Agricultural Land Condition

From time to time, very useful work is done by goverrnment agencies, and the
Report On The Condition Of Agricultural Land is no exception.

Released in December 2004, and branded as "Report No 1", the Report is a long overdue assessment of the natural capital of the agricultural lands of the state. The Foreword by the state government's Minister for Environment and Conservation of the day John Hill, says ... "Our ancient and delicate landscapes have been subjected to periods of extreme degradation" with "less dramatic forms" being "dryland salinity, soil acidity and the loss of perennial vegetation cover, with its associated native biodiversity."

The results of this baseline study give cause for great concern, unless of course a plan of action has been subsequently developed and is being implemented. The concerns are founded in what appears to be continual decline in the natural resources base as it exists now. This decline has been suspected for decades, and yet what action for arrest, recover, and restore have taken place? 

There is little evidence that an integrated plan exists.

Let's examine the main elements of the Report.

There are 10.2 million hectares of land used for farming in South Australia. This land has been cleared of its native vegetation and almost all of it has suffered some form of degradation as a result of farming systems that are inadequately aligned with sustainability requirements of its natural resources. Loss of productive capacity of agricultural soils results in adverse environmental, economic and social impacts, many of which are effectively irreversible.

It's important to remind ourselves the area of the state that is under examination. In the map below, it is the land represented in pink (dryland agriculture) and red (irrigated agriculture), and  interspersed with livestock grazing land. We are referring to the southern parts of the state that have higher rainfall.

sa map

Map Ref:

What is the area of agricultural land? The Report contains two figures - 10.2 million hectares, and 15 million hectares (ref "Revegetation", pg. 68). This latter figure may include some outlying sheep grazing areas on the fringe of the cropping regions. The Report states ...

"Of the 15 million hectares of land in the agricultural districts of South Australia, only around 3.2 million ha (21%) remain under remnant native vegetation."

This statement implies that 11.8 million ha have been cleared. Whatever the true figure is, it is a certainty that the agricultural areas represent just 15% of the state's area, and of that 15% most has been cleared of native vegetation. 

Farming System Instability

Because of the ancient landscapes and their relatively infertile soils, farming systems require high and persistent inputs of energy, materials (e.g. fertilisers, lime, weedicides, herbicieds, and other sprays) and human endeavour. The farming system is human-controlled of course, but is influenced greatly by outside, or external, factors such as weather, pests, prices, commodity demand, global influences, to name a few. These systems however, consume non-renewable resources, and as stated in the Report (pg 20) "are inherently unstable".

Here lies the conundrum. Although these farming systems deliver the outputs (i.e. crops and fibre) to the market economy, and create wealth to individuals, corporations, and the state, they are operating in an unstable state. To accept a continuance of this situation is dangerous, and foolhardy. 

At some point in time, this instability will reach a critical zone from which recovery to a stable state of the landscape and ecosystems within it, will not be available. What will happen is that a new stability harmonised with a modified environment, will be reached, and it will not be entirely as a result of the original influences that caused the instability in the first place. The system at greatest risk therefore, will be present-day farming. 

Those involved in agricultural and horticultural systems require and seek stability of every component that affects farm output. It is rare that all components are in synchronicity in a farming system annual cycle, but if most are in step with each other, then high financial returns are likely to result. 

If one component fluctuates significantly (just think rainfall), then greater intervention (i.e. inputs) is required to achieve a relatively stable system output.
If the component soil adopts a different state (think dryland salinity), then it will be only a matter of time, perhaps following a sequence of "corrective" interventions to maintain productivity (i.e. system stability), before the response of the soil fails to meet the criteria required of the farming system.

It is a natural principle ... 

"Nature cannot withstand a systematic deterioration of its capacity for renewal ..."

One of four systems conditions in Karl-Henrick Robert's 'Educating the Nation: The Natural Step'

If the beginnings of instability are not checked and the system is not recalibrated to a "natural" state, or to a state that harmonises farming and the environment in which it operates, then sustainability in all its forms (i.e. ecological, economic, and social) will suffer. The greatest threat of all would be collapse of the agricultural system.

Let's now see what the Report contains.

