U.S. soybean futures climbed to an eight-month high on Tuesday boosted by a weaker dollar, harvest delays in Argentina and the strength of the currency of another key exporter Brazil.

Wheat and corn futures on the Chicago Board of Trade also edged up as the dollar fell to its lowest level in nearly eight months against a basket of currencies on Tuesday.

May soybeans on the Chicago Board of Trade were up 0.8 percent at $9.35-3/4 a bushel at 1157 GMT, after earlier rising to a peak of $9.36-1/4, the highest for the most active contract since mid-August.

Commonwealth Bank of Australia analyst Tobin Gorey said the market was supported partly by the slowing pace of the harvest in Argentina and the strength of Brazil's currency.

"Fieldwork progress has been hampered by periodic rain interruptions, with forecasters expecting further delays in the next 10 days or so," he said in a market note.

"And improving planting prospects for U.S. corn have largely soothed the markets' worries over higher soybean acres."

Brazil's real currency strengthened after a parliamentary committee on Monday recommended impeachment proceedings against President Dilma Rousseff. The rise in its value makes exports less attractive in local currency terms.

U.S. wheat futures were slightly higher, boosted by a slight deterioration in crop conditions.

The U.S. Department of Agriculture, in a weekly report, said 56 percent of the U.S. winter wheat crop was rated good to excellent, down 3 percent from last week.

Analysts surveyed by Reuters had expected the U.S. winter wheat condition ratings to remain unchanged at 59 percent good to excellent.

CBOT May wheat was up 0.6 percent at $4.50 a bushel while May wheat in Paris stood 0.2 percent higher at 152.00 euros a tonne.

Dealers said a stronger euro helped to cap gains in Europe.

"The sudden strength of the euro is a great disappointment, a new burden for EU export prospects," one European trader said.

Corn prices were higher with CBOT May up 0.7 percent at $3.59-1/4 a bushel.

Dealers said adverse weather in Brazil provided some support for the corn market.

Forecasts for a record winter corn crop in Brazil look overly optimistic after summer rains ended sooner than expected with the weakening of El Nino weather patterns, which could prolong the country's recently aggressive imports of the grain.