US soya rose 3 percent to a six-week peak on Tuesday and corn climbed more than 2 percent, moving into positive territory for 2011 as dry weather and outlooks for heat in Argentina threatened each crop. Wheat jumped 3 percent to a six-week high and each market - wheat, corn and soyabeans - easily broke above technical resistance at their 50-day moving averages, touching off buy-stops, a bullish market indicator.
Argentina is the world's second-largest exporter of corn after the United States, the third-largest soya exporter and the biggest exporter of soyaoil and soyameal.
At 10:49 am CST (1649 GMT), CBOT January soyabean futures were up 34-1/4 cents per bushel at $11.97-1/4, March corn was up 12-1/4 cents at $6.31-3/4 and March wheat was up 20-1/4 at $6.42-1/4.
Some support to wheat, corn and soyabean futures also surfaced because of a weak dollar, firm equities markets and gains in crude oil.