Editing Chernozem (section)

== Theories of Chernozem origin ==
* 1761: [[Johan Gottschalk Wallerius]] (plant decomposition)<ref>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.</ref> 
* 1763: [[Mikhail Lomonosov]] (plant and animal decomposition)<ref>'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"</ref>
* 1799: [[Peter Simon Pallas]] (reeds marsh){{cn|date=July 2023}}
* 1835: [[Charles Lyell]] (loess)<ref name=Geik75>{{citation|title=Life of Sir Roderick I, Murchison|volume=1|first1=A. |last1=Geikie | year=1875 |asin=B0095632AU}}</ref>
* 1840: [[Sir Roderick Murchison]] (weathered from Jurassic marine shales)<ref name=Geik75/>  
* 1850: [[Karl Eichwald]] (peat){{cn|date=July 2023}} 
* 1851: А. Petzgold (swamps)
* 1852: Nikifor Borisyak (peat){{cn|date=July 2023}}
* 1853: Vangengeim von Qualen (silt from northern swamps) 
* 1862: Rudolf Ludwig (bog on place of forests){{cn|date=July 2023}}
* 1866: [[Franz Josef Ruprecht]] (decomposed steppe grasses) <ref>{{citation|title=The Origins of the Russian Chernozem Soil (Black Earth): Franz Joseph Ruprecht's 'Geo-Botanical Researches into the Chernozem' of 1866 |first1=Anastasia A. |last1=Fedotova |journal=Environment and History |volume=16|issue=3 |date=August 2010 |pages=271–293|jstor=20723789 |doi=10.3197/096734010x519762|url=http://www.environmentandsociety.org/node/7607 |url-access=subscription }}</ref>
* 1879: First chernozem papers translated from Russian<ref>''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).</ref> 
* 1883: [[Vasily Dokuchaev]] published his book ''Russian Chernozem'' with a complete study of this soil in European Russia.<ref>''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)</ref>
* 1929: [[Otto Schlüter]] (man-made)<ref name=eckm07>{{citation |first1=Eileen |last1=Eckmeier |first2=Renate |last2=Gerlach |first3=Ernst |last3=Gehrt |first4=Michael W.I. |last4=Schmidt |title=Pedogenesis of Chernozems in Central Europe—A review |journal=Geoderma |volume=139 |issue=3–4 |year=2007 |pages=288–299 |doi=10.1016/j.geoderma.2007.01.009 |url=http://www.geo.unizh.ch/~mschmidt/downloads/Eckmeier_Geoderma_2007.pdf |url-status=dead |archive-url=https://web.archive.org/web/20160308210844/http://www.geo.unizh.ch/~mschmidt/downloads/Eckmeier_Geoderma_2007.pdf |archive-date=8 March 2016  |bibcode=2007Geode.139..288E }}</ref>
* 1999: Michael W. I. Schmidt (neolithic biomass burning)<ref>{{citation|last1=Schmidt |first1=M.W.I. |last2=Skjemstad |first2=J.O. |last3=Jäger |first3=C. |year=2002 |title=Carbon isotope geochemistry and nanomorphology of soil black carbon: Black chernozemic soils in central Europe originate from ancient biomass burning |journal=Global Biogeochemical Cycles |volume=16 |issue=4 |doi=10.1029/2002GB001939 |quote=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 |bibcode=2002GBioC..16.1123S |pages=70–1–70–8|s2cid=56045817 |doi-access=free }}</ref><ref>{{citation|last1=Eckmeier|first1=E.|title=Detecting prehistoric fire-based farming using biogeochemical markers|year=2007|publisher=University of Zurich, Faculty of Science.|doi=10.5167/uzh-3752|quote=It is now an open question as to whether Neolithic settlers did indeed prefer to grow crops where Chernozems occurred or if Neolithic burning formed the chernozemic soils. |url=http://www.zora.uzh.ch/3752|type=Dissertation}}</ref>

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 [[black carbon#Presence in soils|pyrogenic carbon]] in Chernozem led to improved formation theories.<ref name=eckm07/> Vegetation burning could explain Chernozem's high [[magnetic susceptibility]],<ref>{{citation |first1=Eileen |last1=Eckmeier |first2=Renate |last2=Gerlach |first3=Ernst |last3=Gehrt |first4=Michael W.I. |last4=Schmidt |title=Pedogenesis of Chernozems in Central Europe—A review |journal=Geoderma |volume=139 |issue=3–4 |year=2007 |pages=288–299 |doi=10.1016/j.geoderma.2007.01.009 |url=http://www.geo.unizh.ch/~mschmidt/downloads/Eckmeier_Geoderma_2007.pdf |url-status=dead |archive-url=https://web.archive.org/web/20160308210844/http://www.geo.unizh.ch/~mschmidt/downloads/Eckmeier_Geoderma_2007.pdf |archive-date=8 March 2016  |bibcode=2007Geode.139..288E |quote=magnetic susceptibility of soil material may reflect past fires}}</ref> the highest of the major soil types.<ref name="Jordanova">{{cite book|title=Soil Magnetism|editor-first=Neli|editor-last=Jordanova|year=2017|chapter=Chapter 8 - The discriminating power of soil magnetism for the characterization of different soil types
|chapter-url=https://www.sciencedirect.com/science/article/pii/B9780128092392000085
|pages=349–365|doi=10.1016/B978-0-12-809239-2.00008-5|isbn=978-0-12-809239-2|publisher=Academic Press|quote=Chernozem soils exhibit similar features worldwide and are generally characterized by significant magnetic enhancement in the upper soil horizons.}}</ref>  Soil magnetism increases when soil minerals [[goethite]] and [[ferrihydrite]] convert to [[maghemite]] on exposure to heat.<ref>{{Cite journal|url=https://pubs.geoscienceworld.org/claymin/article-abstract/39/1/85/56468/Mineralogy-of-a-burned-soil-compared-with-four?redirectedFrom=fulltext|doi = 10.1180/0009855043910122|title = Mineralogy of a burned soil compared with four anomalously red Quaternary deposits in Denmark|year = 2004|last1 = Nørnberg|first1 = P.|last2 = Schwertmann|first2 = U.|last3 = Stanjek|first3 = H.|last4 = Andersen|first4 = T.|last5 = Gunnlaugsson|first5 = H.P.|journal = Clay Minerals|volume = 39|issue = 1|pages = 85–98|bibcode = 2004ClMin..39...85N|s2cid = 129974901|url-access = subscription}}</ref> 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]].<ref name="Jordanova"/>

[[Humification]] can darken soils ([[melanization]]) absent a pyrogenic carbon component. Given the symphony of [[Pedogenesis|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.