Now I suspect that in the future when agriculture does not use one drop of
petroleum on farming and where about 50% of Earth's population is working
to produce food and where Earth has a controlled total population of about
2 billion people and no more.

I envision farming where farms are no more than 25 hectares. Fertilizing is

all done from the clipped grasses and weeds between rows of crop plants.

And the way to accomplish that is by placing concrete block in rows so that

the push-reel-mower that is human driven or even draft animal driven. That
the concrete block are spaced just so that the pushreelmower can get
through
the rows.

So these block not only become the ideal method of gardening but in the
distant future become the ideal method of Farming.

Archimedes Plutonium,
whole entire Universe is just one big atom where dots
of the electron-dot-cloud are galaxies