Growing more and more food will eventually reach an end point - to create food, you take nutrients away from the soil (you can't create something from nothing). There are only so many nutrients.
Farmers have known this for centuries.
https://en.wikipedia.org/wiki/Summer_fallowAn interesting point you raise there Vod, it is true soil works merely as a medium for growth, nothing more. The nutrients contained in the soil are one of the key elements to ensuring healthy growth and yield.
Precision Agriculture methods have helped, with minimal tillage applications, and nitrogen locking techniques such as cover crops, and rotation, however, this only delays the inevitable.
GM crops have been recently produced that require the uptake of less nutrients, to collect the same yields, however, again GM carries with it controversy, especially as governments do little to help in creating an educational understanding among the general public.
There are current tests underway in London, England that has led to the worlds first underground farm, using synthetic based mediums, and nutrients to produce food, these have successfully yielded watercress, mushrooms and cauliflower and further testing is being carried out on a range of other plants.
There is also research being carried out on 3D printing to a genetic level, that could see protein based foods, developed through growth from cells.
For now we have to look towards sustaining what we have, until we can create what we want.
