Corn and wheat also rose, supported by weather risks to South American and US crops, respectively, while an easing dollar further bolstered Chicago grain futures.
The most active soybean futures contract on the Chicago Board Of Trade was up 1.8 percent at $10.00-3/4 a bushel as of 1150 GMT. It earlier reached its highest since Jan. 30 at $10.02-3/4.
Soymeal futures set several life-of-contract highs, including a peak of $355.6 per ton for March.
After rain late last week calmed investor worries about crop damage in Argentina, forecasts calling for a drier week ahead and potentially scorching temperatures stirred up the market again on Monday.
"We're in a weather market with its ups and downs," Sebastien Poncelet of consultancy Agritel said. "We're seeing both a lack of moisture in Argentina, with the weekend showers far from sufficient, and too much rain in Brazil."
Further yield losses are likely for Argentine corn and soybean crops due to the persistent dryness while in Brazil wet weather will delay soybean harvesting and planting of the second corn crop, Thomson Reuters Agriculture Research analysts said in a note.
Traders will be monitoring weather conditions in Argentina, given projections for rainfall in Argentina next week and divergences on temperature forecasts for the coming days, Poncelet added.
The most active CBOT corn futures gained 1.0 percent to $3.65-1/2 a bushel, recovering its losses from the last session. CBOT wheat climbed 1.7 percent to $4.56-3/4 a bushel, also recouping a similar-sized loss from the previous session.
Drought affecting parts of the US Plains hard red winter (HRW) wheat belt was continued to lend background support to wheat.
"There is concern about HRW wheat in the US that is underpinning prices, although the crop situation is far from irreversible," Poncelet said.
Grain markets have also been supported by bouts of short-covering by investment funds holding large short positions.