Soybean futures prices plunged Monday to their lowest close in nearly four months on the Chicago Board of Trade as the accelerating harvest brought new supplies to the market.
Grain futures also finished lower, with oats for December and March delivery closing down the allowable limit of 10 cents a bushel.
On other markets, sugar and cocoa futures were sharply lower, livestock and meat futures were sharply higher, energy futures rose, precious metals were mixed and stock index futures weakened.
Soybeans for delivery in November plummeted more than 26 cents to settle at $8.0625 a bushel, the lowest settlement price for soybean futures since June 1, when the July contract finished at $8.0175.
On Aug. 24, soybeans for September delivery fell to $8 a bushel in intra-day trading but settled that day at $8.315.
Fine harvesting weather in the Midwest and rains in major soybean-growing areas of Brazil and Argentina prompted heavy selling, analysts said.
Corn Harvest Pressures
"The market's very much on the defensive with the harvest going on," said Victor Lespinasse, a trader with Dean Witter Reynolds Inc.
In addition to the harvest pressure, a dearth of significant export orders has limited buying interest in soybean futures, said Cathy Leow, an analyst with Thomson McKinnon Securities Inc.
"Demand is eventually going to drive us higher, of course, but . . . the longer we wait before we see some demand, the lower we're going to go," she said.
Harvest pressure also weighed on the corn market, while wheat prices fell on a lack of significant new export business, analysts said.
Wheat settled 3.5 cents to 5.25 cents lower, with the contract for delivery in December at $4.2225 a bushel; corn was 3.25 cents to 5.5 cents lower, with December at $2.8075 a bushel; oats were 5 cents to 10 cents lower, with December at $2.445 a bushel; soybeans were 12.5 cents to 28.75 cents lower, with November at $8.0625 a bushel.
Sugar futures prices fell dramatically on New York's Coffee, Sugar & Cocoa Exchange in a selloff triggered by the sharp drop in soybean futures, analysts said.
Prices for March through October, 1989, delivery skidded the 0.5-cent-a-pound daily limit, while most contracts for nearer-term delivery, which are not subject to the limit, fell even further.
Sugar for October delivery settled 0.5 cent lower at $9.49 a pound.
Cocoa futures declined steeply in a continuing reaction to the International Cocoa Organization's failure earlier this month to devise a means of supporting prices.
Prices are at 13-year lows, and cocoa "looks like a terminally ill market with no cure in sight," said John Gambino, a technical analyst with Merrill Lynch Capital Markets.
Cocoa for December delivery fell $45 to $1,124 a metric ton.
Unexpectedly strong packer demand for hogs and fattened cattle helped push some livestock futures up the 1.50-cents-a-pound daily limit on the Chicago Mercantile Exchange, analysts said.