CHICAGO: US old-crop corn futures rose 1.4 percent on Tuesday morning, their third straight day of gains, on worries that supplies will run thin before harvest replenishes storage bins and grain elevators, traders said.
New-crop December corn also rose, but gains were muted on expectations that farmers will plant the largest area with the grain in 75 years as projected by the US government, setting the stage for what could be a record harvest in the fall.
"It is bull spreading in a big way so it has got to be people looking for corn right up front," said Mark Schultz, chief analyst for Northstar Commodities.
Soybean futures also were strong, firming after a weak open due to strength in the corn market. Soy prices, which have risen 5.5 percent in the past three days, remained underpinned by the US Agriculture Department's forecast for a drop in acreage.
US wheat futures also were mixed, with the old-crop May contract edging higher after trading lower for much of the morning due to strength in corn. But forecasts for beneficial crop weather in key growing areas, which should raise already ample supplies, weighed down new-crop months.
At 11:30 a.m. CDT (1630 GMT), CBOT May corn was up 9 cents at $6.64 a bushel while the new-crop December contract was 2-1/4 cents higher at $5.47-1/4 a bushel.
May corn briefly broke through its 200-day moving average on Tuesday and the market continued to hover around that key technical point in midday trading.
The July/December corn spread has widened by 40 percent since the USDA's plantings report was released on Friday morning.
"We have been liking that July/December spread," said Bill Gentry, a broker for Risk Management Commodities. "The spread trade is probably the backbone of it (the corn rally)."
Private forecaster Informa Economics said it raised its outlook for US corn plantings to 96.4 million acres from 95.5 million. Its soybean acreage view was cut to 74.2 million from 75.1 million.
CBOT May soybeans were up 7 cents at $14.28 a bushel.
The new-crop soybean/corn ratio eased slightly to 2.53, still above the 2.5 threshold that the market typically sees a trigger for farmers to plant soybeans instead of corn. But this year's soybean rally has been viewed as unlikely to entice farmers to switch due to warm weather that allowed for an early start to corn planting.
The fast start to planting buoyed expectations of large corn seedings, followed by a bumper crop, this year. USDA said on Monday afternoon that farmers had seeded 3 percent of their intended corn acreage as of April 1, matching the quickest start on record.
CBOT May wheat was 3/4 cent higher at $6.57-3/4 a bushel. New-crop July wheat dropped 1-1/4 cents to $6.68-1/4 in thin trading.
Prices for the benchmark wheat contract failed to fall below Monday's low of $6.49-1/4 after testing that mark early in the session.
Significant rainfall was being received this week in the US Plains this week, which will further boost growth and development of the hard red winter wheat crop, said Don Keeney, meteorologist for MDA CropCast Weather.
"We're certainly seeing showers ramp up in the Southern Plains," Keeney said.
The rain will spread eastward into the southern Midwest and Delta later in the week, helping the developing soft red winter wheat crop.
US winter wheat was rated 58 percent good-to-excellent as of April 1, compared with 37 percent a year ago, according to the USDA's weekly crop progress report issued on Monday afternoon.