Mud

From Dwarf Fortress Wiki

Indoor mud is created by filling a floor tile with water, then letting the water evaporate. Outdoor mud is created by covering any soil tile with water. Creating mud is essential to providing irrigation for subterranean crops, as well as any crops indoors. The most common sources for mud are the results of irrigation, farming, and draining water sources.

If an underground river or lake has been revealed, muddy tiles that are Subterranean will spontaneously grow tower-cap trees and shrubs. Like trees and shrubs that grow on grass, these can be harvested and will yield wood and subterranean crops.

Building a construction, such as a dirt road, over muddy tiles will remove the mud. Smoothing the floor will also remove the mud.

In adventurer mode mud objects which you can pick up from muddy tiles are edible.^{v0.27.176.38c}