> Giving a field a year off and cover crops have been done for hundreds of years

Even the old testament talks about letting the land sit fallow for a whole year, so thousands not just hundreds of years.

Years off don't work great when coupled with high land prices and taxes.

Lots of places give property tax breaks for agricultural land, which includes fallow fields.

Correct, the point is getting a $50,000 break doesn't make up that you didn't make $100,000 putting corn on it.