Volcanic Soil and Floodplains?

[Starcleaver]

How do these two work in tandem, if at all? Does volcanic soil remove the floodplain feature? Does the floodplain feature prevent the volcanic soil from being applied? Or do they coexist without issue?

On a map I generated I saw a volcano surrounded by floodplains, and wondered how that would work. With a few eruptions and some luck, if the two stack, I can only imagine how incredible that location would end up being, which gave rise to my wondering of they could coexist, or if one prevented/overwrote the other, etc.

 

[TheMarshmallowBear]

They do not stack, both are Features, Features cannot stack.

As far as I know, given that Soil is created after, nothing. If the Volcano erupts, it will not affect Floodplains in anyway, they will never get "fertilized".