US corn and soybeans jumped more than 2% on Monday, according to Reuters, with each futures contract reversing from early losses on a short-covering rally tied to a slow harvest and strong demand for fresh supplies.
The higher prices came despite favourable weather conditions for harvest in the US, where farmers were gathering record-large corn and soy crops. Soymeal futures soared nearly 8% for their largest daily gains in four years.
A slow start to the harvest season had some soybean processors scrambling for beans to cover their short positions while rail brokers pulled offers for the animal feed, traders said.
"Meal is leading the way - crushers are having problems with their hedges," said Dan Anderson, broker at ED&F Man Capital in Chicago.
After the close of trading, the US Agriculture Department said the soybean harvest was 70% complete, within analyst expectations but below the five-year average pace of 76%.
The corn harvest was only 46% done, below the average pace of 65 percent, USDA said.
"We still have a lot of corn to harvest. We have some harvest pressure moving down the pipe; we're just not seeing it today," Anderson added.
Chicago Board of Trade corn futures for December delivery settled 10 cents higher at $3.63 per bushel, just below their two-month high of $3.65 reached on Friday.
CBOT November soybeans gained 28-1/2 cents to $10.06; while December soymeal was up $26.60 to $376.80, the highest level since Sept. 12.
CBOT December wheat climbed 5 cents to $5.22-3/4, rebounding from an earlier one-week low.
Regulatory data released on Friday showed speculative investors, including hedge funds, extended their long, or bullish, bet on corn futures and decreased their short, or bearish, bets on soybeans and wheat.
"Fundamentally we have a lot of grains and oilseeds around the world. We are just about halfway through the US harvest and we really do know what yields look like for corn and soybeans," said Graydon Chong, Rabobank senior grains analyst.
Last week, US soybeans rose to their highest since mid-September, corn hit its highest since Aug 22 and wheat touched its highest since early September.
Rain delays in the US harvest, dryness in Brazilian soybean-growing belts and bargain-buying have helped corn and soybeans recover some ground since they hit five- and 4-1/2-year lows respectively at the start of the month.
Worries about Brazilian soybean crops were eased by scattered rains that fell in the country's centre-west and southeast agricultural areas on Friday and by forecasts for heavier storms this week.