The FAO/UNESCO Soil Map of the World (SMW, 1989), constructed at a scale of 1:5 million, aims at providing standardized soil information, and is therefore one of the essential documents in the effort to promote communication between scientists and practical specialists in different countries. The legend of this map forms a bridge between different national pedological schools using various traditions and methods.

The SMW, compiled between 1971–1981, is based on a very broad international consensus. During the last 15–25 years, scientists have made great progress in various branches of soil sciences and practices. For example, an intensive effort to improve soil diagnostics and classification has resulted in a revision of the SMW legend.

The development of pedology in Russia during the last 10–15 years could be characterized by an intensive accumulation of empirical soil mapping knowledge. Pedologists have collected a great amount of new data, including vast amounts of new soil data for the territory of northern Russia, Siberia and the Far East, that has significantly changed the understanding of Russia’s soil diversity and soil geography. For the forested territories, scientists have compiled soil maps at the scale of 1:100,000; for agricultural regions, soil maps were produced at the scales of 1:10,000 and 1:25,000. These maps were used to compile district soil maps at the scale of 1:300,000 and overlaid on the State Soil Map at the scale of 1:1 million. The "Soil Map of the Russian Social Federal Soviet Republics, scale of 1:2.5 million" (SMR, 1988) summarizes current scientific knowledge on the soil environment of the country.

Recent developments at the national and international levels play a role in the process of updating the FAO Soil Map. For the Russian territory, the updates are based on two documents: the SMR and the map’s "program" (the manual for the participants in the development of the soil map). The soil database generated makes it possible to operate using three different soil classification systems: Russian, FAO and Soil Taxonomy (USDA, 1975).

Different soil classifications, as well as the legends for soil maps, are often incompatible because of discrepancies in basic principles, definitions, classification structures, etc. Scientists can only overcome the differences in classification schemes developed by different pedological schools by creating correlation tables, in which classes of one scheme are presented in terms of the other. Naturally, this procedure is based on factor analysis of the correlated soils, comparison of morphological and analytical characteristics, and the like.

Stolbovoi and Sheremet (1995) identify some discrepancies in the process of establishing a correlation between the systems of Russia and the FAO. For example, the Russian grey forest soils do not fully correspond to the FAO major grouping of greyzems, because grey light forest soils in Russian system refer to a soil unit of eutric podzoluvisols. Several soil taxa distinguished in the Russian soil classification, such as sod-podzolic—residually calcareous; sod-podzolic—sod-straw-yellow; podzolic—brown forest; podzolic—deep gley; and sod-podzolic soils with a second humus horizon are treated as one soil unit in the FAO system, namely podzoluvisols eutric..

3.3 SOIL RESOURCES OF RUSSIA

Table 3.1 shows the extent of soils of Russia. The total area covered by soils and other solid surface formations is 1670.34 million ha. The data accuracy is within ±2%.

Podzols constitute the most widespread soil group in Russia, occupying more than 371 million ha or about 22% of the total soil cover area. This type of soil is widespread in northern European Russia and in East Siberia and the Far East. The formation of podzols ties in closely with humid climate and coarse-textured, silicate parent material. These soils are poor in fertility elements; however, they are "warm" in cold climates and allow trees to grow.

The second most important soil group is gleysols, which cover about 275 million ha, or more than 16% of the Russian territory. These soils occur frequently throughout West Siberia and in northern Russia. Gleysol formation is associated with humid climate, flat relief and fine-textured parent materials. In some places these soils are formed from coarse-textured deposits where the groundwater table is close to the surface. Gleysols are normally highly fertile, but in cold climates they are very often affected by permafrost and, due to poor aeration and waterlogging, they are not suitable for woody vegetation.

Podzoluvisols and cambisols occupy about 210 million ha each, or about 13% and 12% of the total area, respectively. Podzoluvisols are widespread in European Russia, where they form from loess-like loams. Because of the leaching processes they have medium fertility, but are nevertheless quite favorable for forest growth.

Cambisols are found throughout East Siberia and the Far East. They are formed from medium-textured residual deposits rich in base cations, which do not allow the podzolization processes to develop. The soils are fertile, well drained and favorable for forest growth.

Leptosols cover more than 144 million ha, or about 9% of the total area. They are widespread in the East Siberian mountains. The soils have very shallow effective depth, which limits tree root development.

Table 3.1 Extent of FAO major soil groups and soil units in Russia.

Greyzems occupy about 45 million ha, or about 2.7% of the area. They occur in European Russia and develop from loess-like loams. The soils have medium fertility, but are suitable for woody vegetation.

Chernozems, phaeozems, kashtanozems and fluvisols cover 180 million ha, or about 10% of the country. They occur mainly in southern Russia, the country’s main agricultural area.

More than 118 million ha (about 7% of the country area) is covered by histosols. They occur in the boggy landscapes of West Siberia.

Other groups, as well as nonsoil formations, occupy about 90 million ha, or slightly more than 5% of the total area.

3.4 GEOREFERENCED DIGITAL SOIL DATABASE

Earlier analyses of the sector, the environment, and the geography had shown that the formats in which the Russian data were stored (papers, tables, texts, etc.) did not fit the requirements of modern information technology. IIASA has therefore developed a number of georeferenced digital databases of the Russian boreal forest sector (and partly of the former Soviet Union) that could be used for different analyses. Some of these databases cover primary geographical and land-use features of the country (soils, reliefs, vegetation, land cover and use, etc.). The IIASA-developed databases are operated by the geographic information system (GIS) ARC/INFO.

The digital georeferenced database for soils of Russia was jointly compiled by IIASA and the FAO (Stolbovoi, 1998, forthcoming). The data come from the following sources: 

• The Soil Map of the Russian Soviet Federative Social Republics at a scale of 1:2.5 million (SMR);
• The State Soil Map of the USSR at a scale of 1:1million;
• The "program" of the Soil Map of the USSR at a scale of 1:2.5 million;
• Topographic Map of the USSR at a scale of 1:2.5 million.

