Talk:Chernozem

Basic Premise

The Chernozem (literally Black Soil in Russian) soil is significantly blackened by charcoal content. This fact is counter to the understanding established in 1883 by Vasily Dokuchaev that humification alone explains black soil color of Chernozems. That humification alone accounts for the color of the Chernozem is a well established understanding, one that is held by many I have tremendous respect for, including revered soil biologist Elaine Ingham. So I am trying to tread lightly here, laying all this out before improving the article.

Surveys of black C are coming in at 20% of soil organic carbon on average, and >20% in our Chernozem/Mollisol soil types. This information is being picked up in secondary^[1][2] and tertiary^[3] sources. -- Paleorthid (talk) 20:21, 4 February 2016 (UTC)

That is very interesting if true. Seems strange that after all these years they are only now finding that one of the major characteristics of that soil carbon black. I would not be too surprised that this is true, as one way grasslands are maintained naturally is via fires that suppress the brush. The result would be a lot of carbon. You might consider adding something to the as a preliminary finding. Zedshort (talk) 23:38, 4 February 2016 (UTC)

It will give soil scientists a lot to think about. It is telling that Dokuchaev didn't address fire influence. If Dokuchaev had called out fire as a soil forming factor, we would have been on it. Read that Krug 2003 paper, page 28: A chemical examination of a quantity of [corn] stalks gave 18.8 per cent of dry weight of the stalk nitrate of potash That is a lot of KNO₃. In drought-loss corn they reported being able to pour the KNO₃ from the stalk. I find that almost impossible to imagine. Our new world black soils were so fertile in the 1800's that it was a problem for cropping such that bulletins gave advice on how to deal with it. IMO that's kind of an obvious red flag that some some innovative thinking outside the box might be warranted, but our best and brightest soils guy, a transplant from Germany Eugene W. Hilgard, the father of American soil science, was stationed mostly away from the Mollisol belt. He recognized soil as a unique product of place, one that warranted deep and careful examination, but he wasn't in the right place to see the fire pattern. Over time the excessive fertility "problem" corrected itself. The 1800s provided the best opportunity to catch the pattern and we missed the clues. Back to the old-world, excessive fertility probably was not the case by the time Dokuchaev did his work on his Chernozems, it is more on us in North America than it is on the Russian school of soil science. We have followed dutifully in Dokuchaev's don't-look-at-the-black-C footsteps, and IMO we deliberately ignored black C, and for an excellent reason: we didn't need to explore black C to get our job assignments done, as soil geographers, as soil agronomists. IMO we are discovering the role of black C in soils only now because climate change is driving us down new paths of inquiry. The job has changed. -- Paleorthid (talk) 02:55, 5 February 2016 (UTC)

That is quite possibly the most fascinating thing I have heard about soil fertility in a long while. It is a bit frightening as it puts the loss of soil fertility in a stark light. On the other hand it suggests a remedy. Zedshort (talk) 01:19, 8 February 2016 (UTC)

Agree with this Canadian research team when they say a considerable change in conceptual understanding (a paradigm shift) appears imminent^[4] -- Paleorthid (talk) 17:19, 10 February 2016 (UTC)

The aromaticity of resident Black C, a weathering product of char, accounts for its persistence. Mao 2012^[5] found that weathered char residues are composed of ~6 fused aromatic rings in a 2x3 arrangement with 5 carboxyl groups. Mao 2012 reports that Terra preta is almost entirely composed of carbon in this form, that this form occurs abundantly in Mollisols (USA equivalent to Chernozems), that this form contributes most of the cation exchange capacity in Mollisols, and that this form is extractable as humic acid. As you can see in the humic acid article, weathering of fire-derived carbon forms is not one of the three theories of where the humic acid comes from. Our assumptions that humification was the source of the humic fraction is soil prevented us from discovering the role of char. It does appear there is a strong basis for the Ponomarenko (2001) contention that a paradigm shift appears imminent. Soil workers knew the organic carbon was there, we just attributed it to the wrong soil genetic process. Exciting times to be a soil scientist! -- Paleorthid (talk) 18:45, 10 February 2016 (UTC)