GLOBAL grain prices jumped by up to 8 per cent after the release of a key report on US crop-planting forecasts.
The US Department of Agriculture's annual Prospective Plantings report predicted US farmers would plant 38.8 million hectares of corn this year, a rise of 4 per cent on last year and the biggest area planted since 1937.
The USDA also estimated the wheat area sown to rise by 3 per cent to 22.6 million hectares and the soyabean area to fall by 1 per cent to 29.9 million hectares.
Emerald Australia risk and pricing general manager David Johnson said while the USDA increased the area planted to wheat and corn, it also cut its estimates of stocks of both grains.
Mr Johnson said US corn stocks had been reduced by 3.8 million tonnes and wheat stocks were also reduced in estimates.
He said the fall in stocks was evidence of the US feeding more corn and wheat to livestock.
Chicago Board of Trade corn futures prices jumped 6.6 per cent to 644 US cents a bushel ($A246 a tonne) on Friday and wheat futures rose 7.9 per cent to 661 US cents/bushel, or $A235 a tonne, by close of trading on Friday.