I suspect that capacity to produce food will increase as well; look at how much more efficiently we produce food compared to a century ago.
I believe all the land that will grow food in the southern US is being farmed. With the exception of the forests and there aren’t many of them left.
I know we can grow food more efficiently. But that simply means there are less and less agriculture jobs. A sixteen row plow and a sixteen roll cotton picker can harvest the cotton quicker and more efficiently. But it’s still the same amount of cotton. It can only be grown during the summer months.
Large wheat fields can be harvested in a few days with ten combines going all at once. But it’s the same amount of wheat.