CHICAGO (Dow Jones)--U.S. soybean futures are expected to open weaker Tuesday as global financial and geopolitical worries prompt market participants to reduce risk.

Traders and analysts predict soybeans for January delivery, the most-active contract, will start 3 cents to 5 cents a bushel lower at the Chicago Board of Trade. In overnight electronic trading, the contract dropped 2 1/4 cents, or 0.2%, to $12.19 1/4 a bushel.

Pushing prices lower is strength in the U.S. dollar, sparked by lingering concerns about Ireland's sovereign debt and a military confrontation between North and South Korea. The global issues are weighing on crude oil, which adds pressure to grain and soybean futures, traders said. Crude oil is connected to the agricultural markets because biodiesel is made from soybean oil and ethanol is made from corn.

Soybean futures backpedaled under pressure from the outside markets after initially rising overnight. The market is down about 9% from 26-month highs hit earlier this month on worries about strong demand from China draining supplies.

"Gains overnight in the grain markets were given-up, as the geo-political issues around the world continued to cause uncertainty in the markets," said Mike Zuzolo, president of Global Commodity Analytics & Consulting, an Indiana-based brokerage firm.

However, traders remain nervous about dryness slowing soybean planting in South America. Market participants are hoping Brazil and Argentina--the world's second and third largest soybean exporters, after the U.S.--produce large crops to help ease tightened supplies.

"We appear likely to be well supported on any weakness," said Duane Lowry, analyst for farmassist.com, an agricultural site.

Showers may help improve the condition of crops in the very dry areas of Cordoba and Santiago Del Estero in Argentina during the next five days, according to Telvent DTN, a private weather firm. That will still "not be enough to end concerns," as there is a risk for hot weather next week, the firm said.

Shower activity will favor developing crops in Brazil's northern and northeastern growing areas. However, a trend toward less rainfall in the southern crop areas bears watching, according to Telvent DTN.

-By Tom Polansek, Dow Jones Newswires; 312-341-5780; tom.polansek@dowjones.com