Define "enough"? The article in question is about Arkansas and broad acre farming, there is 600+ million acres of farm in the midwest down to the delta 99% of which isn't close to a major population center. There is lots of pressure in areas of California and all up and down the west coast up to Vancouver.. but that is a trivial amount a farm land in the grand scheme of things (and specialized due to climate, water, and market access issues that don't apply to most farm land in the US or really anywhere)