The name comes from the Russian terms for black (чёрный čjornyj) and soil, earth or land (земля zemlja).[2][3] The soil, rich in organic matter presenting a black color, was first identified by the Russian geologist Vasily Dokuchaev in 1883 in the tallgrass steppe or prairie of Eastern Ukraine and Western Russia.
Chernozem layer thickness may vary widely, from several centimetres up to 1.5 metres (60 inches) in Ukraine,[6] as well as the Red River Valley region in the northern United States and Canada (location of the prehistoric Lake Agassiz).
The terrain can also be found in small quantities elsewhere (for example, in 1% of Poland, Hungary, and Texas). It also exists in Northeast China, near Harbin. The only true chernozem in Australia is located around Nimmitabel, some of the richest soils on the continent.[7]
Previously, there was a black market for the soil in Ukraine. The sale of agricultural land was illegal in Ukraine from 1992 to 2020,[8] but the soil, transported by truck, could be traded legally. According to the Kharkiv-based Green Front NGO, the black market for illegally acquired chernozem in Ukraine was projected to reach approximately US$900 million per year in 2011.[9]
1999: Michael W. I. Schmidt (neolithic biomass burning)[17][18]
As seen in the list above, the 19th and 20th-century discussions on the pedogenesis of Chernozem originally stemmed from climatic conditions from the early Holocene to roughly 5500 BC. However, no single paleo-climate reconstruction could accurately explain geochemical variations found in Chernozems throughout central Europe. Evidence of anthropomorphic origins of stable pyrogenic carbon in Chernozem led to improved formation theories.[16] Vegetation burning could explain Chernozem's high magnetic susceptibility,[19] the highest of the major soil types.[20] Soil magnetism increases when soil minerals goethite and ferrihydrite convert to maghemite on exposure to heat.[21] Temperatures sufficient to elevate maghemite on a landscape scale indicate the influence of fire. Given the rarity of such natural phenomena in the modern day, magnetic susceptibility in Chernozem likely relates to control of fire by early humans.[20]
Humification can darken soils (melanization) absent a pyrogenic carbon component. Given the symphony of pedogenic processes that contribute to the formation of dark earth, Chernozem summarizes different types of black soils with the same appearance but different formation histories.
^Prolonged use may still require replenishment with fertilizers because it easily can get depleted of nutrients.
References
IUSS Working Group WRB: World Reference Base for Soil Resources, fourth edition. International Union of Soil Sciences, Vienna 2022. ISBN979-8-9862451-1-9 ([1]).
^Wallerius J. G. Agriculturae fundamenta chemica, åkerbrukets chemiska grunder. Upsaliae, 1761. 8, 4, 322 p.; The natural and chemical elements of agriculture. London, York: Bell, Etherington, 1770. 198 p.
^'Lomonosov M. V. § 125. // On the strata of the Earth: a translation of "O sloiakh zemnykh" (1763) / translated by S. M. Rowland, S. Korolev. Boulder: Geological Soc. of America, 2012. 41 p. (Special paper; 485) "And so, there is no doubt that black soil is not primordial matter, but that it has been produced by the decomposition of animal and plant bodies over time"
^ abGeikie, A. (1875), Life of Sir Roderick I, Murchison, vol. 1, ASINB0095632AU
^Dokoutchaief B. Tchernozème (terre noire) de la Russie d'Europe. St.-Ptb.: Soc. Imp. libre économ., 1879. 66 p. (Comptes-rendus Soc. Imp. libre économ. T. 4).
^Dokuchaev V. V. Russian Chernozem (1883) // Israel Program for Scientific Translations Ltd. (for USDA-NSF), S. Monson, Jerusalem, 1967. (Translated from Russian into English by N. Kaner)
^Schmidt, M.W.I.; Skjemstad, J.O.; Jäger, C. (2002), "Carbon isotope geochemistry and nanomorphology of soil black carbon: Black chernozemic soils in central Europe originate from ancient biomass burning", Global Biogeochemical Cycles, 16 (4): 70–1–70–8, Bibcode:2002GBioC..16.1123S, doi:10.1029/2002GB001939, S2CID56045817, These data challenge the common paradigm that chernozems are zonal soils with climate, parent material and bioturbation dominating soil formation, and introduce fire as a novel, important factor in the formation of these soils