GRAINS-Wheat futures lower on improving U.S. Plains weather

* Wheat falls as U.S. crop ratings improve, rains in forecast

* USDA plantings, quarterly stocks data due on Thursday

* Fears of U.S.-China trade war subside

(New throughout; updates prices, adds quotes; changes byline, dateline, previous HAMBURG) CHICAGO, March 27 (Reuters) - U.S. wheat futures declined on Tuesday as rains in the southern Plains breadbasket boosted prospects for the region's drought-hit winter wheat crop, analysts said. Corn and soybean futures drifted lower, with traders reluctant to stake out new positions ahead of key data due this week from the U.S. Department of Agriculture (USDA). The government was scheduled to release its U.S. planting intentions and quarterly grain stocks reports on Thursday. As of 12:40 p.m. CDT (1740 GMT), Chicago Board of Trade May wheat was down 5 cents at $4.49-1/4 per bushel. May corn was down 1-1/2 cents at $3.72-1/2 a bushel and May soybeans were down 4-3/4 cents at $10.20-3/4 a bushel. Wheat futures fell the most on a percentage basis on improving weather in the southern Plains, where winter wheat has resumed growth after its winter dormancy, a time when the crop tends to require increased moisture. The USDA on Monday rated 13 percent of winter wheat in Kansas, the top producer, in good-to-excellent condition, up from 11 percent last week. However, ratings are down significantly from a year ago, when 38 percent of the state's wheat was rated good to excellent. Showers this week could help to recharge soil moisture. "The rains are too late for some wheat fields, but other wheat still has the opportunity to recover a significant amount of previously lost yield," INTL FCStone chief commodities analyst Arlan Suderman wrote in a note to clients. CBOT corn and soybeans declined as traders adjusted positions ahead of Thursday's USDA reports. Funds hold a net long position in both commodities, leaving those markets vulnerable to long liquidation. Analysts expect the government to project U.S. soybean plantings for 2018 at a record-high 91.1 million acres and corn plantings at 89.4 million acres, down from 90.2 million in 2017.

Analysts also expect the USDA to report record-high March 1 corn and soybean stocks, reflecting several years of bumper harvests. Soy and corn futures drew early support from reports that the United States and China, the world's top soybean buyer, were negotiating to avert a trade war. The news also helped lift Wall Street.

CBOT prices as of 12:39 p.m. CDT (1739 GMT):

Last Net Pct Volume

change change

CBOT wheat WK8 449.25 -5.00 -1.1 44007 CBOT corn CK8 372.50 -1.50 -0.4 91251 CBOT soybeans SK8 1020.50 -5.00 -0.5 64735 CBOT soymeal SMK8 373.30 -1.70 -0.5 30989 CBOT soyoil BOK8 31.52 0.06 0.2 26306

NOTE: CBOT May wheat, corn and soybeans shown in cents per bushel, soymeal in dollars per short ton and soyoil in cents per lb.

(Additional reporting by Michael Hogan in Hamburg and Colin Packham in Sydney; editing by Jane Merriman and James Dalgleish)