CBOT soya closed 3-1/2 to 9 cents per bushel lower, with November down 9 at $5.71-1/2 per bushel. January was down 9 at $5.83. "The big issue in here is the idea we're going to get a bigger crop and we'll probably have a cut in usage, exports specifically, and the carryout could get bigger in this next report," said Dale Gustafson, analyst for Citicorp.
The US Agriculture Department will release its November crop report on Thursday.
Traders are expecting this year's output to be near 3 billion bushels, which would be the second-largest US soyabean crop on record. Mostly satisfactory crop weather in South America also was weighing on prices, traders said.
Traders said selling accelerated when the January contract opened below key support at the $5.90 per bushel 50-day moving average. Exports were quiet over the weekend.
Traders said there is almost daily talk that China is seeking or buying US soya. USDA on Monday said 33.1 million bushels of US soya were inspected for export last week, below the inspections of 41.4 million the previous week.
Deliveries on the November contract totalled 495 lots and there were scattered stopping of the soya. Registrations with the CBOT increased to 1,790 lots from 1,484.
Harvest weather has become less of a market factor because the US harvest is virtually complete. Meteorlogix weather service said on Monday it would be mostly dry in the western Midwest this week, with a few light showers expected in the east.
Meteorlogix also said very little rainfall was expected in Brazilian crop areas over the next seven days and mostly dry weather was expected in Argentina.
Some stress on planted soya is beginning to surface in northern Brazil and additional rainfall is needed in Argentina, Meteorlogix said. Cash basis bids for soyabeans in the Midwest were firm and farmer selling remained slow.
On Friday's CFTC Commitments of Traders report for futures and options combined showed that, as of last on Tuesday, large speculators were long 48,508 lots and short 43,238.
The number of long positions increased 4,080 lots from the previous report and the number of short positions increased 1,197. Technical support in the January contract at $5.90 per bushel was broken, driving the contract to a session low of $5.82-1/2.
Resistance was at $5.94-1/2. Soyameal futures closed unchanged to $2.40 per ton lower, with December down $2.10 at $174.10 per ton. Traders said the drop-pressured soyameal in soyabean futures.
On Friday's CFTC Commitments of Traders report for futures and options combined showed that, as of last on Tuesday, large speculators were long 16,464 lots and short 22,630.
The number of long positions increased 328 lots from the previous report and the number of short positions increased 1,040. Soyaoil was down 0.28 to 0.30 cent per lb. lower, with December down 0.27 at 22.67 cents per lb.
Falling soyabean futures weighed on soyaoil, as did weak crude oil prices. Soyaoil has been getting some direction from the volatile crude oil market since soyaoil is a key ingredient in the growing bodiless industry.
Malaysian palm oil futures closed lower overnight. Traders in Kuala Lumpur said the decline reflected a lack of participants as the market reopened after a long holiday break. On Friday's CFTC Commitments of Traders report for futures and options combined showed that, as of last on Tuesday, large speculators were long 27,879 lots and short 12,649.
The number of long positions declined 2,978 lots from the previous report and the number of short positions increased 4,393.