Report Results

The following information has been extracted from the Report. Now, keep in mind that the report is of conditions back in 2004.

  • About 781,000 hectares have a moderate to high inherent susceptibility to water erosion by virtue of soil type and land slope.
  • About 2.4 million hectares have a moderate to high susceptibility to wind erosion, and 3.5 million ha have a moderate to low susceptibility, "but which can be at risk during extreme rainfall events"
  • “At least 1.9 million hectares ... is either already in a degraded state due to acidity, or is on the brink of damage due to acidification.” Agriculture accelerates the acidification process and results in productivity decline.
  • About "879,000 hectares of land in the State has a very low topsoil pH" - these soils are naturally acidic. Lime is introduced to raise the pH. 
  • There is currently 729,000 hectares of saline land in the State and "without intervention, by 2050 the area of saline land could exceed an estimated 900,000 ha".
  • “The area of land directly affected by water-table induced secondary salinity in the agricultural and remnant native vegetation areas of the state is estimated to be around 398,000 ha. This is predicted to increase to about 593,000 ha in the next 20-50 years, with most of the increase on the coastal plain of the Mid and Upper South East.” 
  • “Almost 1.7 million hectares...have soils with physical properties that make them inherently susceptible to soil surface structure breakdown.” 
  • “The majority of South Australian soils have very low natural phosphorus levels, and often have trace element deficiencies. Without very large inputs of key nutrients, agricultural productivity would be very low.” 
  • “There are about 2.48 million hectares ... that are moderately to severely affected by water repellence.” 
  • During the assessment period of the Report, the rate of revegetation of native species for non-commercial purposes was about 4,000 ha annually, and for native non-indigenous species was 400 - 1,000 ha annually. Blue gum plantations in the South-East and other small-scale agroforestry plantations (mainly in Mt Lofty Ranges) increased the annual revegetation rate. 
  • "It will take many decades of revegetation at this rate to have a significant impact on major NRM issues like dryland salinity, soil erosion or native habitat restoration.” The desirable native revegetation rate should be 20,000 - 50,000 ha/year.


Has the farming system in the agricultural lands of the state reached a threshold of permanent instability? Has it crossed it?

These results are approaching 10 years or more of age, and there does not appear to be similar information available for the present time (2011). It is most likely that there has not been a reduction of the various impacts, and so on the face of it, they should be cause for great concern. Connect the results with the predictions that South Australia will experience a 1 - 6 deg.C increase in mean temperature by 2070 (ref "No Species Loss Strategy"), and a concomitant 25-30% decline in rainfall (mostly Winter and Spring rainfalls) in the agricultural areas, then the cause for alarm should be further heightened. Add the following disturbing statement from the No Species Loss Strategy Overview, and then make your own conclusion.

The loss of South Australia’s native plant and animal species since the arrival of European settlers is alarming. At least 23 mammals, 2 birds and 26 plants have already gone forever. Our State’s extinction rate is one of the highest in Australia. 

Today about one-quarter (over 1000 species) of all terrestrial vascular plants and vertebrate animals in South Australia are considered to be threatened – 63% of our mammals and 22% of our vascular plants are formally listed as threatened at the State level. Our ecological communities are also threatened. 

Despite sustained hard work by professionals, landholders and volunteers alike over many years, the decline continues. Clearly we need to work smarter and learn from our mistakes and successes, and we need to do this with a sense of urgency if we are to clear our extinction debt. 

Native biodiversity within South Australia is in decline, yet relatively few threatened species and ecological communities are being managed for recovery. 

The threat is real and present for terrestrial, aquatic and marine ecosystems. We can no longer modify habitat, fragment ecological communities and populations, introduce invasive species, and alter environmental water flows and fire regimes. Climate change is now adding further challenges and often unknown complexity to how we might manage current threats, and restore ecosystems in the future. 

Instead we must intervene with serious planning, innovation and endeavour. 

In Landscape Change I described what should be done to arrest any further decline in natural capital in the state. 

And in a Submission on Managing Soils some further information has been described on the seriousness of agricultural land in South Australia.



If further evidence is needed of the dire consequences confronting South Australia, go now to Climate.

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