Agriculture Reference
In-Depth Information
The concepts of diagnostic soil horizons (including epipedons) and diagnostic soil properties are
similar to U.S. Soil Taxonomy. However, according to Soil Taxonomy, all these diagnostic horizons
have virtually the same weight in deÝnitions of soil taxa. In the new classiÝcation of Russian soils,
taxonomic values of different diagnostic horizons are also different. Initially, the system of diag-
nostic horizons was elaborated by V.M. Fridland (1982); however, the authors of the new clas-
siÝcation have revised it considerably and introduced new quantitative and qualitative indices for
soil diagnostics. The list of diagnostic horizons has been enlarged. For the Ýrst time, the group of
anthropogenically transformed horizons has been distinguished; these horizons differ from natural
soil horizons by speciÝc structural status, substantive composition, morphology, and some other
indices.
The deÝnitions of diagnostic soil horizons in the new classiÝcation differ much from the system
of strictly deÝned quantitative characteristics that are used for soil diagnostics in Soil Taxonomy.
Mainly qualitative morphological and analytical characteristics are used in these deÝnitions. In
most cases, quantitative indices are rather diffuse, which is conditioned by the continual nature of
soil bodies that usually have no distinct boundaries in nature. Strictly deÝned quantitative criteria
are used only in exceptional cases. The absence of overly long and complicated keys to soil
diagnostics with numerous quantitatively deÝned parameters (as in Soil Taxonomy) simpliÝes the
procedure of soil correlation during a Ýeldwork.
The new classiÝcation retains most of the soil names that have been traditionally used in Russia,
including the nomenclature decisions of the previous (1977) classiÝcation. The names of taxonomic
categories (soil types, subtypes, genus, species, etc.) are also retained. However, all soil names that
had certain indications of environmental conditions (e.g., forest soils, meadow soils, hydromorphic
soils, etc.) are excluded from the new soil classiÝcation.
GOALS AND CHALLENGES FACING THE DEVELOPMENT OF SOIL CLASSIFICATION
IN RUSSIA
The recently published ÑRussian Soil ClassiÝcation SystemÒ is considered the Ýrst version of
a comprehensive (basic) soil classiÝcation. The most important challenge for the near future is the
improvement of the diagnostics of soil horizons and other criteria; quantitative indices that are used
for soil classiÝcation at low taxonomic levels should also be reÝned. The changes in diagnostic
criteria will result in some changes in the system of soil taxa. The soils that currently are not
included in the classiÝcation because of the complexity of their diagnostics should Ýnd their
adequate place in the next version of this classiÝcation.
The basic classiÝcation of soils is a uniÝed language of scientiÝc communication, the means
to explain the character of soil formation, and the means to encode information on the genetic
diversity and properties of soils. It should serve as the basis for soil mapping, evaluation of land
resources, environmental monitoring of the soil cover, and other applied purposes. In this context,
the problem of revealing not only stable features, but also dynamic characteristics of soils (including
their water [moisture] and temperature regimes, the status of soil biota, and the current conditions
of soil functioning that control the level of
soil fertility and many other practically important soil
features), emerges. The authors of the previous ofÝcial classiÝcation of soils (1977) directly
introduced these important characteristics in their classiÝcation; moreover, the environmental
approach to soil grouping prevailed over the substantive approach in this classiÝcation. From our
point of view, the combination of both substantive (stable soil features) and environmental (infor-
mation on environmental factors) diagnostic indices in the integral system of soil classiÝcation is
not an appropriate decision. Fridland (1982) and Sokolov (1991) suggested that the proÝle-genetic
component of the basic soil classiÝcation should be supplemented by additional and independent
components bearing information on soil regimes (dynamic characteristics
of soils) and soil miner-
alogical and textural features.
However, we should admit that the currently available
data on soil
