One of the disadvantage of corn farming is that it is basically a monoculture.
Anyone that has cultivated a small plot knows that you get the best results by practicing crop rotation. That way the soil gets less chance to build up bad organisms that thrive on one type of plant, and the soil gets a chance to replenish nutrients as different crops use different amounts and combinations of the soils naturally occurring minerals.
If on the other hand you grow the same crop year in, year out, you deplete the natural nutrients from the soil, meaning that chemical fertilizers need to be used to replenish what is lost.
Also there is a build up of the bugs that thrive on that particular crop, which leads to the addition of more and more chemical pesticides.
Also, it’s been shown that growing corn organically actually uses 33% less fuel and produces comparable yields.