Even though it may feel like summer just started, fall harvest is right around the corner in the Corn Belt. Combines are already running in the southeast. That puts the combines not far south of the Corn Belt, where farmers say they'll be rolling within the next 2 weeks, some a lot sooner.

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• Marketing Talk: 2011 corn

Here's a sample pulled from a field north of Des Moines -- first stop on a crop tour that covered 1,200 miles from central Iowa to southern Indiana -- featuring some of the best cropland in the country. This field foreshadowed what was to be seen on down the road: high variability among and within fields.

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• Talk: See more yield guesses

• Grains surge on crop troubles
  
• Rain chances look slim
• Crop slide continues -- USDA
• Bullish corn at $7.40 is risky
• Demand- or supply-driven?
• Patience chokes cash corn prices
• Roy Smith: Basis game