See Village Projects.
Soilworks is a Project in the village that changes what types of soil/grass shows up in your village. It appears all ranks require 7,000,000 in contribution.
Rank 1 unlocks sunny soil. Rank 2 unlocks autumnal soil. Rank 3 unlocks desert sands. Rank 4 unlocks corrupt soil. Ranks 5-8 unknown, will let you know when we get there!
