Kastanozems occur mainly in the dry parts of the permanent grassland (steppe) regions of the world (the Great Plains of the USA, Mexico, the pampas of Latin America and the Eurasian short-grass-steppe-belt). The estimated total extent of Kastanozems is at about 4.65 million km2.
Kastanozems have a deep, dark coloured surface horizon with a significant accumulation of organic matter, high pH and an accumulation of calcium carbonate within 100 cm of the soil surface. The morphology of dark Kastanozems is not very different from that of the southern, drier Chernozems whereas the light Kastanozems of the south grade into Calcisols.
Climatic gradients in the Kastanozem belt are visible from pedogenic features. In Russia, the darkest surface horizons occur in the north of the Kastanozem belt (bordering on the Chernozems) whereas soils with shallower and lighter coloured horizons are more abundant in the south. The differentiation between horizons is clearer in the north than in the south in line with decreasing length and intensity of soil formation as conditions become more arid.
The typical arable land use is the production of small grains and irrigated cashcrops and vegetables. Kastanozem are also used for extensive grazing. Kastanozems are threatened by different forms of erosion and are often subjects of desertification processes.