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In his book Back from the Brink: How Australia's landscape can be saved*, Peter Andrews lightly unfolds an epic story of how the Australian landscape evolved and functions. The main story starts by observing a link between the health of his horses and pasture weeds and is about understanding Australia's climate, water-table, soil processes and, the king-pin, biodiversity. It is an environmental detective story that unearths the reasons for the almost ubiquitous, non-stop deterioration of farms and rangelands across the country. His observations, experiments and deductions resonate as good old-fashioned natural history: how he has "read the environment" and, with historical depth added, arrived at conservation - with further help from his horses. In essence, he finds that ever since Australia broke away from the Antarctic it has been wet, with extensive marshes and wide floodplains. This is despite always having had little rainfall due to its flatness. In these unique conditions, plants evolved to manage the available water. How did they do it? By minimising both evaporation and run-off to the sea. Working in consort, a functional trilogy of plant types - trees, grasses and weeds - evolved to reshape the landscape, manage soil fertility and surface salinity, and maximise biodiversity. Andrews is convinced that plants optimise overall growth and productivity. Then people arrived. Unable to understand how the unique Australian ecology worked, they took to burning to assist hunting and imported hard-hoofed animals to be grazed. The land deteriorated, almost from day one, but farmers prospered. In recent decades the deterioration has progressed continent-wide, and is now crippling productivity, but still farmers have failed to adapt their methods: they just try harder. Destruction of farm lands is a worldwide human story. A part of the problem is traditional attitudes. Up to now, Andrews has faced farmer, official and scientific scepticism with little support. Yet his brilliant insights offer a last chance at true sustainability. But where are the soil conservation managers? Andrews gives this job fairly and squarely back to the plants. The original Eden is out of reach, but now with a degraded environment the plants need some initial help. The farmers' part, if they will, is to reverse all the main ad hoc (European) agricultural methods, he argues persuasively: Australia needs to stop irrigating, ploughing and draining land and to end herbicide and fertiliser use. He maintains that doing this could be to the farmers' economic advantage, even within just a few years - if they grasp the nettle firmly - and accept the huge cash savings. He has revitalised land this way. The formula: each package of land within a farm should consist of trees and shrubs on high ground; these protect the high-end of the water-table. The trees attract rain and fertility which seeps down to the main cropping area; typically this grows grass but needs mulching to sustain cropping. Importantly, leave the lowest land fallow. When weeds grow, anywhere, encourage them and mulch them. Remember to trust and learn from the plants as Andrews has. In today's highly stressed conditions, some imported plants, including willows and thistles, can play a useful role, out-performing natives. I believe that what Andrews advocates for Australia has relevance elsewhere. For example, much of New Zealand is clearly farming on an imported trajectory towards ecological breakdown while dreaming of ever higher exports. The driving force in the ancient ecology was the active fertilisation of the soil and forests by minerals from the droppings of billions of seabirds. It's a different model to Australia, with some overlapping principles. Is Aotearoa similarly at risk? The key danger signals are dependency on bag fertiliser and irrigation. If you don't want the mainstay of our future to be artificial hydroponics with no wild biodiversity, then it is time to take a leaf from Andrew's book - and use more horse sense than inappropriate tradition. *Back from the Brink: How Australia's landscape can be saved, by Peter Andrews, ABC Books, 2006 • by Dr Cedric Woods, a Dunedin ecologist. |
