Tax wise, I believe that they can't tax you on potential property value. It has to be on what the land is worth now. Otherwise tax boards could say you should build million dollar apartment buildings on your land and we are going to tax you as if they were already erected.
Not all states have Homestead laws; I think NY is one of them. I know that Texas does; that is one reason it is tough to get land mortgages down there. (Ex-MIL owns a plot there.)
As to the taxes, that has been done successfully in a number of jurisdictions close to population centers purely for harassment and a forced sale. City Hall has unlimited (taxpayer) funds; farmers don't.