current carbon
flows are influenced by all the feedback loops that come into play depending on previous
management.
The resilience of your paddocks and their ability to respond to falls of rain, especially in dry
periods, is determined by your previous management of carbon flows. Now an example of
how past grazing management impacts current carbon flows.
The right hand (RH) side of the fence is a pasture paddock, not a farming paddock. Notice
the water right to the fence line, then nothing on the surface over the fence.
This slide highlights what can happen, when animals over time are allowed to eat grass
every time it tries to grow after rain and so greatly reduce carbon flows into the paddock. The
sick plant on the left has depleted energy reserves because of inadequate carbon flows in
the past, so is struggling to come out of dormancy, after what was handy rain. Energy
reserves are short term carbon. A bit of resting after rain, to allow plants to let energy in, is
like keeping some charge in the battery.
To understand the failure of water infiltration on the right hand side of the fence, think of the
soil as a construction site. What lives in the soil, keeps it well structured and fertile. If plants
are not allowed to grow and feed carbon compounds to all the workers in the soil, then they
die.
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These images highlight that resilience relies on carbon flows. Think of resilience as having
two components, plant resilience and soil resilience. Plant resilience fails first, then soil
resilience declines. This highlights that your animal management affects the soil, by effecting
plants first.
Now for photos taken on each side of this fence during a high rainfall spring.
This slide highlights that WUE relies on plant resilience and soil resilience. It also highlights
that present carbon flows, rely on past carbon flows. Just as money makes money, so
carbon makes carbon. These photos explain what is behind disappointment when a paddock
does not respond to rain very well.
This image is a reminder that a farmer’s day job is converting water molecules into carbon
molecules. Rainfall is not the sole determinant of production.
Taking water use efficiency further, perennials bring down more carbon over time than
annuals do. I wouldn’t like to be trading soil carbon on the RH side of the fence.
Short and long term resilience
The fast moving carbon supplies short term resilience. On the other hand, the slow moving
carbon supplies resilience over time. It protects the long term survival of the system.
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Management that increases fast moving carbon maintains larger root systems in plants
which allows them to access more moisture and nutrients to grow. This increases short term
resilience.
Management that increases carbon flows maintains a larger root system and boosts plant
resilience.
One way water gets into the soil is by running down beside roots. The level of water
infiltration and to what depth, is influenced by the volume of roots and their depth. This is
called the wick effect.
The fast moving carbon is part of energy reserves central to short term resilience. It is
ground cover that increases water use efficiency through reducing evaporation by lifting wind
and keeping the sun off the soil.
Root exudates are soluble carbon released into the soil by root tips and this supports soil
microbes to make nutrients available to plants. Root exudates are some of the fastest
moving carbon in the system.
Organic matter that supplies nutrients is short term carbon.
It is short term carbon that maintains soil biology responsible for creating macro-pores in the
soil to enhance air and water movement. These macro-pores will still be there after this fast
moving carbon that facilitated their construction is back up in the atmosphere. Compaction
occurs in a lot of soils when carbon flows fall.
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The slow moving carbon (the long term carbon also called humus) is the other half of the
resilience story. It supplies the long term resilience of your paddock. It greatly increases the
nitrogen storage capacity of the soil. It provides better soil structure which provides spaces
for water. It changes the pH of the soil and so buffers against any toxic elements present.
Because it is more stable, it is much less affected by management.
It must be remembered that every soil and every location has an upper limit to the amount of
slow moving carbon that can be accumulated.
Humus which is long term carbon, helps hold soluble nutrients that would otherwise escape
the paddock and end up in waterways.
The Carbon Grazing principle
I now want to go back to the very basics of when carbon flows enter the paddock and how to
maximise them. None of this is rocket science but we often overlook the obvious.
The Carbon Grazing
principle draws attention
to when the bulk of the
carbon flows in from the
atmosphere
The size of carbon flows following rain is influenced by your management. The only way that
carbon can move from the atmosphere to your paddock, is via photosynthesis. Given that it
is moisture that promotes photosynthesis, then it is moisture that promotes the introduction
of carbon. Nature has designed the system, so that water activates the flow of carbon into
the landscape.
If you think about it logically, the bulk of the carbon enters the landscape in the short period
following rain. This highlights the need, to focus management around this point in time.
Letting animals eat plants when they are trying to grow after rain, reduces photosynthesis
and in some cases, completely shuts it down.
