The authors wish to acknowledge Mr. Rick Mueller of USDA/NASS for assistance provided in the classification of the spring wheat using the Landsat TM data. USDA/NASS , Spatial Research Section assisted in acquiring the crop statistical data and their support is acknowledged. Mr. Galen Hart and Dr. Craig Daughtry are acknowledged for their critical review of the manuscript. The U.S. Department of Agriculture, Agriculture Research Service and the National Agricultural Statistics Service funded this project