Soil Map of Poland According to FAO Legend with Different Number of Soil Mapping Units

European Soil Bureau  Research Report No. 4

Creating an FAO-compatible soil map of Poland

European Soil Bureau  Research Report No. 4

Summary

Four versions of the soil map of Poland according with the FAO legend were elaborated during the period 1971-1994. These maps differ in scales and the number of soil mapping units (SMU). The number of SMUs depends on the number of soil typological units (STU), the level of generalisation during presentation of texture and on parent material of soils, as well as on the method of map editing. In general, the smaller the number of SMUs, the poorer the representation of the soil cover characteristics. In order to determine such relations, the four versions of the soil map of Poland were analysed for three test areas with significantly different landscape characteristics.

S. Bialousz

Warsaw University of Technology

Plac Politechniki, 1

PL-00661Warsaw, Poland

The analysis was completed with the following conclusions

1.for areas where landscape units are clearly diversified (mountains), the decrease in the number of SMUs has the smallest influence on the quality of soil cover representation;

2.for flat areas with a high degree of heterogeneity of texture and soil moisture, the decrease of the number of SMUs results in considerable deterioration of the quality of soil cover representation;

3.for areas of diversified landscapes, the quality of soil cover representation of the young glacial period depends on the type of terrain morphogenesis.

In general, it turns out that the minimum number of SMUs for Poland should be approximately 60-65.

Introduction

Two terms have been specified for the European Geographical Soils Database: Soil Mapping Units (SMU) and Soil Typological Units (STU). The term ‘Soil Mapping Units’ refers to previous FAO activities which have been related to the Soil Map of the World (FAO-UNESCO, 1975) and corresponds to ‘Associations’, which were specified in the course of these activities. The term ‘Soil Typological Unit’ corresponds to the term ‘Soil Unit’ in the FAO classification.

These terms are described in the User’s Guide for the elaboration of the Soil Geographical Database of Europe (User Guide, 1995) in the following way:

a)SMUs are areas that can be identified and delineated on a map at the scale 1:1,000,000. They are geometrically defined by at least one polygon and are composed of at least one STU.

b)STUs are soil types that can be identified but not delineated within the SMUs due to insufficient resolution. An STU corresponds to a soil type homogeneous for all its characteristics (attributes).

The delineation of SMUs on the map is strongly related to landscape units.

During meetings of national co-ordinators of the European Geographical Soils Database, the number of SMUs for particular countries has been discussed in detail. All participants agreed that it is impossible to specify a number which would be suitable for every country (Varallyay, 1996). This number depends on the size of the country, heterogeneity of the soil cover and the associated number of STUs, the level of knowledge of the soil cover (details of the existing maps), applied methods of map editing, in particular the level of generalisation of contours of soil types, parent materials and texture.

For the recent version of the Soil Map of Poland at the scale of 1:1,000,000, which has been produced for the European Geographical Soil Database, the number of SMUs for Poland equals 51, and the average area of a SMU is 6040 km2.

Soil maps of Germany (70 SMUs and 5100 km2 per SMU) and Spain (24 SMUs and 6527 km2 per SMU) have been produced with a similar level of details.

More detailed elaborations have been produced, for example, for Belgium (31 SMUs and 977 km2 per SMU), the Netherlands (24 SMUs and 1415 km2 per SMU) and Luxembourg (12 SMU and 216 km2 per SMU).

After eliminating the factors which are related to the map editing process (as generalisation), a question arises, related to the logical relation between the homogeneity or diversification of the landscape and the number of SMUs. Such a relationship definitely exists. The measure of landscape inhomogeneity should be specified at first. Attempts to apply a logarithmic scale for the needs of evaluation of the level of diversification have been undertaken (Ibanez et al., 1995).

If a relationship between the level of landscape diversification and the number of SMUs exists, the optimum number of SMUs can be specified.

However, the question remains: what is the optimum number of SMUs for a map at the scale of 1:1,000,000? The optimum should provide an appropriate representation of the soil cover characteristics, with due consideration of the state of the art of the cartography.

