> If weeds grow so well why do I have to do so much to my soil or do I ?
It depends if you want to eat "weeds" that typically do OK on poor soil or
heavy feeding cultivated plants that don't. Soil exhaustion is not
something that was disovered recently it has been a controlling factor in
agriculture for many thousands of years and in the case of the Nile and
Tigris-Euphrates valleys (which are less affected than surrounding areas)
significantly altered the course of history.