Why not having soil have a standard purity / ferility / humidity based both on biome and geographical place you settled on the map?
It would make sense to find farms in grasslands and in the vicinity of a water source rather than in the middle of a desert / swamp / forest. Also places with intrinsic high purity could become the theatre of interesting fights for land control that are not only motivated on griefing / scamming / whatever.
Also commerce would benefit from spreading the various resources apart from one another. Farmland dwellers would be the main food sellers, but in turn would have to buy most wood / metal.
It would be really interesting to see the development of actual miners towns, fishers town, farmers town and so on...