CHICAGO, Oct 1 (Reuters) - U.S. corn futures climbed to a seven-month peak on Thursday, boosted by bullish government data indicating domestic stocks were smaller than expected, traders said.

However, soybean futures turned lower and corn pared gains under pressure from an influx of grain sales by farmers who seized on the rally. Wheat futures declined.

"We are holding together reasonably well despite the big pickup in farmer selling. We had a number of soybean plants yesterday reduce their basis, and corn movement yesterday was described as very brisk," said Rich Feltes, vice president for research with R.J. O'Brien.

As of 12:58 p.m CDT (1758 GMT), Chicago Board of Trade December corn was up 3 cents at $3.82 per bushel after reaching $3.85-1/2, its highest level since March 4.

CBOT November soybeans were down 1-1/2 cents at $10.22 a bushel while December wheat was down 7-1/2 cents at $5.70-1/2 a bushel.

Corn futures drew support from larger-than-expected weekly export sales, with the U.S. Department of Agriculture reporting more than 2 million tonnes sold in the week to Sept. 24. Weekly soybean export sales also exceeded expectations at nearly 2.6 million tonnes.

Traders continued digesting Wednesday's quarterly stocks report in which the USDA reported smaller-than-expected Sept. 1 stockpiles of U.S. corn, soy and wheat.

On a bearish note, Argentina, the world's biggest supplier of soy products, plans to temporarily cut soybean and soymeal export taxes to help stimulate export revenue, a local industry source said.

But some analysts questioned whether such a move would succeed in bringing more Argentine soy to the market.

"There has been talk about this for the last month ... it is pretty much in line with previous rumors," Terry Reilly, senior analyst with Futures International, said of the Argentine plans.

Wheat futures fell on profit-taking a day after the CBOT December contract hit an eight-month high on the USDA's smaller-than-expected estimates of U.S. wheat production and stocks.

However, the market had underlying support from concerns about crop weather in key production regions, including dryness in Russia and Argentina.

(Reporting by Julie Ingwersen in Chicago Additional reporting by Nigel Hunt in London and Naveen Thukral in Singapore Editing by David Evans and Matthew Lewis)