ANIMALS CAN BE VERY SELECTIVE

We all know that grazing animals, especially sheep, are selective in what they eat. They graze selectively the best species of plants and also the best portions of the plant. The best plant parts are the palatable new growth.

Animals select new growth first, be it from grasses or edible shrubs

WHY DO ANIMALS SELECT THEIR DIET SO PRECISELY?

Animals select new growth because it has higher nitrogen (protein) levels. The digestibility of what grows on the tips is higher. As a generalised comment, allowing for different plant species and different soils, there is 2.5% nitrogen in new leaf and 0.5% nitrogen in the stem. This is why animals select plants that are already over grazed. They have been eaten back to ground level and only have new leaf to offer. This explains why animals will always keep returning to the same plants under continuous grazing.

As grazing animals need from 0.8% to 1% of nitrogen for maintenance (to stay alive) and more for weight gain or lactating animals, it is in their interest to select the best diet available. To calculate the protein level of plants, multiply the nitrogen content by 6.25. Cattle are not as precise as sheep, but they are still selecting new growth when they take the top off growing grass.

AN EXAMPLE OF HOW PRECISE ANIMAL SELECTION CAN BE

Measuring grasses that livestock have eaten is not easy, so one day I decided to measure the diameter of the stem at the point of bite on Old Man Saltbush plants eaten by sheep in a 4,000 acre (1,600 ha) paddock. We were left in awe at the precision of their selection. The table below documents what they were doing.

Stem diameter of tips removed from Old Man Saltbush by sheep (1inch = 25 mm)

Focusing on what was eaten, 49 bites out of 54 were selected from the stem diameter range 2.25 – 3.00 mm i.e. the new growth. They were basically avoiding stem >3.0 mm.

WHEN PERENNIAL GRASSES ARE AT MOST RISK

Perennial grasses are well adapted to drought but not to continuous defoliation. The most dangerous time for perennial grasses is a run of marginal years when stock eat all the new growth every time there is some rain. This results in root reserves being drawn on regularly with little replacement, and so some plants eventually die. This is what former CSIRO scientist David Freudenberger refers to as “the paradox of average years”. Green pick is ongoing so root reserves are at risk.

Plants, like animals, also have requirements. Often what is good for an animal is not good for plants, nor the pasture in general. An animal wants to keep a plant eaten down all the time so that there is a much larger percentage of new growth, while a plant needs to be allowed to grow to maintain health.

Animals are not forward thinkers so have to be managed. They will maximise short-term production to the detriment of long-term production. Plants and animals have evolved together and need each other, however carbon flows that are essential for paddock health and production, drop drastically if animals dominate plants.

CONCLUSION

The problem we have to confront is that the way animals select their diet following rain is not consistent with the way nature designed plants to function.

With regard to when it is best to harvest carbon flows, pastures should be rested after rain. In other words, graziers need to be harvesting only the surplus not the means by which a usable surplus is generated.


ALAN LAUDER

WHY RESILIENCE IS IMPORTANT

Australia has one of the most variable climates on earth and extreme weather repeatedly affects the Australian farming sectors. We have always had droughts, floods and heatwaves, however the climate seems to be getting more extreme lately and it seems to be becoming even more variable. Some would suggest it is becoming a bit random, which is worse than being variable, because we need patterns to plan, i.e. when to plant, when to harvest, when to put the bulls and rams out etc.

When anybody talks about adapting to a changing climate, ask them what adaptation means?

The question has to be asked; are we concentrating too much on our response to the changed circumstances (being reactive), instead of trying to reduce the effect/impact of a changing climate (being proactive)?

Successful farmers are the ones who are good at adapting to whatever their circumstances are.

A resilient paddock is one that has the ability to generate enough carbon flows from rain to keep itself functional and productive. Resilience has two components, soil resilience and plant resilience. Plants fail first then the soil fails, i.e. poorly managed plants do not generate enough carbon flows to keep the soil healthy.  

RESILIENCE ABSORBS CHANGE

A resilient paddock provides the capacity to absorb changed circumstances. Fragile ones just collapse, even with small changes. Being able to absorb changes, means they hurt less.