The SMR, published in 1988, provided the main source of soil information. It was compiled by the Dokuchaev Soil Institute with contributions from numerous other soil research centers collaborating as editorial panels. This map represents the latest development and current knowledge of Russian pedology. It synthesizes a great amount of new soil data for Russia (particularly Northern Russia, Siberia and the Far East) and demonstrates a modern concept with respect to soil diversity, geography and resources in a holistic approach.

IIASA used the State Soil Map of the USSR (a complete set of map sheets, including both published and manuscript formats, available exclusively at Dokuchaev Soil Institute) to identify FAO texture classes and phases. The SMR "program" was used to correlate the legends of the FAO Soil Map of World and the SMR (Stolbovoi and Sheremet, 1995). IIASA applied the topographic map to create slope characteristics, texture classes, effective soil depths, and available water capacities for the SMR polygons (see Figure 7.2 , Figure 3.1, Figure 3.2 and Figure 3.3).

The database can operate using the FAO, Russian, and USDA classification systems. Soil polygons can comprise up to eight soil components if the soil extent is more than 4% of the polygon area. The database shows FAO texture classes for the upper 30 cm of the dominant soil in a polygon. Each polygon is characterized by prevailing slope conditions.

The digital soil map according to the FAO classification system is presented in Figure 3.4, according to the Russian classification in Figure 3.5, and according to the Soil Taxonomy (USDA, 1975) in Figure 3.6.

3.5 SOIL CARBON ESTIMATES (TOTAL SOILS OF RUSSIA)

The IIASA study (Rozhkov et al., 1996) has come up with new soil carbon estimates for Russia with respect to the total soils. For this work, we created extensive databases on soil types and corresponding carbon content. We also carried out special assessments on the bulk density of soils, their content of stones, and their content of coarse organic fragments.

The results, using the Russian soil classification system, are presented in Table 3.2. The estimate shows a total pool of 453,367 million tons of carbon in the 0–100 cm layer of Russian soils. Of this total carbon pool, 25% (or 111,279 million tons) is in the form of carbonates, and 75% (or 342,089 million tons) in the form of organic carbon. Of the organic carbon, some 35% (or 119,461 million tons) is accumulated in peat and litter.

For each of the layers 0–20 cm, 0–50 cm, and 0–100 cm, we have constructed digitized maps of the organic carbon content (Figure 3.7, Figure 3.8 and Figure 3.9).

3.6 SOIL CARBON OF RUSSIAN FORESTS

The attributive databases and GIS components that are briefly described above and in the following have allowed us to provide the first assessment of soil organic carbon and carbon of carbonate for different Forest Fund categories, and, specifically, for forested areas. The calculations were done by overlaying several digitized maps of which the major ones were (1) soil carbon map of Russia; (2) map of Land Use; (3) ecoregional map; (4) map of forest enterprises; and (5) map of litter in Russian forests. We performed some calibration of the results for individual ecoregions, based on data from the latest State Forest Account. The accuracy of the results cannot be estimated by traditional methods of mathematical statistics.

Aggregated results for Russian administrative units (as of January 1, 1993) and by economic regions are presented in Table 3.3. Table 3.3 shows the organic carbon in the layers of 0–20, 0–50, and 0–100 cm, carbon of carbonates (for the 1 m topsoil layer), litter and mortmass. Table 3.4 contains the results in a condensed form.

Table 3.3. Carbon of soil organic matter and carbonates for forested areas aggregated over administrative units and economic regions. Total carbon and litter (dry matter) are expressed in Tg, averages are expressed in the table in kg/m².

Table 3.4. Aggregation of Table 3.3. All data in carbon units.

Tables 3.3 and 3.4 present significant information for Russian forest carbon estimations. We limit our consideration to a few comments following from Table 3.3 and some additional calculations.

· Russian forested areas (a total of 763.5 million ha) are estimated to have a content in the top 1 m layer of 129.6 Pg of organic carbon and 30.1 Pg of carbonates, or a total amount of 159.7 Pg (±10%). This means that Russian forests, which cover 44.7% of all Russian lands, contain 37.9% of all soil organic carbon in Russia. Such a result seems reasonable, taking into account: (1) the significant amount of carbon in peat (118 Pg according to the latest estimates; Rojkov et al., 1997), of which the major part is located in treeless wetlands; and (2) the vast areas of shallow mountain and permafrost soils. The surface 0–20 cm layer contains nearly half (45%) of the organic carbon of the top 1 m layer, which illustrates the importance of disturbances (specifically fire) relative to the dynamics of soil organic carbon.

· Carbon in litter (on forested areas) is estimated at 8.72 Pg C, or 11.4 Mg C per ha. The geographic variability of the litter content is very high. It varies from about 10 Mg per ha in the north to about 0 in the steppe zone.

· Detritus (defined as coarse woody debris with a diameter of more than 1 cm) is estimated at 6284 Pg C, an amount comparable to the amount of litter. This estimate supports the importance of detritus carbon in all calculations of forest carbon.

· We estimated data on mortmass (dry matter, defined as all dead organic residuals that have not lost their morphological structure) on forested areas, calculated from Bazilevich’s digitized map. A simple comparison of these data with other components of dead organics in forest ecosystems shows that Bazilevich’s data cannot be used for any calculation of the interactions of actual forests with the global carbon budget.

Table 3.2. Carbon reserves in the soils of the Russian Federation (generalized data)

Note: Numerator = total reserves of organic carbon; denominator = reserves of organic carbon, accumulated in organogenic horizons (peat and litter) with carbon content > 15%.