The new Soil Survey Manual (2014) discusses saprolite on page 55. It would be good however to have a comprehensive glossary of this and many other terms. I have been working on a draft of one. For saprolite this draft says: "Saprolite - Noncemented, relatively soft and friable soil material that retains the particle arrangement and fabric of the original bedrock from which it was derived. Dueby cditzler - Soil Taxonomy Forum
Hi Andrew. Good questions. Because the ochric is a "catch all" epipedon (for all surface layers that don't meet the criteria for any other epipedon), the rules have always been somewhat confusing. I'll try to answer your questions as best I can given the vagaries of the ochric definition. And as you point out, in the end there is little practical significance to most of thiby cditzler - Soil Taxonomy Forum
There is no such requirement for the carbon in the mollic (or umbric) epipedon. It could be included as a criterion, but then we would have to consider how to actually determine this. Doing that would likely be problematic because a surface horizon may have very old carbon (as in human transported material), but it will also have newer carbon from recent vegetation. There may be a way to make a meby cditzler - Soil Taxonomy Forum
By definition the albic horizon must be composed of 85% or more albic materials. So if the E part in your example makes up at least 85% of the horizon, it qualifies as an albic horizon. If the E part is between 15 and 85%, and the B part is argillic, kandic or natric, then this is by definition a Glossic horizon. If the B part is spodic or cambic, then it might be considered as a part of the spodby cditzler - Soil Taxonomy Forum
Gregg you are asking good questions and if you and your colleagues pursue this to the point of improving Soil Taxonomy that will be a good thing. One point of clarification I should stress about my previous comments is that the currently accepted subaqueous soils in Soil Taxonomy DO have GENETIC horizons (A, sometimes B, and C). For the most part they DON'T have the more rigorously defineby cditzler - Soil Taxonomy Forum
When we incorporated the concept of subaqueous soils into Soil Taxonomy, the very short daily period of exposure to the atmosphere was, as you would expect, designed for the upper elevation limit in tidal settings along the coast. We were aware that some potential inland soils that could be considered subaqueous soils, have very long cycles (decades to centuries) where the surface water recedes anby cditzler - Soil Taxonomy Forum
Another important change was that ICOMOD introduced "Spodic Materials" as a diagnostic property. See pg 22/23 of the latest Keys. To be a spodic horizon, the layer must have spodic materials. Item 1 of the required characteristics for spodic materials includes both pH and carbon. Item 2b3 addresses iron and aluminum. The spodic horizon, by definition, must contain spodic materials, so thby cditzler - Soil Taxonomy Forum
A glossary of soil taxonomy terms could be developed. Maybe it should be. For now, many terms (including your examples) are in the KST index so information describing them is not too hard to find.by cditzler - Soil Taxonomy Forum
This illustrates how confusion exists about these terms. I don't really have a good answer to your question other than to say I think the term "plow layer" is a sort of informal term that really is not intended to impart a judgement about pedogenesis. There really seems no doubt (at least to me) that the main properties of an Ap horizon (especially those that are darkened by om) areby cditzler - Soil Taxonomy Forum
The terms layer and horizon are sometimes used interchangeably, even by pedologists, but this is not technically correct. The difference in the terms meanings is rather simple and is discussed briefly in the Soil Survey Manual (p. 60). It probably should be explained more clearly in Keys to Soil Taxonomy. A soil horizon has properties resulting from pedogenic processes. A soil layer has propertiesby cditzler - Soil Taxonomy Forum
In each of the cases you cite, the soil has an umbric epipedon. Note that the base saturation criteria for the mollic epipedon (item 4 in the key) specifies that it is 50 percent or more "throughout". The criteria for the Umbric states that it is less than 50 percent "in some or all parts". For your examples, the epipedon has base saturation less than 50 percent in some part. Eby cditzler - Soil Taxonomy Forum
Clearer differentiation between ortstein and the placic horizon in Soil Taxonomy is needed. The main issue seems to be that within Spodosols, the criterion appears to simply be thickness, with the placic being < 25mm, and ortstein being 25mm or more thick. This would seem to imply that ortstein and placic horizons are essentially the same thing. However, it is clear from reading the discussionby cditzler - Soil Taxonomy Forum