To quote Dr Leonie Pearson, “The alternative of a resilient system is a vulnerable system: when a system loses resilience it becomes precarious, or fragile to change effects, and even small influences can have disastrous effects”

As a season heads from dry towards drought, this is just another form of changing circumstances.

DEFINING RESILIENCE IN A PRACTICAL SENSE

Getting back to basics, resilience is the ability of a paddock to generate carbon flows from any rain that falls, i.e. resilience is the ability to respond to rain. Perhaps the best test of resilience is the ability of paddocks to respond to isolated small falls of rain during a dry period, i.e. slow the arrival of drought.   

 In a broader sense, resilience is the ability of a paddock to turn rain into carbon compounds.

The photo is a perfect example of what two different levels of resilience looks like.

THE DIFFERENT ASPECTS OF PADDOCK RESILIENCE

Paddock resilience has two components, plant resilience and soil resilience. The maintenance of both requires good management of carbon flows.

Resilience also has to be considered in terms of short-term resilience and long term resilience.

The fast moving short-term carbon supplies short-term resilience. On the other hand, the slow moving long-term carbon supplies resilience over time. It protects the long-term survival of the system.

PASTURE RESILIENCE IS PART OF SHORT-TERM RESILIENCE

Allowing more carbon to flow into plants increases their resilience by increasing internal energy reserves for them to call upon. It also increases their root volume, which allows them to access more moisture and nutrients to grow. Both energy reserves and roots are short term carbon.

SOIL RESILIENCE CONSISTS OF BOTH SHORT-TERM AND LONG-TERM RESILIENCE

Allowing carbon to flow into the soil feeds soil life responsible for restructuring the soil to improve infiltration and water holding capacity. It is short-term carbon in carbon flows that feeds soil life.

Organic matter that supplies nutrients to plants is short-term carbon and is part of carbon flows.

Soil humus is long-term carbon. It brings long-term resilience. It helps hold soluble nutrients that would otherwise escape the paddock and end up in waterways. It provides better soil structure which provides spaces for water to be stored. It changes the pH of the soil and so buffers against any toxic elements present.

Long-term soil carbon originates from short-term carbon in the first phase of carbon flows. Thinking longer term, good management of carbon flows is critical to ensure the ongoing replacement of the little bit of longer-term carbon that is always leaving the system and returning to the atmosphere.

SOIL CARBON ON EACH SIDE OF THE FENCE IN THE PHOTO

I quote what a soil scientist who worked for the Federal Department of Climate Change wrote after looking at the photo.

“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 (14 inches) per year.

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)”.

THINKING PAST STOCKS TO FLOWS HAS POSITIVE COMMERCIAL OUTCOMES

The assessment by the soil scientist on the degraded side of the fence provides an important insight into the broader debate around carbon stocks and carbon flows.

The bare side of the fence still has long-term soil carbon, but this stock of long-term carbon on its own could not make the paddock functional. A functional paddock also has to have short term carbon flowing through it, as the other side of the fence demonstrates. 

Apart from positive environmental outcomes such as protecting the Great Barrier Reef, better management of carbon flows to improve resilience also has commercial outcomes.

The unwillingness of the Queensland Department of Agriculture to see logic in including discussion of the carbon flows concept in extension, because of a stocks focus, is costing the Queensland economy about $70 million a year. This figure was arrived at after a leading rangelands scientist, who was frustrated with the Department’s policy position, suggested going onto the Queensland Treasury website to discover the value of sheep and cattle production to the Queensland economy. It is a conservative figure based on sheep and cattle producers achieving a small gain in production, after seeing their paddocks differently.

ADDING MORE PATHWAYS BY WHICH CARBON IS ABLE TO ENTER THE LANDSCAPE

Because resilience relies on carbon flows, there is a need to increase the number of pathways for carbon to enter the paddock i.e. increase the mix of plants to cover all circumstances.

Increasing the number of pathways means carbon can be collected at different tiers while utilising water at different depths.

