The U.S. commodity and food prices have increased again in 2011, partly due to some of the same factors that drove 2008 price spikes, but new and very different factors have also emerged, said a research report released on Tuesday by Farm Foundation, a U.S. public charity focusing on agriculture and food system. \"Now, as in 2008, the full story behind rapid increases in agricultural commodity and food prices is not a simple one,\" Farm Foundation President Neilson Conklin said in a statement. The report said that biofuels demands, particularly for corn, is a key factor pushing commodity price increases in recent months because biofuels policy mandates and blending limitations have generated a large, persistent and non-price responsive demand for corn. In addition, weather is more important in 2011 than in 2008. Wheat and barley suffered weather-related production setbacks, but large stocks tempered price increases, noted the report, adding that corn stocks were drawn down when U.S. yields dropped in 2010, and soybean stocks have remained tight. Moreover, a weak U.S. dollar also contributed to a commodity boom in 2011 as the dollar exchange rate remains weak and volatile, said the organization. Farm Foundation, originally created in 1933, works as a catalyst for sound public policy by providing objective information to foster a deeper understanding of issues shaping the future for agriculture, food systems and rural regions.