The fall will follow a 31 per cent rise in commodity exports to $196 billion this financial year, according to the Australian Bureau of Agricultural and Resource Economics June issue of Australian Commodities.

ABARE executive director Phillip Glyde said the significantly lower export earnings for next year were mainly a result of lower contract prices for bulk commodities such as coal and iron ore.

"However, export earnings are still expected to remain above 2007-08 levels of $124 billion," he said.

Farm exports are expected to rise by 16 per cent to $31.8 billion this financial year, with a further 2 per cent forecast to $32.5 billion in 2009-10.

"A forecast increase in winter crop production combined with relatively favourable world prices for many agricultural products is expected to support farm export earnings in the short term," Mr Glyde said.

The updated forecast for 2009-10 was marginally higher than ABARE's March estimate, he said.

Farm products whose export earnings will increase include wheat, barley, canola, lupins, peas, rice, raw cotton and sugar.

Mr Glyde said the value of energy exports would fall by about 34 per cent to about $50 billion in 2009-10.

For metals and other minerals, export earnings were tipped to decline by 12 per cent to about $75 billion in 2009-10, he said.