Farms increased total harvested acreage by expanding cropland or increasing double cropping between 2006 and 2008 especially for the ethanol production ramp-up:
Note: Counties in blue increased the sum total of harvested acreage for major crops either by bringing additional land into crop production or by expanding double cropping. Counties in gray had approximately the same harvested acreage. Harvested acreage declined in counties in red and orange. White areas lack data.National-level data show that both corn and soybean acreage increased over the past decade. In addition to shifting acreage between crops, farms can also increase total harvested acreage by expanding cropland or by increasing double cropping—the practice of harvesting two crops from the same field in the same year. County-level data show where growth in total harvested acres occurred during the rapid runup in ethanol production.
Source: USDA, Economic Research Service calculations based on USDA, National Agricultural statistics Service's Crop Production summaries.