A production system based on perennials is more resilient than one based on annuals. This is simply because perennials generate more carbon flows over time, especially in marginal years. Only perennial plants can respond to single isolated falls of rain.

At the extreme of the perennial debate are the perennial edible shrubs like leucaena and old man saltbush (shown in the photo) that transfer the use of water further into the future. They grow under adverse conditions. They maintain carbon flows over time because of their deep roots sourcing moisture deeper in the landscape, which is not available to the grasses.

REDUCING THE EFFECT OF DROUGHT RELIES ON BUILDING RESILIENCE

The best response to drought is to increase resilience to reduce its impact so that it arrives later and breaks earlier. This approach has the added advantage of sometimes not entering drought when others are caught.

CONCLUSION

The only time you can increase resilience, is when it rains. This is because good management of carbon flows after rain underpins resilience.

A resilient paddock that is well equipped to produce carbon flows is also one well equipped to better withstand extreme events, be they drought, heat or heavy rain.


ALAN LAUDER

WHERE CARBON RESIDES

At a land management forum I attended a few years ago, a retired scientist commented that from his experience, problems are never solved by reductionist science. He said it was taking a systems approach that solved problems. The point he was making was that you need to be aware of everything that could possibly be influencing the problem you are trying to solve, i.e. you need to understand the big picture.

The flow of carbon through a paddock influences a lot of processes. If the flow falls too low, it causes a multitude of problems. Production and environmental issues can often be rectified by simply changing management to increase carbon flows.

The diagram below shows the earth system with regard to carbon. It is a great diagram because it puts everything into perspective. The amount of carbon on this planet is finite but some is always moving. It is interesting to know where all the carbon is, given different discussions focus on different pools and the flow of carbon between them.

Earth carbon pools and the flows between the pools (1 Giga tonne = 1,000,000,000 tonnes)

The first surprise for most of us is that the oceans contain 67% of the carbon on earth. Also, there is a lot more carbon flowing backwards and forwards between the oceans and the atmosphere than there is between the land and the atmosphere.

The atmosphere only has 1.3% of all the carbon on earth, which explains why it is easy to drastically alter its carbon content given the magnitude of the flows going on.

THINKING PAST CARBON STOCKS

The diagram includes both stocks and flows, which is a good starting point for shifting our mindset past just thinking stocks and measurement. It helps us appreciate that flows are an integral part of the system.  

he diagram includes both stocks and flows, which is a good starting point for shifting our mindset past just thinking stocks and measurement. It helps us appreciate that flows are an integral part of the system.  

Think of your grazing paddock as a sub system within the earth carbon system. All life on this planet is carbon based. So, in order to exist, your cattle, grass and soil life are all relying on the atmosphere as a source of carbon atoms. All agriculture produces and sells carbon based products, i.e. all agriculture sells something that was living.

A grazing paddock is a dynamic system, not a static one. Thinking carbon flows is to take a dynamic approach while thinking carbon stocks is to take a static approach.

WHAT FLOWING CARBON IN A PADDOCK LOOKS LIKE

The picture below reminds us that we have to keep short term carbon flowing through the paddock to remain in production. 

Carbon is the main building block of everything living, be it cattle, grass or soil life and carries the energy that all three require.

SOMETIMES THE MAIN FOCUS IS LONG TERM CARBON, SOMETIMES SHORT TERM CARBON

Climate change policy has a focus on long term carbon and measuring, however the decisions graziers/ranchers make relate to short term carbon as part of managing carbon flows.

The diagram suggests that of the 62 Giga tonnes coming down from the atmosphere, most of it returns to the atmosphere again. Carbon trading is focused on the 2 Giga tonnes that stays above and below ground while producers are harvesting some of the 60 Giga tonnes that is flowing through the paddock. 

THE CARBON FLOWS CONCEPT  

The carbon flows concept, that is the basis of this column, discusses the role of carbon as it keeps moving through the paddock, above and below ground, including through livestock. The concept explains what carbon does as it moves and the processes it activates, before returning to the atmosphere. It highlights that carbon is the organiser as it flows through the landscape. It discusses the different speeds of carbon as part of increasing profits and reducing the production of methane per kg of production. The concept is not dismissing the importance of long term soil carbon, instead it is suggesting that because long term carbon is hardly moving, it is only about 2% of flowing carbon.

