CHICAGO (Dow Jones)--Chicago Board of Trade corn futures ended sharply lower Monday, dropping over 4% of their value, as the market retraced last week's gains on outside market pressure and bearish fundamentals.

CBOT May corn ended 16 1/4 cents or 4.46% lower at $3.47 3/4 per bushel. July corn, which is also the most-active contract, ended 16 3/4 cents or 4.48% lower at $3.57 1/4, and December corn ended 16 1/4 cents or 4.12% lower at $3.78.

A rally in the U.S. dollar coupled with an over $2 a barrel drop in crude oil futures sent negative signals through grain markets from the outset, analysts said.

Heavy speculative selling was featured, as the market lacked the fundamental stamina to sustain previous price levels without a supportive spark to attract buying. Speculative funds were estimated sellers of 16,000 lots in corn. Fund activity is a measure of investment money flow in the market.

Favorable central U.S. planting weather had traders and analysts anticipating a strong jump in corn plantings when U.S. Department of Agriculture releases its corn seedings report Monday afternoon.

A lot of acres were seeded during the past weekend that many analysts didn't expect, a CBOT floor analyst said. Farmers are clearly taking advantage of open weather opportunities, as they attempt to avoid any repeats of last year's delayed plantings, he added.

Traders are awaiting Monday afternoon's crop progress report from the USDA. Traders expect planting progress to be in a range of 15% to 23% complete.

Otherwise, unsupportive market influences, with fears of slowing European/world economic growth, provided broad-based pressure on prices.

The T-storm Weather forecast said dry conditions will allow corn planting to continue in most areas of the Midwest through Thursday. On Thursday, changes will occur, as rain and thunderstorms overspread all corn and soybean areas from Thursday night through Friday night. Rain continues at times during the weekend, though it gradually ends from Sunday through Monday. Widespread coverage of 1.00 inch to 2.00 inches will stop planting, but ends topsoil dryness. Four-to-six days of dry weather follows before another round of rain develops, T-storm Weather said.

CBOT oat futures ended lower, with July oats finishing 6 3/4 cents or 3.07% lower at $2.13 1/4 a bushel.

Ethanol futures ended lower. May ethanol ended $0.035 or 2.15% lower at $1.548 a gallon, and July ethanol finished $0.039 or 2.40% lower at $1.583.

-By Andrew Johnson Jr., Dow Jones Newswires, (312) 347-4604