CANBERRA, Aug 8 (Reuters) - Chicago wheat, corn and soybean futures rose slightly on Friday, building on the previous session's gains after a decline in prices to multi-month or multi-year lows triggered some demand for U.S. exports.
The most-active wheat contract on the Chicago Board of Trade (CBOT) Wv1 was up 0.1% at $5.18-1/2 a bushel at 0519 GMT, with CBOT corn Cv1 rising 0.1% to $4.07-1/2 a bushel and soybeans Sv1 0.3% higher at $9.97 a bushel.
Wheat was on track for a 0.4% weekly gain and soybeans for a 0.8% weekly gain, but corn was down 0.8% from last Friday's close.
Ample global supply has driven down all three crops. CBOT wheat fell to a five-year low of $5.04 on Wednesday. On the same day, soybeans fell to their lowest level since April and corn dived to contract lows.
Cheap prices have, however, stimulated demand. Weekly U.S. export sales reported by the U.S. Department of Agriculture (USDA) on Thursday showed wheat, corn and soybean volumes above market estimates.
The USDA also reported on Thursday sales of 211,680 tons of corn to Mexico and Guatemala.
Short covering by speculators also helped wheat and corn prices rebound. Commodity funds on Thursday were net buyers of corn for the first time in five trading sessions, of wheat for the first time in eight sessions, traders said.
Nevertheless, a plentiful supply continues to weigh. The Northern Hemisphere wheat harvest is in full swing, with top exporter Russia ramping up deliveries to ports, and large U.S. corn and soy harvests are expected in the coming months.
Farmers in Argentina have sown a larger wheat area this year than last year and early crop conditions are highly favourable, the Buenos Aires Grains Exchange said.
Expana increased its monthly production outlook for the European Union's main wheat crop, but cut its maize forecast.
Prices have tested lows and rebounded, but probably not yet hit bottom, said Rabobank analyst Vitor Pistoia.
"Next week, we will see the truth," he said.