Spot soyabean basis bids were mostly firm in the US Midwest early on Tuesday, reflecting a lack of farmer selling, while corn bids were mostly steady to firm, dealers said.
A tightening in river soyabean bids was lifting soyabean values at processing locations that compete with the river market.
"We're trying to keep up with the Joneses. The river is firm," an Indiana dealer said.
CIF values for soyabeans were up on Tuesday, reflecting continued demand from buyers at the US Gulf. Also, barge freight values eased on Monday, allowing river dealers to pay up for grain. CIF values for corn were steady.
Dealers reported scattered corn movement. Cash sales were slow overall, but some producers were unloading grain because the rewards for deferring sales were eroding.
"The carry in the corn market has dropped significantly, and the same with soyabeans," an Illinois dealer said.
He said carries that in recent weeks were paying farmers 30 to 35 cents per bushel for storing corn and soya until January had dropped to roughly 15 cents.
"Everybody was putting it in the bins. That may be changing," the dealer said.
Rains over the past few days slowed the pace of harvest in the eastern Midwest, limiting the movement of corn and soyabeans. Up to 4 inches of rain fell in southern Ohio, delaying fieldwork for several days. A central Indiana dealer reported about 1 inch of rain.
The US Department of Agriculture said the US corn harvest was 44 percent complete as of Sunday, up from 34 percent last week but down from the five-year average of 53 percent.
USDA pegged the soyabean harvest at 71 percent complete, up from 58 percent the previous week and the five-year average of 70 percent.
At the Chicago Board of Trade, corn futures were called to open 1/2 to 1 cent lower, under pressure from outlooks for a record US corn crop. CBOT soyabeans were called to open 1 to 2 cents lower on harvest progress, traders said.
Cash bids for soft red winter wheat held steady and country sales were very light. CBOT wheat futures were called to open steady to 2 cents lower.