|This article is about an older version of DF.|
Mud is created by covering a floor tile with water and then letting the water evaporate. Creating mud is essential to growing subterranean crops in stone layers - when farming on soil, above ground or underground, no mud is necessary. The most common sources for mud are the results of irrigation and draining water sources.
If an underground river or underground pool 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 dirt road over muddy soil will remove the mud quite quickly. Placing a building on a muddy tile will also clear away mud, even if the tile was smoothed and/or engraved stone - statues work well for this, though animal traps can be placed on any walkable tile, including stairs and ramps. Building a construction or a paved road will also remove mud, but has the disadvantage of destroying engravings and unsmoothing the floor as well as changing any mineral floors to the current layer stone.
In adventurer mode, mud objects which you can pick up from muddy tiles are edible, but only if you are very hungry.