The carbon flows concept should not be confused with discussion of the carbon cycle diagram.The carbon cycle diagram is a one dimensional discussion. It goes no further than saying that carbon cycles. It simply discusses the different pools carbon moves between.   

The carbon flows concept discussed in this column is a systems approach.

EXPANDING THE DEBATE

When extension focuses on just carbon stocks and measurement, this is a form of reductionist science as the focus is too narrow. The purpose of this column is to broaden the debate. 

It is only natural that past producers like myself want to help current producers. The seasons lately seem to be harder to deal with, hence the need for more knowledge. The catalyst for me to write this column was my failure over many years to have any influence on the policy of the Department of Agriculture in my home state of Queensland, even after presenting a logical case to those at the top. To this day the Department still has a policy focused on stocks and measurement, not flows.

Not a long time ago while giving a presentation on carbon flows, I was again reminded of Departmental policy. About ten minutes into the presentation, an extension officer of the Department interjected with the comment, “Maybe I am stupid, but none of this is making any sense to me”. I thought to myself, he wouldn’t have made that comment if his Department had a different policy. Then another Departmental extension officer joined in with the comment, “Look, we have been measuring carbon and it is not changing”. The comment did provide an opportunity to explain the difference between stocks and flows in another way. My response, “Well, if you can’t measure a change in the stocks, then all the carbon has to be in the flows. You have just confirmed the thrust of what I am saying”.

CONCLUSION

With any production or environmental problem you are trying to solve, part of the solution will be improving carbon flows into the paddock. Protecting the Great Barrier Reef is a perfect example.

Carbon stocks are the outcome of carbon flows, be they short term or long term. This highlights that discussing carbon flows is the entry point of any discussion around the role of carbon in the paddock, in fact even carbon trading.

Being too focused on stocks and measurement is a good example of reductionist thinking.

Because rural producers sell carbon based products, their day job is recycling carbon. The more carbon that flows, the more they have to sell.

With carbon flows, once you visualise the flows in a paddock, the dynamics of the whole system and how it functions becomes clearer.


ALAN LAUDER

PRACTICAL FACTS THAT PROVIDE UNDERSTANDING

Did you know that if we compressed the atmosphere and turned it into liquid, then the oceans would be 500 times bigger? This reminds us that we perceive things the way we think.

What actually happens in the paddock can at times be very different to our perceptions. Take the case of root growth with grasses. When livestock over consume the leaves of grasses, while they are trying to grow after rain, some would assume that this is just reducing potential ground cover. Even amongst those who are aware that there is a relationship between root growth and grazing pressure, they still may not be aware that there is a tipping point after which leaf removal can suddenly have really adverse outcomes for root growth.

The effect leaf removal has on root growth

It is so easy for us to forget that plants make decisions just like we do. It is now well known that plants send out chemical instructions to activate soil microbes to get them to do what they need done. The graph above highlights that plants also make decisions around allocation of incoming carbon (remembering that roots are 45% carbon). Plants are not stupid, so we have to assume that they do understand the importance of roots, however when leaves start to be excessively over eaten by animals, they place a higher priority on replacing leaves. This is logical as leaves are the entry point of carbon and energy.

THE WATER HOLDING CAPACITY OF ORGANIC MATTER

There is no substitute for going back to the basics to get things into perspective. When running a grazing business, there is a price to be paid for not letting plants generate carbon flows to their full potential.  Thinking about the carbon that ends up in the soil, a 1% increase in soil organic carbon means the soil can hold an extra 144,000 litres per ha (2.5 acres). Organic matter can hold 5 times its weight in water.

THE ENERGY IN ORGANIC MATTER

Just as modern society is reliant on energy, the health of paddocks and their productive capacity are driven by available energy. It is carbon that carries energy. Sheep and cattle rely on the stored energy in grass and, soil life also relies on the energy brought in by plants. Researchers in England discovered that an acre (0.4 ha) of soil with 4% organic matter contains as much theoretical combustible energy as 20-25 tonnes of anthracite coal. Another researcher in Maine, US, equated the energy in that amount of organic matter to 4,000 gallons of fuel oil.

