Can anyone tell me if they have been able to identify soils that look like mollic epipedons but are both hard-setting and massive? How extensive are these soils? How can you draw a line on a soil map to separate them? Do they occur in complex with conventional mollic epipedons? Why are they different (physical, chemical or mineral difference or a soil forming factor/process difference)?by ttcf - Soil Taxonomy Forum
Is CEC Activity Class really needed or useful in any taxa other than Ultisols, Entisols, and Dystrudepts? Even if I missed a few taxa, don't we supply similar or surrogate information at other levels of Taxonomy?by ttcf - Soil Taxonomy Forum
In the definition of a mollic epipedon, the depth to secondary carbonates, a calcic or petrocalcic horizon, duripan is considered for identifying the minimum thickness. Why were gypsic and petrogypsic horizons excluded? Is it because they only occur in the typic aridic moisture regime?by ttcf - Soil Taxonomy Forum
What field observed or measured property can be used as a surrogate for 50% or higher base saturation?by ttcf - Soil Taxonomy Forum
When an A horizon becomes plowed, it becomes a "plow layer." The physcial properties are modified from the pedogenic original, but pedogenesis proceeds immediately after plowing ceases. Why is it a "layer"? Many people argue whether an older "plow layer" that has reformed granular structure after plowing ceases for an extended time is no longer a "plow layer"by ttcf - Soil Taxonomy Forum
Could a Glossary be produced for Soil Taxonomy and the Keys to Soil Taxonomy to help people find definitions such as "rock structure" and "root-limiting layers" more easily?by ttcf - Soil Taxonomy Forum
1- The M ( master horizon ) is used for manufactured liners such as plastic, rubber, geotextile fabric, concrete, or asphalt used to intentionally seal a soil from water and root penetration. An example is the geotextile liners used in landfills, or thick plastic used to line a retention pond. The u ( suffix) is used to indicate the presence of artifacts (defined in Chapter 3 of the 12th Ed. of thby ttcf - Soil Taxonomy Forum
Human-transported material and human-altered material are defined in Chapter 3 of the 12th Ed. of the Keys to Soil Taxonomy, and evidence of their existence provided. If humans leveled the land to produce terraces, creating artificial landforms, it will qualify as human-transported material. If humans altered the soil on purpose beyond standard agricultural practices (such as adding lime), it mayby ttcf - Soil Taxonomy Forum
Suppose a soil in a has three horizons darkened at the surface by OC, named Ap1, Ap2, and Bt1, each of 15 cm thickness, and all three have dark colors moist of 10YR 3/3. If the base saturations by the appropriate method are 60, 55, and 45, what is the epipedon? Now suppose the base saturation is 60, 45, and 40, what is the epipedon?by ttcf - Soil Taxonomy Forum
In a horizon forming from saprolite or weakly cemented bedrock, what is the maximum percentage volume of rock-controlled fabric that can exist before the horizon can be called a B horizon. (I am excluding tranisitonal BC and CB horizons from this question).by ttcf - Soil Taxonomy Forum
Dear Toby: The soil moisture regimes used in the 2nd Ed. of U.S. Soil Taxonomy are defined by measureable criteria in Chapter 3. The SOP could be written to list the steps needed to accomplish the measurements. As far as steps for using Soil Taxonomy, you may find it in the new Illustrated Guide to Soil Taxonomy. Both documents can be found on the USDA-NRCS "soils" web site at httby ttcf - Soil Taxonomy Forum
Ken: I think your simple key would make it much more clear and easier to apply without lab data. "Continous or non-continuous cemented spodic materials = ortstein Continuous cemented non-spodic materials = placic horizon " I do not know what the utility of the thickness would bring, unless someone was trying to dig through it. The continuity is important, but continuity peby ttcf - Soil Taxonomy Forum
I am wondering exactly how to tell a Placic horizon apart from ortstein? Aren't they both cemented by Fe in complex with OM?by ttcf - Soil Taxonomy Forum