Agroforestry is a good way to build multi-crop food forests. Nitrogen fixing the soil reducing the need for fertilizers, with mineral rich soils and much better water retention by shading at the correct times of the year.
Building better biospheres should be how we look at future farming if not using automated means, what land we do have should be protected, and used in smarter ways to ensure better more useful yields that are sustainable. Over fertilization of crops causes run-off into our streams and rivers that in the end lead to our oceans causing havoc on the ecosystems there.
Take a look at this video on how simple Agroforestry can be to grow multi-crops.