U.S. soybean prices rose for a sixth consecutive session on Thursday and struck an eight-month high as the dwindling cash supply left from the drought-plagued 2012 harvest sparked commercial buying in futures.
Chicago Board of Trade (CBOT) wheat futures leaped more than two per cent, advancing for the second day in a row, with a falling dollar and technical buying boosting prices, traders said.
Corn also firmed on thin U.S. old-crop supplies and spillover support from soybeans.
All three markets drew support from stronger-than-expected export sales in the U.S. Department of Agriculture's (USDA) weekly export sales report on Thursday.
Soybean futures continued a recent uptrend as a port strike in major exporter Argentina increased the focus on the tight short-term supply of the oilseed.
The strike, and lengthy vessel backups at other South American ports, raised concerns that some global demand could shift to the United States where supplies were forecast to shrink to a nine-year low before the autumn harvest.
"The talk is it was commercial or end-user buying. If they can't buy the cash in the country they'll come to the board and buy futures," said Mike Zuzolo, analyst for Global Commodity Analytics.
"My sources said end-users are locking in soybeans for June shipment. Also, the exports were very good, above estimates, and that is especially true for meal exports," Zuzolo said.
CBOT July soybeans traded in an uncommonly broad 59-1/4 cent range and closed up 5-1/4 cents, or 0.4 per cent, at $14.99-1/2 a bushel (all figures US$). After trading lower at times early in the session, technical buying fuelled a late-session spike to $15.46-3/4, the highest price for a spot-month contract since early November.
Wheat climbed for a second consecutive day and posted its biggest one-day advance in two weeks. The market was due for a recovery after falling to a two-month low early in the week and much of the strength on Thursday was tied to technical short-covering, traders said.
"There is short-covering, they exhausted the selling," said Shawn McCambridge, analyst for Jefferies Bache. "There was support from export sales and the dollar is sharply lower."
CBOT July wheat settled up 14-3/4 cents, or 2.1 per cent, at $7.03-1/4 per bushel.
The USDA weekly export sales report released on Thursday showed net export sales of U.S. wheat last week at nearly a million tonnes, well above analysts' estimates.
The dollar index fell nearly one per cent on Thursday after a slide in stocks sparked by a drop in Chinese factory activity.
Corn prices also recovered after early-week pressure from a record-fast U.S. planting pace last week. But rain has returned and is now slowing remaining field work.
CBOT July corn rose 3-1/2 cents, or 0.5 per cent, to $6.62/bu.
Rainfall over the next week to 10 days in parts of the Midwest will delay remaining corn seedings and possibly cause a shift from corn to soybean acreage, an agricultural meteorologist said on Thursday.
"Acreage reductions are most likely in northeastern Iowa, southeastern Minnesota, central North Dakota and western Wisconsin as rains remain normal to above normal," said Commodity Weather Group (CWG) meteorologist Joel Widenor.
Elsewhere in the Midwest, Widenor said warmer weather next week, with highs in the 80s to lower 90s F, would help dry soils between showers and speed corn and soybean emergence.
-- Sam Nelson and Karl Plume
write for Reuters from Chicago. Additional reporting for Reuters by Gus Trompiz in Paris and Naveen Thukral in Singapore.