The relationships are fascinating to me. Poop is a product that carries substances that are precursors for all plant hormones. Dissolved organic matter and amino acids are two biggies. It is initially hard to reconcile the common advice of not putting meat or other protein sources in a compost pile with the levels of proteins, amino acids, and related enzymes and components that come in manure, which are then broken down even further by the biodome and enter the plant life cycle. While NPK and minor and micronutrients are all important, the hormones and their sources are what make plant magic happen, and are the singlemost fundamental difference between synthetic and organic fertilizers. The papers and studies on the interrelationships of the biochemistry go on and on to the point that a person has to simply choose where to start and where to stop or you end up studying the whole world. Manure is a great place to start.
