Reversibility in agro-industrial systems: CHNOPS as a model
Reversibility of industrial and agro-industrial processes: principles, diagnostics and applications

The natural cycles of carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur constitute systems in which matter circulates without irreversible degradation. These cycles combine physicochemical and biological processes that ensure the continuous transformation of matter, while maintaining it in forms compatible with reentry into the cycle.

The elemental flows within these cycles are transformed, separated, recombined, and then reintegrated, without the accumulation of persistent compounds or the formation of inseparable mixtures.