4K. Mudcracks also known as desiccation cracks or mud cracks are sedimentary structures formed as muddy sediment dries and contracts. Crack formation also occurs in clay-bearing soils as a result of a reduction in water content. Naturally forming mudcracks start as wet, muddy sediment dries up and contracts. When this strain becomes large enough, channel cracks form in the dried-up surface to relieve the strain. Individual cracks spread and join up, forming a polygonal, interconnected network. The shrink–swell capacity of clay refers to the extent certain clay minerals will expand when wet and retract when dry. When the water dries up these clays contract, shrink. Cracked exhausted split soil land barren droughty thirsty desert waterless global warming salt salinization.