For me, on most of my soils here, this is how I rate my corn: < 120 poor, 120-160 fair, 160-200 good, and 200 on up excellent. I might add that 4 out of the last 5 years has had the majority in the "poor" catagory. REALLY POOR.  Soybeans: < 35 poor, 35-45 fair, 45-55 good, and 55 up excellent. That is here and my own opnion. I dont see why the USDA combines the good/excellent catagory. JMO