There are some subtle realities that underpin the Carbon Grazing principle. Remember, it is
a principle, and not a new land management system. It applies to all successful land
management.
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Because there is no pattern to when rain arrives, in other words, when carbon arrives, the
message is that pasture rest is TIMING and not TIME. Basing resting decisions on a certain
period of TIME, is no guarantee that carbon will arrive.
This is not an attack on cell grazing, where cells may be locked up for 120 days. Cell grazing
implements the Carbon Grazing principle, because when rain arrives, the bulk of the cells do
not have animals in them.
Stating the obvious, continuous grazing never implements the Carbon Grazing phase of rest
after rainfall.
It was scientists I met in South Africa, who started me thinking. “How long do pastures need
to be rested for to keep paddocks resilient?” Remembering that resilience relies on carbon
flows. They suggested that with average pastures, removing animals for 3 – 8 weeks after
rain, increased pasture production by 50 – 80%. In other words, carbon by about 25 – 40%.
When people say they can’t afford to rest pastures, it begs the question, can you afford not
to.
Carbon Grazing is 4 – 6 weeks rest after rain. The period does not commence until the
plants actually start growing. Also, it is important to not get caught up on the exact time, as
factors like temperature influence the necessary time. Carbon Grazing is about maximising
carbon flows. It is the window of opportunity too many people miss.
Carbon Grazing should not be confused with wet season spelling. It is “strategic” rest.
Financial analogy
To put fast and slow moving carbon into a commercial analogy, think of cash flows versus
capital. Cash flows is the fast moving money that keeps you viable, just like it is the fast
moving carbon that keeps you viable. Think of the slow moving carbon as really part of your
capital base, just like cattle yards and buildings.
The fast moving carbon makes money for you because it feeds all the life in the paddock,
including your cattle. It maintains larger root systems in your plants so that they can access
more moisture and nutrients to grow. It is part of energy reserves that determine how well
plants respond to what rain falls, especially important in marginal years. It is ground cover.
It is organic matter that supplies nutrients.
Soils that naturally have higher levels of long term carbon (slow moving carbon) are more
resilient and productive over time.
Erosion is an immediate reduction in earning capacity, because it removes both short term
and long term carbon.
Summary slides
The next three slides provide a summary of carbon flows principles. I am grateful to Patrick
Francis, the former editor of the Australian Farm Journal, for constructing the slides.
The three slides have the same format. They all rely on pictures and graphs to demonstrate
the above ground and below ground outcomes, depending on how well carbon flows are
managed.
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Applying the Carbon Grazing principle
Pasture rest after rain building labile carbon
above and below ground
Decomposition of organic material and
conversion to the continuum of SOC
when the importance of
carbon flows is recognised
and managed (Derived from Stevenson, 1986).
Many attempts have been made to differentiate SOC into
various pools of varying lability and the more labile pools
have been used as sensitive indicators of changes in
response to land use management (Resource NSW 2002)
REST AFTER MORE RAIN
CARBON FLOWS, WUE & RESILIENCE
LABILE CARBON STOCKS
NON-LABILE CARBON STOCKS
Source: www.moffittsfarm.com.au
This slide demonstrates the outcome of applying the Carbon Grazing principle, which
maximises carbon flows each time it is applied.
The first point to note in this slide is the positive effect on ground cover, as the photos show.
The wording on the photos makes an important point that is often overlooked – ground
cover is labile carbon. It was discussed earlier that the carbon flows debate extends past
what happens in the soil to also include what happens above ground.
The pie chart is a reproduction of the earlier one discussed, where Chan et al showed that
the increase of soil organic carbon from 1.5% to 2.5% was just about solely due to the
increase in labile carbon. This makes sense, because the increased carbon level would be a
reflection of the increased amount of carbon flowing through the paddock.
It has to be remembered that if better management is stopped, then the total soil carbon
level will drop. Lower carbon flows would be reflected in lower labile carbon levels in the soil.
Likewise above ground, lower carbon flows would see a drop in ground cover.
Take note of the actual size of the pie charts in this slide. The pie charts in the next two
slides will be smaller.
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The green graph line reflects carbon flows over time. You will notice that water use efficiency
(WUE) and resilience parallels carbon flows. This is consistent with WUE relying on
resilience and resilience relying on carbon flows. The green line charts your success in
converting water molecules into carbon molecules – which is your day job.
