IT MAY take a decade to rebuild Australia’s capability in the soil sciences, but it should be a matter of urgency in the face of a global food crunch, a leading soil scientist says.
CSIRO’s Land and Water Division chief, Dr Neil McKenzie, told the 19th World Congress of Soil Science in Brisbane this week that maintaining the health of our soils is of global importance.
“Whenever we’re talking about food security, we have to take a global view,” Dr McKenzie said.
“Three hundred years ago, if your village ran down its soils you were in trouble; you lost your food supply and perished.”
“Now, the land and water to support a global citizen are scattered all over the planet. Soil degradation and lost production are not just local or national issues.”
Australia’s agricultural sector currently feeds an estimated 60 million people. Any loss of production is felt in other countries, which then put pressure on other areas to supply the shortfall.
Population growth curves indicate that global food production will have to increase 75 per cent by 2050, in the face of finite arable land, yield plateaus, less oil, nutrients and water, diminishing biodiversity and climate change.
Addressing that challenge will require healthy soils - but Dr McKenzie said Australia’s scientific capabilities in this area have been run down in the past 15 to 20 years, as successive governments cut funding for agricultural research.
Rebuilding capability will take at least a decade, Dr McKenzie said: the time needed for future soil scientists to undertake undergraduate and postgraduate degrees, and get several years of practical experience.
The story of Australian agriculture revolves around science.
For the first 100 years of agriculture here, yields progressively declined on soil exhaustion. The scientific advances of the past century reversed that trend - but the full picture isn’t well understood, Dr McKenzie said.
Scientists know that the capability of Australia’s farmland is being compromised by several long-term chronic soil conditions - chiefly acidity, water erosion and loss of carbon content.
But how profound are these issues? Have improvements in genetics, crop and disease management, and nitrogen fertilisers masked an underlying degradation of Australia’s soil resource base?
“We don’t know,” Dr McKenzie admitted.
“If we don’t build a robust monitoring system, particularly around these chronic issues, we are simply flying blind on the sustainability of our farming systems in the long run.”
He also argues that we may be missing an opportunity to close a potentially substantial gap between the yields we are actually getting, and the yields we could potentially get on a more thorough understanding of land capability.
In some of Australia’s southern cropping systems, the gap could be in the order of 20pc to 30pc, Dr McKenzie said.
“When root disease work began in the early 90s, scientists realised back then that the yield gap was in some cases 50pc.”
“People may think they are doing really well, but if they realise that there is another 10-20pc to be gained, they will work hard on it. If they think they at their full potential, there’s no point doing any more.”
Understanding the extent and potential of our soil resources, analysing what they have to offer under future population and climate change scenarios, and linking them with the global soil resource should be a priority for Australian science, he told the soil conference.
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