The occurrence, activity and effect of Western species of cicadas on soil formation and their relationship to soil characteristics were studied on 70 semiarid rangeland soils. The distinctive soil structure of some Western soils is attributed to the burrowing of cicada nymphs and has been produced over a long period of time. Filled cicada nymph burrows are called "cicada krotovinas." Little mixing of soil horizons results from the activities of these insects.A new type of blocky soil structure, "cylindrical," is proposed to describe cicada-induced soil structure.Well-drained, moderately permeable, moderately deep and deep silt loam, Brown and Sierozem soils, formed in loess parent materials, are well suited to cicada nymph activity. Few cicada nymphs or krotovinas are observed in soils with coarse textures, fine textural B horizons, and high bulk density.

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Surface soil patterns were classified and studied on 70 semiarid to subhumid areas with relict native vegetation in Utah, Idaho, and Nevada. Three general classes of soil surface conditions were recognized — prominently patterned, weakly patterned, and unpatterned. Prominent and weak patterns were further classified into polygonal surface soil patterns with and without segregation of coarse particles. Surface patterns were found to occur only on bare surface soil between clumps of plants on well‐drained and moderately well‐drained silt loam, silty clay loam, and very fine sandy loam textured soils. Polygonal patterns with segregated coarse particles were observed only on moderately well‐drained planosolic, lithosolic, and solonetzic soils containing basalt pebbles. Surface soil patterns did not occur under vegetation, mulch, stones, or gravel. Cycles of alternate freezing and thawing of the surface soil followed by desiccation result in the formation of polygonal surface soil patterns with and without segregation of coarse particles.