This sounds like a dumb question, but it is very apropos. It happens on farms all across the northeast and Midwest. Real farmers grow corn and alfalfa, so they do. Multiple years of corn makes drainage worse as the soil structure collapses and machinery compaction squeezes out what little porosity the soil originally had. In Canada, on silt soils, they now tile on 25 ft space as 50 ft no longer works because of compaction and over worked soils. As I mentioned in the November issue, 15 years of alfalfa grass sod did not remove the yield and root limiting pan that restricted roots to only 7 inches of soil. It was like a paved road underneath. Nearly every, somewhat poorly drained or silty/clay, field I have dug in has a yield/ root/drainage limiting compaction when it was plowed while too wet sometime in the past .