A tree is a perfect recycling machine first to using water in the soil draw mineral up into the tree then with CO2 from the air it removes the carbon releasing the oxygen into the air. With the minerals and the carbon is the building materials to make the tree. This keeps going on until the tree either dies or cut down the tree that dies decomposes naturally through rot or fungus breaking it down to the minerals that made it. If cut and burned becomes pot ash which is the white or gray left over in the fire the carbon is combined with oxygen in the burning produces energy through heat and releases CO2. Now that if we take potash it is the minerals needed to build the next tree. Nothing is ever lost.
Going beyond The future might be here right now see AI and computers even micro robots. Every known thing on earth is on the periodic table. The periodic table is a list of known elements. Everything is just like a recipe you would use for bread put a little of this and that with a drop of something else and you have a loaf of bread. Everything that we know is just knowing the recipe and we can build it. In Star Trek they had replicator which could make any food you wanted by just asking for it. We watched 3D printers go from science fiction to on the shelves in Amazon. So what was considered SYFI a few years ago is here. We also know scientific knowledge is far beyond what they tell us. I would not be surprised if the replicators don’t already here. Now where to we get all the elements how about from our waist as recycling a machine that can disassemble everything back to its elements. This would be the perfect recycling part also the oceans have every mineral element that wash off the lands and down to the ocean over billions of years. There is no lack of supply. Elements can not be made or destroyed. IF this is all true farming would be now optional there would be no need for it the lands could return to nature and the garden of Eden could be here again.