I can comprehend the natural system does not need human input. I get that. The Earth was that way for millions of years. With an AP system that produces food, there is a loss of substance during harvest. How is the loss balanced without human input? The way I am imagining it, plant products and even fish are consumed out of the system. In a natural system, the creatures doing the consuming are part of the system. With AP, we are not a direct part of the system. Our waste products do not stay in the system. Please explain this to me, as I am very interested in efficiency and having a system that mirrors the natural way.Originally Posted by urbanfarmer