The Big Four:

Basic lessons about our environment

Mary Maclean, Armidale, NSW

 
Environmental literacy, the ability to read the environment, is essential for the survival of civilisation. It is as important as learning to read and should be taught in primary school. If we don’t increase environmental literacy our ecosystem will continue to deteriorate.  It could be taught in primary school.

 My vision is that the majority of children would have, by the age of twelve, the ability to diagnose ecosystem malfunction and treat the problem, or even better, be able to avoid the problem in the first place.

 I think of environmental literacy as a working knowledge of “The big Four”.  These are the four major ecosystem processes described so well by Allan Savory in his book “Holistic Management A New Framework for Decision Making” Island Press, 1999.  His ground breaking work on decision making, Holistic goal setting and grazing, often overshadow his ability to pull together known knowledge and make us realise its importance.

 So this is a revision lesson, with practical examples, in an attempt to emphasise the importance of what could be essential knowledge for primary school children, with a concomitant large and positive impact on the environment.

 The four main processes that have to function effectively in any landscape are entirely interdependent, but are easier to understand if described separately.

 
Water Cycle

The first is the water cycle.  There is a fixed amount of water on earth, which cycles in liquid, frozen or vaporous form from deep below the surface of the soil to high into the atmosphere.  All living things need water.  Most of it is in the oceans and is saline.  Over much of Australia we have a chronic shortage of water, so we can ill afford to waste a drop.  Drought is ubiquitous, however we are still caught unprepared each time it arrives.

  Water is needed to grow the green plants which feed us, or feed the animals that we eat.  The condition of the soil is vital to the effective use of water.  It is well understood in agriculture, but perhaps not in the wider community, that soil covered with growing plants and decaying litter will absorb more water where it is needed to help the growth of these green plants.  Water is also needed to help sustain the billions of microscopic bacteria and fungi that are, or should be, in the soil and which are vital to plant health. These biota make nutrients available for plant growth.

  Effective & ineffective water cycle

With an effective water cycle rain percolates through the surface layers of the soil and is used by the soil biota and the plant roots.  Some water percolates further down and recharges the underground water supplies, finally re-emerging in gullies and springs or remaining deep under the earth in sub-artesian basins.  Plants take up water and it is transpired into the atmosphere.  Some surface water evaporates.  Some runs over the surface and ends up in the waterways.  Transpired and evaporated water re-forms into clouds.  The cycle continues.

  Now we can begin to tease out the problems that are caused by a faulty water cycle.  Lack of ground cover in the form of plants and litter means increasing runoff, soil lacks its vital water supply and washes away with the water, causing loss of topsoil, important nutrients and organic particles.  Streams become polluted, silt settles on the stream bed and aquatic life suffers.  Pollutants can be washed into streams unnecessarily.  Droughts will be more frequent and more severe.  Windstorms will take topsoil if it is exposed.

  Soil loss

Why do we accept soil loss as a fact of life?  Almost all agricultural practices cause soil loss (many tons per hectare annually) with enormous cost, both environmentally, economically and ultimately socially.  As I write, there is a huge dust cloud over the major part of eastern Australia and a professor on the television tonight stated that droughts cause soil loss.

  This reinforces the myth that people are not responsible for the lack of ground cover during drought.  Largely, people are responsible.  Soil loss causes civilisations to die and deserts to form.  In Australia we already have four large deserts, the Great Victorian being the fourth largest in the world, and we are losing good topsoil at an alarming rate on our remaining productive land, even in good years.  This does not have to happen.  Droughts are no excuse.

  Ground cover

Consider the grass cover that survives on roadsides during drought.  If we maintain good ground cover, the water cycle will be more effective, we will grow more pasture to feed more animals, erosion will be absent, streams will run clear and unpolluted.  In fact, we must start actually rebuilding our soils by building up organic matter.

 At the very least we must return them to the spongy fertile soils documented by some of our early explorers and settlers.  Eric Rolls, in his recently published “Visions of Australia: Impressions of the Landscape 1642 – 1910 ” (2002), mentions one early explorer amazed at the depth of organically rich soil on a very steep slope, soft enough to deeply bury the butt of his carbine.

  Mineral Cycle

The second of the Big Four is the mineral cycle. This is perhaps even more complex than the water cycle.  Minerals cycle from the atmosphere, which contains nearly eighty percent nitrogen, and from decaying plant material at the soil surface. Our microscopic friends in the soil make minerals from the air, water and soils, available to the plants.  As animals, including humans, consume the plants, the minerals go too.

 Higher up the food chain where animals eat meat, the minerals are again passed on.  Death and decay return the minerals to the soil.  Decaying plants can return minerals to the soil for re-use, but minerals can be lost to the atmosphere, such as when plants oxidise rather than decay as litter.  Oxidising plants tend to be grey in colour rather than pale yellow.

 Next time you cast your eye over the landscape watch for signs of oxidisation.  Healthy grasslands will have a yellow or red tinge as they mature from green growth.  Grasslands with old oxidising leaves and stems will have a grey tinge overall.

