Respected commodities investor Dennis Gartman told Reuters he sold "a very large position" in Chicago Board of Trade corn futures on Monday when the reversal occurred. "If I am to be bullish, technicals and fundamentals must be moving in the same direction," said Gartman, publisher of The Gartman Letter. The US Department of Agriculture will release on Friday its eagerly-awaited 'plantings intentions' report -- the first survey-based estimate on how many acres farmers in the United States will plant with corn and soybeans this spring. The department will also issue its estimate of quarterly grain stocks as of March 1, an report that has in the past caused much volatility in CBOT futures. "I wouldn't have any argument with the technical reversal and it matches up with fears of a possible hard landing for China's economy versus a soft landing, so corn is on the cusp right now," said Mike Zuzolo, analyst for Global Commodity Analytics. Active May CBOT corn closed down 16 cents per bushel at $6.47-1/2 on Tuesday, 4.2 percent below the 4-month high of $6.75-3/4 hit early in Monday's trading session. The spot month has rallied about 11 percent since December following a drought in South America. The active May contract reversed course and closed lower on Monday, breaking key support at its 200-day moving average of $6.67-3/4 in the process, a bearish technical close. Key support now lies at its 50-day moving average of $6.43-1/2, then at its 100-day moving average of $6.38-3/4 and after that the $6.31 area is seen as key support. "We've now gone down to the 50-day moving average and a break below that opens up the downside to the March lows of the $6.31 area," Zuzolo said. 'PAY HEED TO REVERSALS' Gartman in his Gartman Newsletter said "despite our enthusiasm for the grain markets they reversed yesterday; that is, corn made a new high for the move and finished the day lower, taking out the previous day's lows on the close. We always pay heed to reversals." Concerns about China's economy combined with prospects for a record large US corn crop this year thanks to stellar crop weather in the heartland were lending weight to the corn market. "There is no hard core evidence any major trendlines were broken but of course that could happen and it could put corn on a downhill course through the end of the quarter, through the end of next week's plantings and stocks reports," Zuzolo said. Technical and fundamental traders said it will be important to see physical demand for corn increase at these levels to avoid further downside moves in corn futures. "My first support is the 50-day at $6.43-3/4 and if that is broken I see trendline support at $6.38," an analyst said. He said the $6.38 trendline support line was formed by the December low, January low and March low. "Should that break down we could go down to the $6.31-3/4 level," he said. Robert Bresnahan of Trilateral Inc. added that if the $6.31-3/4 level is broken it would reverse the upturn in prices, or it could just be a correction if the market stabilizes on Wednesday and Thursday. "You have people who are nervous going into this report (March 30), there have been pretty negative swings from this report before," Bresnahan said.