Grains got off to a good start like most other commodities on Wednesday after the action by the central banks, led by the Federal Reserve, but by day's end the euphoria had faded as weak fundamentals reasserted their influence. Futures at the Chicago Board of Trade also showed signs last week of breaking their strong negative correlation with the dollar, moving in tandem with the greenback as investors refocused on global growth and demand. Contraction in China's factory sector in November raised caution that demand from the key global consumer of a wide range of commodities could falter, due in part to the debt crisis in Europe, China's major trading partner. "The fundamental commodity picture is not very encouraging, particularly because of an assumed slowdown in demand from China and India," said Philip Gotthelf, president of brokerage Equidex in Closter, New Jersey. "Agricultural products bought by China and India are coming into question. It won't be an outrageous decline in demand as they need to feed their population," he added. Export sales of US soybeans were the lowest in a month in the week that ended Nov. 24 and the 2011-12 marketing year-to-date tally of 782 million bushels was down 35 percent from a year ago. The government expects a 12 percent drop in the year. Although the injection of liquidity by the central banks has brought temporary relief to the euro zone debt crisis that was threatening to engulf Europe and possibly beyond, it will remain in focus for investors. The European Union will hold a summit this week in Brussels to discuss changes to the EU treaty among other issues related to the sovereign debt crisis, which has had an iron grip on markets as investors embraced and discarded risk assets. "From what I read, they haven't fixed anything in Europe," said grains analyst Robert Bresnahan of Trilateral Inc in Chicago. "(French President Nicolas) Sarkozy and (German Chancellor Angela) Merkel are going to do something, but we have not seen any details yet. "I am going to take the cue from the dollar," he said, adding that he was expecting the dollar index to rise close to 80 from its current level of just above 78. Bresnahan said he was expecting grain markets to continue the downtrend until a seasonal upturn in early February. He said market psychology was not friendly toward grain markets at the moment because investors were more prone to "divorcing themselves from risk" rather than taking on risk. In November, CBOT corn futures fell 7 percent, soybeans just over 6 percent and wheat is down more than 5 percent. Grains analyst Shawn McCambridge of Jefferies Bache in Chicago said the optimism in corn had turned negative due to poor exports amid strong competition, while investors who had short positions in wheat were getting out, helping the market to outperform corn and soybeans last week. "The market is going to remain cautious until we see a solution to the crisis in Europe," he added. The US Department of Agriculture will issue its final monthly report of the year in the coming week, updating stocks levels for corn, soybeans and wheat in the United States. But analysts said attention could be focused on global production numbers, especially in South America where corn and soy crops have been going gangbusters in Brazil and Argentina. "I don't think there is going to be enough new information to change anything," grains analyst Don Roose of US Commodities in West Des Moines, Iowa, said about US data. He said that instead, traders could be looking at corn and soybean production in China, among others. Roose said traders will continue scanning for evidence of demand for grains and a solution to the euro zone debt crisis. "The European situation has caused a slowdown in global demand, and China's (factory) data has really spooked people. We cannot afford a (global) meltdown," he added.