 Animals need to be part of most landscapes.  Plants evolved in the company of animals.  Animals help recycle nutrients back to the soil as they either trample or consume the plant material, thus keeping the plants green and healthy, rather than old and oxidising.  The animal’s excreta is also an efficient mineral recycling product.  Recent research by the NSW Agriculture at Trangie Research Station, found that pastures where grazing animals were excluded deteriorated over time.  The researchers were surprised by this result.  This finding is of particular significance to land managers who are caring for and conserving our National Parks, and will need careful, creative consideration into the future.  Animals can also degrade the landscape, depending on how they are used and the time they are there.

  Energy Cycle

Number three is the energy cycle.  Our sun provides endless free energy.  Green plants convert this energy into a useable form through photosynthesis and this energy is passed up through the food chain the same way as the minerals.  Some energy is lost on the way with the production of heat.  Wise farmers will maximise the production of energy, and thus their profit, by maintaining green pasture for their stock for as long as possible each year.  Edible green leaves are money in the bank for graziers, and there are environmental benefits.

  Biological Community

The biological community is the last of the Big Four to consider.  It is closely linked to the functioning of the first three.  In fact, the first three will not function at all without life, or a living biological community. 

 We need as diverse a biological community as possible, above and below the soil level.  Biodiversity is vitally important.  Monocultures, such as single species crops, do not encourage biodiversity.  In fact they become virtual biological deserts, opening the way to weed, pest and other problems.

 Nature is always trying to diversify and will react in ways unintended when monocultures are encouraged.  Pasture Cropping is a new method of cropping into established perennial pastures and it should soon be possible to maintain a biodiverse ecosystem in cropped areas.

 If you have planted trees recently in a rural setting and have excluded stock, keep a close watch on the surrounding grasses.  Over time, perhaps years, you may notice a tendency for the number of grass species to fall, the grasses may become more senescent, less green and have increasing grey, oxidising leaf material.  There may be more bare ground around the increasingly clumpy grasses.  All are indications of problems with the Big Four.

 The water cycle will become less effective leading to soil loss and biodiversity loss.  The minerals will cycle less, aiding this biodiversity loss.  The energy cycle will be less effective dure to the presence of less green plant material.

  Judicious introduction of stock can reverse this process.  It needs to be high impact, short duration stocking, with long recovery periods for plants.  This means lots of stock for perhaps only hours rather than days, followed by up to six months rest, depending on the rate of growth of the grasses.  (Less rest when the grasses are growing fast).

  Non-rural dwellers

Creative urban dwellers can improve ecosystem function in their environment.  Does the rain that falls in the cities and towns reach the soil or will it end up running over impervious surfaces, causing flooding and heartache?  How much of our roof water is used on our gardens and in our toilets as grey water?  Can we have more porous surfaces?  Do we really need solid concrete driveways and footpaths or can we use more porous material?

 Urban dwellers with gardens can improve the functioning of the Big Four in their gardens.  The trend in garden design is for minimum species diversity and maximum artistic impact.  More biodiversity would be a useful trend to encourage.  Exotic berry bushes can be beautiful, but are known to cause an explosion of currawongs who deplete the small native birds that we love in our gardens and reduce the variety of birds in the urban environment.  There are many similar examples that environmentally literate citizens might consider.

  Travelling Stock Routes

There are hundreds of thousands of hectares that make up our travelling stock routes and stock reserves.  The intermittent grazing that these areas have traditionally experienced has left them in quite good condition, and many have been identified as significant refuges for native plant and animal life. However some of these areas have not been grazed judiciously and are now in poor shape.

 Citizens might lobby those responsible for their care when management decisions are being made.  These areas are running at a financial loss of public money at present.  It has been suggested that drovers be employed to move stock through the Long Paddock, while ensuring adequate recovery periods for the grasses between grazing. 

 The result would be rejuvenated grasses, increasing biodiversity, improving water, mineral and energy cycles.  Maintenance costs might be reduced and stock could be sold for profit.  As biodiversity is increased weeds would be reduced.  A similar regime might reverse the soil loss problems in our city water catchments.

 A recent article in the Sydney Morning Herald tells of Sydney’s water supply dams silting up.  Deterioration of the Big Four in the catchment area should be preventable.  This problem is not unique to Sydney, but the Sydney Catchment Authority’s general manager is quoted as saying “Sedimentation is a natural part of the operation of any dam”.  It doesn’t have to be this way.

  Read the environment

Everything we do will impact upon the environment.  Impacts due to our highly technological civilisation need tempering with basic environmental sensitivity.  Consider the impact on the Big Four before taking action or when remediation is necessary.

 Nurture rather than force into submission.  Read the environment.  And most important of all let us teach our children how to read the environment by giving them a working knowledge of the magical Big Four.

 It is you and I that need to make some thoughtful change.  Do we have the courage?

Good luck!

Editor’s note:   Perhaps this is a good time to review Part IV of “Holistic Management A New Framework for Decision Making” by Allan Savory and Jody Butterfield (Island Press 1999)  Chapters 11 – 15 are easy to read, with some excellent illustrations and examples.