Talk:Soil formation

Pedolith and Pedoplasmation

These would be useful concepts to be worked into the article:

• Pedolith: upper part of the regolith, above the pedoplasmic front, that has been subjected to soil forming processes resulting in the loss of the fabric of the parent material and the development of new fabrics, including secondary structures such as pisoliths. The podolith may develop from residuum, i.e. from saprolite, saprock or bedrock, or from transported overburden.
• Pedoplasmation (aka pedoplasmic) front: transformation front at which the lithic fabric is destroyed, although commonly with little chemical reworking (pedoplasmation). It forms the boundary between the saprolite (or saprolith) and pedolith in deeply weathered profiles.

source: Butt, C.R.M.; Zeegers, H. (1992). Regolith Exploration Geochemistry in Tropical and Subtropical Terrains. Elsevier N.V., Amsterdam. ISBN 0: 0-444-89095-5. {{cite book}}: Check |isbn= value: invalid character (help). The terms are not familiar to me as a soil scientist (they may be to other soil scientists, though) but the concepts are. The use of the terms fabric and plasma are on the increase in scholarly articles about soil. -- Paleorthid 17:33, 2 November 2006 (UTC)

Other pedogenesis in zoology?

Isn't pedogenesis used for describing the situation where those who haven't yet reached sexual maturity are reproducing? —The preceding unsigned comment was added by Cow2001 (talk • contribs) 11:59, 10 March 2007 (UTC).

Oy! No, I meant "haven't yet reached maturity". Of course they've reached sexual maturity as they can make ofsprings. Am I right? cow_2001 12:01, 10 March 2007 (UTC)

No, they can reproduce without reaching sexual maturity. Exigent nutrients in the soil newly formed from rocks account for why they do not develop into adults; nature finds a way around this problem to ensure that the organisms reproduce anyhow. But this is of marginal importance: someone with real expertise in this area, which would include students of C14 dating, should help out. As an amateur interested in the Neolithic I've run into the subject, but it seems to be very scantly understood (including by me).helio 00:06, 26 October 2011 (UTC)

Citation Needed for State Equation attributed to Dokuchaev

The conventional understanding is that Dokuchaev thought in terms of state factors, but that he did not formulate an equation of state factors. You will see references to Dokuchaev as the originator of "state factors" but that it was others, not just Jenny, but definitely not Dokuchaev, who formulated a state factor equation. If there is evidence to support an alternative understanding, it needs to be cited.

The conventional understanding:

• -"The soil-forming factors (CLORPT), conceived by Dokuchaev and Hilgard (6) and formulated by Jenny (5), constituted the original paradigm that allowed pedology to develop as a science." From: 1991
• -"Dokuchaev’s work prior to and after writing the list of five factors" CLORPT spacial association
• -"Factors of soil formation were proposed...by V.V.Dokuchaev and have been developed in a semiquantitative fashion by Jenny who formulated the now well-accepted Clorpt equation." See page 8 of Tibbet, 2008, Soil Analysis in Forensic Taphonomy. ISBN 978-1420069921
• -"In pedology, the first major elaboration of the state-factor approach initiated by Dokuchaev was due to Chas F. Shaw (1930). Shaw argued that soils are formed by the modification, and partial decomposition and disintegration, of parent material owing to the action of water, air, temperature change, and organic life. He expressed soil formation according to the formula: S = M(C + V)T + D which states that soil, S, is..." From: Geoecology

The support for a different understanding, one closer to the current wording comes from Hans Jenny himself:

• -"How did you arrive at the idea of the state factors? Jenny: I like to think that I arrived at the idea of the state factors independently of other people. But I'm not sure I can make that claim. I know other people, especially Hilgard and Dokuchaev in Russia, thought in terms of state factors, although they did not advance a scheme that enabled people to solve a state factor equation. I did state factor analysis as a graduate student. But I did not know that was what I was doing. The idea did not exist then. But I was thinking of I did draw curves in a speculative way how soil properties would vary with a change in their mean annual precipitation. ... So I put these together in a formal equation, the clorpt formula, and then I noticed to my astonishment that I had discovered "the soil forming factors." And, in fact, later on I found that Dokuchaev in Russia already had set up such an overall equation. But the way he formulated it and defined the individual factors, his equation could not be solved. In my work it was solved because I defined more rigorously and differently the meaning of the state factors." From Hans Jenny on Mount Kiliminjaro, March 1981 in Full text of "Soil scientist, teacher, and scholar : oral history transcript 1979-1983