CONCLUSION

We have all heard the saying, “Perceptions are stronger than the truth”. However, with land management, facts are better than perceptions.

Having understanding is the basis of good management.


ALAN LAUDER

WET YEARS ARE OVER EMPHASISED FOR REGENERATION

Thinking a wet period on its own can improve a paddock’s productive capacity and resilience is like thinking a runner can win a race without adequate preparation. To understand the true driver of paddock regeneration it is what you do in the average years that matters just as much as the wet years.

The foreground had a deficiency of carbon above and below ground prior to the wet period, so hardly regenerated

Thinking a wet period on its own can improve a paddock’s productive capacity and resilience is like thinking a runner can win a race without adequate preparation. To understand the true driver of paddock regeneration it is what you do in the average years that matters just as much as the wet years. 

How successful wet periods are at regenerating paddocks is determined by how well carbon flows have been managed in the lead up-years.

Wet periods can either fast forward all the good work you have been doing in average years, or if you have been a poor manager of carbon flows, then when the wet period has ended, you can find yourself in the same position you were in before it started.

It is carbon flows over time that prepare the soil to allow better germination and establishment of perennial grasses. This is because carbon flows generated by plants, feed the soil life that are responsible for restructuring the soil and making it more fertile. Poorly managed plants only generate small flows of carbon, which means soil life is limited in what it can do.

If a paddock is degraded, then plants can struggle to establish, even in good seasons.

The photo above is of a paddock that was locked up for 15 months during a period of above average rainfall. It shows that wet periods are more successful at regenerating better functioning areas. The area in the foreground, reinforces that what wet periods can achieve is highly dependent on the state of the landscape prior to the favourable rain.

The 15 months rest was able to regenerate a lot of the paddock, but not change the area in the foreground, where carbon flows had fallen too low over time. The next photos are close ups.

Close up of where we are standing in the above picture

Where we are standing, the greener grass is the productive paspalum. It re -entered the landscape following rest, while in the foreground of the first photo, only useless galvanised burr is growing.

The rest period had sufficient rain for regeneration of grass from seed on several occasions, yet the area in the foreground was not able to respond. There was little water infiltration in this area and the soil was not able to maintain moisture on the surface long enough to allow germination. Little ground cover, to keep the wind and sun off the soil, was another issue limiting germination.

Close up of the area that didn’t respond to the wet period

THE ROLE OF WEEDS

Think of weeds as nature’s repair agent. When paddocks start to degrade, nature sends in weeds as an alternative way to generate some carbon flows. The blue galvanised burr in the foreground of the first photo, is playing this role. We all know that when the perennial grasses come back, the weed population immediately drops.

WHY WET PERIODS CAN BE MISLEADING

Wet years can be very deceiving. There is often a good coverage of pasture and it looks like the paddock has regenerated. But has it? Look closer, and a lot of the ground cover is annuals, which will disappear when the rain stops. The fact water keeps arriving in wet periods and has more opportunities to soak in, masks the reality that the soil condition has not changed. This is not to discount the value of the extra plant carbon that is introduced into the paddock by the short term prolific growth. This plant carbon could be the beginning of soil improvement if management changes and starts to focus on improving carbon flows.

What extra plants remain long-term when the wet period has ended, is the true test of what has been achieved.

MAINTAINING A SEED BASE

Regeneration of perennials relies on an adequate seed base, which is why resting after rain in average seasons is critical. 

There is not enough time in a wet period to produce the necessary seed, then see it germinate, and finally, see seedlings establish.   

CONCLUSION

If there are not more perennials after the completion of the wet period, then little has been achieved. Naturally, this comment does not apply to pastures in very good condition that had already achieved the maximum possible coverage of perennials. 

The “so called” average years are really part of the regeneration process. Good management is ongoingThis is why I feel uncomfortable when somebody suggests that all we need is a wet season to undo degradation.


ALAN LAUDER