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.
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.
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.