CBOT December corn settled up 1-3/4 cents at $3.54 per bushel after dropping to $3.48-1/2, matching its Sept. 21 low.
Corn futures shook off early pressure stemming from the expanding harvest in the US Midwest, where weather is expected to remain mostly dry this week for fieldwork.
Traders continued to adjust positions ahead of the US Department of Agriculture's quarterly stocks report on Friday. The average analyst estimate of US Sept. 1 corn stocks was 2.353 billion bushels, the highest in 29 years, if realized.
Ahead of the USDA's weekly export sales report on Thursday, analyst expected the government to report weekly corn sales at 500,000 to 800,000 tonnes.
The US Energy Information Administration said weekly US output of corn-based ethanol fell to 996,000 barrels per day, while stocks of the biofuel fell to 20.74 million barrels.