A crop-specific measure equal to the average number of acres planted (or considered planted) to a particular programme crop for the previous five years. The sum of the crop acreage bases for all programme crops on a farm may not exceed the farm acreage. The acreage base was used in determining the number of acres a farmer, under an acreage reduction program, had to remove from normal crop production and devote to conserving uses in order to be eligible for USDA price and income supports. The FAIR Act of 1996 suspends the base acreage provisions of the permanent law.