Next Monday, USDA issues its latest crop production report, as well as the monthly World Agriculture Supply and Demand Estimates.  In the meantime, three groups have issued their own estimates. The Linn Group has lowered its corn yield estimate to 149.1 bushels per acre, three bushels less than earlier this month. Linn set corn production at 12.4 billion bushels down from 12.8 billion earlier. For soybeans, the Linn Group cut the yield two bushels, to 41 bushels per acre. The crop is down about 150 million bushels, to 3.05 billion bushels.

Meanwhile, FC Stone now has the corn crop down to 12.3 billion bushels, putting the average yield at 146.3 bushels per acre. That's almost seven bushels per acre less than USDA's current forecast. Stone's corn estimate represents a 1.1 billion bushel drop in production compared to estimates as recent as July. FC Stone also lowered its soybean yield from 42.4, to 41 bushels per acre, putting production at 3.03 billion bushels.

Farm Futures Senior Editor Bryce Knorr says their estimates fall in line with most of the other projections, with corn yields forecast to be about 146 bushels and soybeans at 41 bushels or less.

"We'll be updating our own estimates," Knorr said. "Not only with the weekly crop ratings but also with the weather information for August and see how that may have affected yield potential."

As for next year, Farm Futures magazine expects U.S. farmers will increase production of corn, soybeans and wheat. According to its first farmer survey on planting intentions, Farm Futures forecasts corn acreage at 93.7 million, up nearly 2% from this year. If that happens, that would be an all-time record. Soybean acreage is expected to reach 76.9 million acres, up 2.3%. Total wheat plantings are projected at 58.6 million, up nearly 4%. And Farm Futures says 2012 spring wheat acreage will increase 4.2 %, reaching 14.2 million acres.