What do you call synthetic. you really think they can make millions and millions of tons of synthetic. Actually you can call it all organic. Just because it ain't ground up plant material or out of a cow's tail doesn't make it not organic. Because if you look it up you'll see most fertilizers are dug out of the ground there's massive deposits of it. Yes some is created by mixing natural products but doesn't that still make it organic????
https://www.yara.com/crop-nutrition/why-fertilizer/production-of-fertillizer/
I call synthetic fertilizers anything made from natural gas, oil and chemically derived acids. And they do make millions of tons of synthetic fertilizers. The NPK in these fertilizers may or may not have come from the ground in some fashion.
Nitrogen is the main component and the only component that cannot be mined in fertilizers. The P and the K in fertilizers can be mined but are radically changed by chemical processes.
Way back in 1909 there was a man named Fritz Haber. He figured out how to convert atmospheric nitrogen into ammonia. At the time he didn't really understand what he had discovered but soon found out that he could make explosives and thus the mountains of ammonium nitrate that were left over after WW1. Someone found out that these leftover explosives made great fertilizers, so he and a guy named Bosch got together and the result is called the Haber-Bosch Process of converting atmospheric nitrogen into nitrogen plants can use, todays synthetic fertilizer.
There are 3 ways of providing nitrogen to plants. Atmospheric nitrogen through lightning and rain. Biological nitrogen through consumption, excretion and decomposition. Industrial nitrogen fixation as I explained about Mr Haber. The biological means of providing nitrogen is called organic in today's vernacular.
This biological method is self-explaining. Something is eaten and excreted. Thus the manure. Something grows, dies, decomposes and reverts back to its beginning, NPK. The same P and K used in synthetic fertilizers is sometimes used in organic fertilizers only it is not adulterated by the use of acids. It is used as is in organic fertilizers.
Miracle Grow is finally seeing the light. They are producing a couple of authentic organic fertilizers and a compost. Unfortunately, they are still manufacturing synthetic fertilizers as well.