 They usually develop in saline parent materials in semiarid and subhumid regions.Properties of the B horizons are associated with sodium ions that cause the clay to disperse readily and swell on wetting, thus closing the large pores and preventing water flow.Solonetzic soils cover almost 73 000 km2 (0.7%) of Canada's land area; most occur in southern Alberta, because of the large areas of saline parent material and semiarid climate.