Pedologists generally agree that mature soils are a product of soil forming processes driven by energy inputs provided by soil forming factors (parent material, biota, climate, and topography) over a pedogenic time span of centuries to millennia. Many of the major taxa in Soil Taxonomy were created to group various mature soils which can also be considered “steady state” or “static” entities because they have attained a quasi-equilibrium with their unique environments. In fact, reciprocal relationships between climatic, vegetative, and soil entities produce and define the major regional and global ecosystems recognized on earth and contribute to concurrence between distributions of soil orders and global ecosystems. Some soil properties can, however, be impacted by land management and use wherein changes in soil properties are incurred on a human time scale of decades or centuries. Such properties are referred to as dynamic properties in contrast to static properties generated in pedogenic timeframes. Dynamic changes in soil properties: i) disrupt pedogenic steady states, ii) impact soil quality, and iii) affect the capacity of soils to function. Management practices that often significantly alter dynamic soil properties are those induced by tillage, drainage, irrigation, intensive grazing, and the addition of soil amendments leading to erosion, oxidation, compaction, mixing of horizons, and changes in nutrient, base status, and pH levels. From a taxonomic perspective, undesirable consequences occur when dynamic soil properties are used as diagnostic criteria. Often the classification of pedons affected by management will differ from that of steady state pedons at categorical levels as high as the order even though basic ecosystem parameters are invariant. Although one of the basic tenets of Soil Taxonomy (2nd Ed. p 16) is that “differentiae keep an undisturbed soil and its cultivated or otherwise human-modified equivalents in the same taxon insofar as possible”, many current differentiae will not meet that expectation. Possible solutions are: i) select differentiae that are not dynamic properties or ii) require that only pedons representing the pedogenic steady state condition be selected for classification of polypedons into series. Such a protocol has previously been suggested by Smith (The Guy Smith Interviews: Rationale for Concepts in Soil Taxonomy p.18) in regard to eroded Mollisols. Because current diagnostic criteria effectively group pedogenic steady state soils, the most logical approach may be to focus attention on a procedure to group both pedogenic steady state pedons and associated human-modified pedons into the same series even though the altered pedons may classify into different taxa at categorical levels above the series. It is suggested that a category similar to the current phase be created, but without the requirement that these newly defined phases classify the same as the series. The official series description would provide a description and classification of the pedogenic steady state, identify phases created for pedons altered by management practices, provide a range in characteristics for the various phases, and provide taxonomic classification of each phase at the family level. Whereas series classifications would be appropriate for regional or global soil maps, phases would be appropriate for large scale soil survey maps and interpretative applications. Users of soil survey information using the proposed protocol would be able to relate the distribution of series classifications to the distribution of regional and global ecosystems; whereas, users interested in human impact on our soil resource could compare the classification and properties of series to those of the various phases of series. Such a revision of Soil Taxonomy will facilitate assessments of inherent differences in soil quality between natural steady state soil entities as well as evaluations of dynamic changes in soil quality due to human impact. In our opinion, Soil Taxonomy must address and differentiate both i) pedogenic steady state soil properties and inherent soil quality from ii) dynamic properties and the influence of land management on soil quality.