There is a reason for the slight increase in labile carbon in the second pie chart. Current
carbon flows rely on past carbon flows. It is the slightly increased short term resilience
provided by the previous rest after rain that has influenced current carbon flows. In well
managed paddocks only marginal changes are likely – it is more a case of maintaining
resilience and hence maximum possible carbon flows given the circumstances. It is poorly
managed paddocks that supply the greatest opportunities for increases.
Putting management aside, the labile carbon stocks are set by seasonal conditions, and will
fall in dry years. It is available water that influences carbon flows. Sometimes water does not
arrive and sometimes your management is responsible for it escaping before being able to
generate carbon flows. Rain can either enter the soil or run off into the creek.
The red and black graph lines represent labile carbon stocks and non-labile carbon stocks.
The pie charts are representative of the direction these lines take.
Decomposition of organic material and
conversion to the continuum of SOC when
the importance of carbon flows are
unrecognised and unmanaged
(Derived from Stevenson, 1986).
Pasture set stocking
– labile carbon maintained
CARBON FLOWS, WUE & RESILIENCE
SMALL CARBON FLOWS
AFTER RAIN47%
50%
MORE RAIN
& NO REST
50%
LABILE CARBON STOCKS
Source: www.moffittsfarm.com.au
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NON-LABILE CARBON STOCKS
Page 22
This slide is set stocking. It represents a system that is operating at a lower carbon
equilibrium above ground and below ground. The first thing you notice is that the pie graphs
are smaller than the previous slide. The labile carbon is a much lower percentage of total soil
carbon simply because carbon flows are smaller.
There is only a marginal increase in the green line after more rain, which highlights that
carbon flows are not meeting their potential. Bare pastures have lower WUE. They do not
respond as well to rain and revert to the non growth phase quicker. This is reflected in the
lower percentage of labile carbon.
Pasture set stocking, dry season, then rain Labile & non-labile carbon loss
when the
importance of carbon flows are unrecognised and unmanaged during dry times
Decomposition of organic material and conversion to the continuum of SOC
(Derived from Stevenson, 1986).
CARBON FLOWS, WUE & RESILIENCE
SMALL CARBON FLOWS
AFTER RAIN
MORE RAIN
& NO REST
LABILE CARBON STOCKS
NON-LABILE CARBON STOCKS
Source: www.moffittsfarm.com.au
This is set stocking again. This slide brings in the impact of a dry season or drought
followed by heavy rain. It shows the risks with set stocking. The green line drops and is
consistent with lower carbon flows in a dry season.
The telling message is the extent of the drop in the labile carbon and non labile carbon from
wind erosion and soil erosion. This would not have occurred if the paddock had started with
better ground cover and higher labile carbon levels in the soil.
Lauder (2013)
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The wind and water erosion that has occurred has removed labile and non labile carbon and
this is reflected in the smaller second pie graph. Not only is the second pie graph smaller,
but it also has a lower percentage of labile carbon. The assumption here is that labile carbon
resides mainly in the surface soil.
The future earning capacity of this paddock has reduced. With the removal of labile carbon
there is a removal of stored energy and nutrients. With the removal of long term carbon goes
long term resilience.
Applying the Carbon Grazing principle
Pasture rest after rain building labile carbon
above and below ground
Decomposition of organic material and
conversion to the continuum of SOC
when the importance of
carbon flows is recognised
and managed (Derived from Stevenson, 1986).
Many attempts have been made to differentiate SOC into
various pools of varying lability and the more labile pools
have been used as sensitive indicators of changes in
response to land use management (Resource NSW 2002)
REST AFTER MORE RAIN
CARBON FLOWS, WUE & RESILIENCE
LABILE CARBON STOCKS
NON-LABILE CARBON STOCKS
Source: www.moffittsfarm.com.au
Looking at the first slide again, this paddock would not have been prone to the same
erosion. From a production perspective, there would be standing feed going into a dry spell
to allow the use of supplements.
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Take home message
The only time you can
build resilience, is the
short period after rain
It is not until we pay more attention to the carbon flows aspect of carbon, that more attention
will be paid in extension to promoting when the bulk of the carbon enters the paddock. This
broader focus will lead to higher production with the added benefit of better environmental
outcomes, including improved water quality.
It is applying the Carbon Grazing principle that builds and maintains resilience.
I would like to finish by saying that the only time you can prepare for drought is when it rains.
This is the only time you can increase your stock of above ground labile carbon.
END OF TALK
Lauder (2013)
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