An ideal circular economy is one that, beyond circulating as much as possible materials in the community before giving them back to nature, gives them back paying attention to replenish natural stocks where they have been undermined. Therefore creating a condition of equilibrium between natural materials input and output where the repetition of starting conditions secures – theoretically to infinity – the reproducibility of the economic process. The essential renewability condition about biomass cycles is the conservation of balance in nutrients stocks and in the composition of topsoil, especially for the organic component. The soil, indeed, provides nitrogen, phosphorus, potassium and other chemicals to the plants, that get the other elements they need from water and ...