Notably, the Westpac-NFF Commodity Index declined by less than 2pc in September.

But many farmers aren't benefitting from this fairly stable price trend, owing to the impact on them of ongoing drought, especially in parts of southern Australia .

Westpac senior agribusiness economist, Andrew Hanlan, says: “The weaker Australian dollar can play a cushioning role during such volatile (economic) times.

"That is exactly what we are seeing at the moment."

On Thursday, the $A was trading lower again, down to US66.8c.

“World economic prospects for the remainder of 2008 and for 2009 are not as promising as they appeared to be just a couple of months ago," Andrew Hanlan says.

"That has triggered a sharp sell-off in global commodity prices – including agricultural – in US dollar terms.

"The Aussie dollar, however, has virtually matched this downward movement – hence the resilience of Aussie dollar commodity prices.

“One positive in this crisis is that in the emerging world – which has become an ever increasingly important market for soft commodities – economic growth is slowing but not slumping. "Also, by its very nature, demand for many soft commodities tends to be less cyclical."

National Farmers’ Federation (NFF) vice-president, Charles Burke, says: “Agricultural commodity prices have risen substantially over the last five years on the back of high demand, spurred on by the global population boom and changing diets, due to more affluent economies, particularly in Asia."

And this has been spurred further by the surge in demand for biofuels.

“When you combine these factors with the international food shortage, reflected in record low world foods stocks, the outlook for Australian agriculture and soft commodities is solid beyond the temporary impact from the current global downturn," he says.

“For Australian farmers, challenges may emerge from the global credit crisis and there is a more impressing need than normal for farmers to actively manage their finances and business during this period."

Over September, the Westpac-NFF Commodity Index fell by just 1.7pc, despite the global turmoil.

It was the depreciating Australian dollar that largely offset the more than 9pc drop in US dollar global agriculture prices.

The index is now 4.7pc below year-ago levels.

Commodities suffering falling prices include canola (-4.9pc), wheat (-4.6pc), cotton (-1.4pc), dairy (-3.3pc) and barley (-3.6pc).

These falls outweighed the rise in the price of wool (1.0pc), sugar (0.4pc) and beef (1.1pc).