GRAINS-Corn slips from 18-month high on expectations of increased US plantings

Adds analyst comment, updates prices

CANBERRA, Feb 24 (Reuters) - Chicago corn futures on Monday slipped from Friday's 18-month high as expectations that U.S. farmers will respond to a price rally by planting more corn triggered profit taking.

Wheat futures also fell, with snow cover protecting most U.S., Russian and Ukrainian crops from damage from cold weather. Soybeans edged lower.

The most-active corn contract on the Chicago Board of Trade (CBOT) Cv1 were down 0.5% at $5.02-1/2 a bushel by 0536 GMT after climbing to $5.14 on Friday, the highest since August 2023.

CBOT corn is up around 10% this year thanks to strong export demand for U.S. corn, expectations of lower stockpiles, a weakening U.S. dollar .DXY and adverse crop conditions in Argentina and parts of Brazil.

Speculators have built up a large net long position and although historically they have been slow to unwind such positions, this brings with it the risk of profit taking that pushes prices lower.

However, traders think the U.S. Department of Agriculture will follow the lead of agricultural lender CoBank and project large U.S. corn plantings for the 2025 crop at its annual Agricultural Outlook Forum this week.

Forecasts for rain in Argentina's farm belt and parts of Brazil this week also sucked momentum from corn - and soybeans - by improving growing conditions.

"Argentina's summer crops are declining. Yet the scale of the likely losses is still not enough to make supply unambiguously tight," said independent analyst Tobin Gorey.

"Near-term, Argentina's expected crops would need to shrink a lot more to get prices higher," he said.

In other crops, CBOT wheat Wv1 was down 1% at $5.97-3/4 a bushel and soybeans Sv1 slipped 0.1% to $10.55-3/4 bushel.

Rising corn prices and falling Black Sea supply have helped lift wheat by around 8% this year. Soybeans have risen by a less impressive 5% due to huge anticipated production in Brazil.