Jenny clearly states that Dokuchaev did have an equation. Unfortunately, we don't have a verifiable source for that exact formula. I am assuming good faith, but given the tight context with the very incorrect representation of Jenny's formula (I am going to rewrite that consistent with CLORPT), I do not trust that the equation currently posted is one authored by Dokuchaev. I feel we need that citation to keep a Dokuchaev attributed equation that in the article. -- Paleorthid (talk) 05:10, 4 February 2016 (UTC)

Another reference in support of the conventional understanding, demonstrating that a Dokuchaev-authored state equation formula was not generally known:

• - "Dokuchaev (1879a,b, 1883, 1893, 1899b) recognized that the soil is a function of the interplay of climate, organisms, relief, and parent material, all operating over time. Dokuchaev, and later Glinka (1914, 1927), Joffe (1936) and Marbut (1927) considered soil-forming factors as the causes of soil formation and soil properties as their effects. Shaw (1932) prepared the first soil-forming factor equation: S = M(C + V)T + D. ... Jenny (1941) rewrote Shaw’s (1932) soil-forming factor equation: ..." From: Historical development of key concepts in pedology J.G. Bockheim et al. Geoderma 124 (2005) 23-36 -- Paleorthid (talk) 06:22, 4 February 2016 (UTC)

Soil = f(cl, o, p) t_r

Here are 2 solid references with a formula attributable to Dokuchaev. Author Hans-Peter Blume is current.

• -"After Pavel A. Kostychev (1845-1895) had disproved Dokuchaev´s theory of a humus transport by percolating water, he emphasized the great importance of bioturbation beside a deep-founded rooting. Citing Darwin he described the influence of soil fauna [17]. Dokuchaev then changed his mind and accepted bioturbation as a soil forming process [18]. He included soil organisms in his equation of soil formation [19]: soil = f(cl, o, p) t_r in which cl is regional climate, o vegetation and animals, p the “geologic substratum”, and t_r relative age (youthfulness, maturity, and senility)." Blume, Hans-Peter, Charles Darwin and the Discovery of Bioturbation in the Year 1837 'in' Annals of Agrarian Science, vol 9, no. 1, 2011. [19] refers to Dokuchaev V.V. Doklad Zavkavkazskomu Statisticheskomu Komitetu ob Ozenke Zemel’ Voobische i Zakavkazja v Osobennosti. Pochvennye Gorizontal’nye i Vertikal’nye Zony (Report to the Committee of Statistics about Soil Evaluation in General and in Particular. Trans-Caucasia). Tiflis, 1899. In Dokuchaev, V.V.,Sochineija, vol. 6, Moskva, 1951, pp. 379-397. (in Russian).
• -"The idea that climate, vegetation, topography, parent material, and time control soils occurs in the writings of early naturalists. An explicit formulation was performed by Dokuchaev in 1898 in an obscure Russian journal unknown to western writers. He set down: soil = f(cl, o, p) t_r " Jenny, Hans, 1980, The Soil Resource - Origin and Behavior, Ecological Studies (Book 37) Springer-Verlag, New York. ISBN 978-1461261148. -- Paleorthid (talk) 23:55, 4 February 2016 (UTC)

Citation Needed that Jenny's CLORPT was derivative

In the interview in the previous section, Jenny is saying in 1981 he wasn't aware of Dokuchaev's equation until after he developed his equation in 1941. Jenny's formula is not a derivative of Dokuchaev's formula as stated in the article. -- Paleorthid (talk) 05:10, 4 February 2016 (UTC)

Fire

Fire as a soil forming factor is supported by Certini 2014:

Certini, Giacomo (2014). "Fire as a Soil-Forming Factor". Ambio. 43 (2). Springer: 191–195. doi:10.1007/s13280-013-0418-2. PMC 3906481. fire does not lack any crucial requisite to be recognized as a factor of pedogenesis on Earth, the seventh one together with parent material, climate, time, topography, living beings not endowed with the power of reason, and humans.