* Firm dollar, tepid export demand curb CBOT futures

* Markets consolidate before U.S. holiday weekend

* Concerns linger over dryness in U.S. Midwest

CHICAGO, May 25 (Reuters) - Chicago Board of Trade soybean and grain futures eased on Thursday as a strong U.S. dollar added to concerns about lackluster export demand, traders said.

The dollar rose for a fourth straight session to a two-month high, making U.S. commodities look less attractive to importers.

Favorable weather for planting of U.S. corn and soybeans also hung over agricultural markets, though there are concerns about the risk for dryness to develop, traders said. Supplies of both crops are expected to rise sharply in the coming year due to forecasts for record harvests.

"The crop is off to a great start," Tomm Pfitzenmaier, analyst for Summit Commodity Brokerage in Iowa, said about corn.

CBOT December corn, which represents the crop that is being planted this spring for harvest in the fall, fell 4 cents to $5.16 a bushel.

Nearby July corn futures, the most-active contract , ended 3-1/2 cents higher at $5.90-3/4 a bushel. Strength in the

cash market

helped support the old-crop contract.

Soybean futures finished down 1/2-cent at $13.24 a bushel, off the session low of $13.05. Wheat also weakened, with the most-active contract slipping 2 cents to end at $6.04-1/4 a bushel.

"Cool, dry weather favors planting of any remaining corn and soybean acreage," the U.S. Department of Agriculture said in a daily report. "However, topsoil moisture shortages are becoming more apparent."

The USDA separately reported weekly net export sales reductions of 75,200 tonnes for U.S. old-crop corn in the week ending on May 18. Net new-crop corn sales totaled only 52,100 tonnes, near the low end of analysts' expectations.

Weekly export sales of U.S. old-crop soybeans were 115,000 tonnes, at the low end of trade expectations, and new-crop sales were below expectations at 1,100 tonnes.

For U.S. wheat, the USDA reported net reductions of 45,100 tonnes for old-crop export sales. Net new-crop wheat sales totaled 245,100 tonnes, toward the low end of expectations. (Reporting by Tom Polansek in Chicago. Additioanl reporting by Gus Trompiz in Paris and Naveen Thukral in Singapore; Editing by Sherry Jacob-Phillips, Subhranshu Sahu, Rashmi Aich, Richard Chang and David Gregorio)