The Oz farm in 2020?

Tractor in field

ROSEMARY and Bill watched the huge tanker crunch down the driveway with a full load, just missing the smart white gateposts.

"Jeez," Bill observed. "We got more for this season's water than we did for the ruddy wheat crop."

"And more per litre than Dad used to get for his milk," Rosie replied.

No doubt about it, the water harvest was a paying proposition. That extra bit of annual precipitation courtesy of the Greenhouse Effect hadn' t hurt either.

These days, water paid better than trees, and you could still make a reasonable quid out of planting those to soak up the CO,.

Not that Rosie and Bill needed much incentive in that direction. Their trees were producing everything from pharmaceuticals, health foods and bush tucker to essential oils, flowers, violins, fuel , furniture and cattle fodder.

And seeds. The global market for tree seeds was on a roll, as nations struggled to repair the devastation of generations. They were direct-selling hundreds of kilos round the world on the Internet.

Trees weren't just a crop, either. They were a keystone of the management plan, a plan that aimed to recreate something that had totally vanished over a century earlier - the way soil, water, nutrients and landscape functioned before any human ever set foot on the continent.

Rosie had done a lot of research into what their land had been like more than 100,000 years ago, before European settlement cleared the trees and dammed the rivers. Even before Aboriginal settlement brought fire management. She reckoned Australia had spent 60 million years or so evolving its soils and water systems and developing its specialised plants and animals, so there must be an ideal natural balance there, somewhere.

A real Australian farm was one that obeyed what the continent decreed - yet still produced the valuable food, fibre, timber and other products to meet human needs. That was their philosophy.

The secret lay in controlling the flows of three things - water, nutrients and carbon. Managing the farming system so that none of them leaked away, to create problems like salinity, infertility or nutrient pollution. And keeping the cycle as free of pests and artificial chemicals as possible.

In a new twist, it also meant paying close attention to the farm's most precious livestock - the billions of microbes in every handful of fertile soil that governed fertility, plant growth and disease. The art of managing the "bug flock" for optimum crop or tree yield was a novel and exciting challenge, which they had delegated to their daughter, Clare, who was just completing her microbiology degree. She was the only one who could pronounce the names.

While the farm still grew annual crops of grains and legumes, it did so in a much more opportunistic way, matching the crop to the moisture content of the soil. The phases of crop and deep-rooted pasture were carefully judged to limit the leakage of excess water into the watertable. Bill often sowed his cereal crop directly into a perennial forage or pasture crop to control this subsoil leakage. Although his acreage was much reduced, gene technology and the new precision farming techniques had done wonders for the yield. Not wishing to see precious fertiliser dollars flushed down the creek to pollute the local wetland, he monitored his nutrient use and soil fertility constantly, using leaf-sampling, benign microbes, foliar feeds and other strategies to apply just as much as the crop required, at the right time. A smart new CSIRO computer program helped him to model the outcomes of different strategies.

Half the total land area of the farm was now trees - trees on ridges and slopes, trees in belts and along intercept banks, trees in blocks, lining the river, and salttolerant trees and shrubs gradually encroaching on saline scalds. All pumping water like mad.

Even so, Rosie pointed out, the remaining half of the farm was still using only half the water that fell on it from heaven. A network of intelligent sensors told them exactly how much water was slipping past the root zone, and where. So they'd developed a system of contour banks, channels and deep drainage to harvest every drop. Some they injected into a big underground 'dam' (a natural aquifer) for summer irrigation of highvalue horticultural crops. Some they released along the creek in accord with its natural seasonal flow. The rest they channelled through a wetland to cleanse it and then sold it to a private water-bottling firm for an unheard-of price. They'd seen it, in smart blue bottles, retailing in restaurants for almost the price of a cheap cask wine. To Bill it was still swampwater, but if the punters didn't mind, nor did he.

The key to the water story was that they weren' t managing their farm alone. Together with the II other landholders in the catchment, they'd formed a consortium to manage the local eco-resources, including making sure there was water for the local river to resume its original annual cycle of shallow flood and drying out to a chain of ponds. It had begun as cooperation to develop wildlife corridors and streambank revegetation, and had gone on from there. There was now a respectable income from the government, which had at long last taken to paying farmers for the water they set aside for environmental purposes, as a public good. As a profitable sideline, the group was now exporting sustainable farming advice, technology, seeds and genes around the world on the web.

The water story was echoed in the electricity from the six big generating fans on the hill-slopes, which they sold into the local grid. A CSIRO computer had revealed they had a ' wind-mine' prevailing wind patterns and slopes of a particular shape better suited to generating energy than some strips of coastline.

Part of the water management allowed the farm to pump water into up-slope dams, then release it down a turbine when GUEST SPOT electricity demand was peaking. To be in the power market you had to deliver when everyone had their air-conditioners on, not when the wind blew. The farm PC studied the market day and night, selling when the price was right.

One of the keys to the success of the farm was biotechnology. Once consumers had recognised the benefits, Rosie and Bill, like other farmers, had been able to use transformed crops and trees to almost eliminate the artificial chemicals of yesteryear and lower their fertiliser inputs. Of especial value were the new grain crops, incorporating genes from Australian native species for drought- and pestresistance, salt-tolerance and enhanced nutritional profile.

Many of these new grains were now incorporated in the 'wonder foods' , the revolutionary diet that was starting to slash national death rates in the Australian population from heart disease, diabetes and cancer. Salinity was still there, a lurking menace, just below the ground. But since the local mining company had taken to harvesting the salts for use in the extraction of valuable substances like titanium, zirconium and other industrial products, it was now more of a boost to the local economy than a threat.

Rosie and Bill knew salinity would still be a factor when Clare's great-grandkids had the place: winding back the damage of years gone by would take generations, even centuries.

But it was also salinity whose deadly warning had prompted the momentous change to a truly Australian farming system. It was salinity that showed scientists and landholders how the continent really worked, and so unleashed a raft of new management systems, industries and know-how exports. Salinity, Rosie reflected. Where would we be without it?