One of the goals in making this game were to make a lot of the fertilities true to life. Obviously, in the modern era, you can grow pretty much any crop anywhere if you are willing put in the work. And there is virtually every type of mine in every country... BUT the fertilities at work in my game are based on country's real life highest-production resources. So if we take the top 30 mined resources (by tons) for any given country, they are given that fertility in my game. Also, if they are a world leader in the production of that resource, they are given a bonus. Either 200% or 300%.

The fertilities of all the countries were provided by ChatGPT, but honestly it would have been less work to do it myself. Had to double check everything, and it often had me going down roads that I didn't expect. I am not a geologist, or have any true experience with ores and the like. So for example, ChatGPT would tell me that two of a country's top mined resources include Tin and Cassiterite... Well, I now know that Tin is actually smelted from Cassiterite and not mined directly. I was treating them like they were both mined out of the ground. Sheesh.
Hey, so if you are playing the game, and see something stupid like that, please tell me. I am trying to keep some things in the game correct, and this is one of them.

So, all countries share a fertility script, which I can switch around at any time without having to get into code, which makes adding new ones a breeze.

The following is The United States' Fertility.

All that gets put into the country's fertility dictionary through code, and then all countries dictionaries get added to the master fertility dictionary, so all fertilities are in one place.

So, "None" means that it is impossible to gather that resource in that country, and the price in the market is increased due to scarcity.

"Standard" means normal 100% production, with no market change.

"Advanced" means double (200%) production, with reduced market value due to increased supply.

"Expert" means triple (300%) production, with further reduced market value due to the ample supply.

When you are in the game, you can see fertilities in a few places:

Upcoming:

DD4: Building

DD5: Inventory & Items

DD6: Influence

DD7: Market

DD8: ???