In order to determine the optimum number of SMUs, four soil maps of Poland, produced in accordance with the FAO legend during the period 1971-1994, have been analysed.

They were the following maps:

CreatedAt scale SMUs

19711 : 1M 85

19721 : 1M38

19841 : 2M 19

19941 : 1M51

Map characteristics

The first version of the Soil Map of Poland for the future Soil Map of the World was produced in 1971. The Soil Map of Poland at the scale of 1:500,000 was the source material for this map. A Systematic Soils of Poland, in Polish and English, as well as comments on the FAO list of soil units to the Soil Map of the World at the scale of 1:5,000,000, was published in 1970. Soil units, newly introduced by the Systematic Soils of Poland, and corresponding units included in the FAO list, were of great interest.

These circumstances resulted in specification of numerous new units in the legend of the Soil Map of Poland, according to the FAO classification (the idea of SMUs did not exist at that time); the total number of units equalled 85; thus the number of specified units exceeded by 34 the number of units specified for the existing 1:500,000 map.

Co-ordinators of the Soil Map of Europe pointed out that this number was too large with respect to neighbouring countries and they recommended a decrease in the number of units. As a result, some similar units were merged. Unfortunately, the merging of units was of too large an order to reach the number of 38 units (although this number of 38 units was rather arbitrary).

Generalisation of the soil boundaries required for the new map with 38 units was also too radical. It did not consider characteristic features of landscape within various regions. As a result a map was produced which was too general, and the quality of representation of the soil cover in Poland was inadequate.

When it turned out that the Soil Map of Europe would not be published because of financial constraints, the authors published an extensive commentary to the FAO list of soil units and the map of scale 1:2,000,000 (Dobranski, 1984) which covered the territory of Poland. Only typological units were specified in the legend of this map, since parent materials, texture and typography could not be considered at this scale.

In 1992, when the decision to include Central and Eastern European countries in the European Geographical Soils Database was made, the Polish co-ordinator initiated works which aimed at amending the materials prepared in 1972 for the Soil Map of Europe. It became clear in the course of these works that, in practice, a new map should be produced that would meet the requirement of unification of attributes within STUs and that would better relate the SMUs to landscape characteristics. These new requirements could not be met using the map produced in 1972, because only 38 different soil map units are specified in it.

Thus a new map was produced in 1994 which identified 51 units. The Polish version of this map was produced at the same time for the National Atlas (Bialousz, 1994, 1995). After this map was completed, critical consideration of this map its utilisation for the MARS and CORINE projects, as well as for the harmonisation of border regions with neighbouring countries, was critically appraised.

It turned out that in selected areas of Poland, the level of detail of physical characteristic of soil and landscape attributes should be greater.

The question still remained: how many SMUs should be specified for Poland in order to represent the soil cover characteristics accurately?.

Analysis of maps

Portions of the four previous maps of Poland cover three distinctly different landscape types. These are:

mountainous landscape and old sedimentation basins in the south of the country;
areas of old glaciation, flattened as a result of periglacial processes and Holocene accumulation;
areas of young glaciation, with hills and the system of tunnel-valley lakes and fields of fluvioglacial accumulation.

Within the areas of mountainous landscape, Lithosols, Rankers, Dystric Cambisols, Calcaric Cambisols and Fluvisols SMUs are found. Within the old sedimentation basins, the dominant soils are Rendzinas and Haplic Phaeozems.

The area is almost lithologically uniform in the mountainous part (Flysh and granites). The number of SMUs is determined by the slope patterns and the density of river valleys.

The smaller number of SMUs employed on maps produced in 1972 and 1984 did not therefore result in any considerable loss of detail in the representation of soil cover for these areas. The main differences in the 1994 representation are the result of generalisation in river valleys. This also resulted in a decrease in the number of areas of Fluvisols on the maps which were produced in 1972 and 1984.

In the case of old sedimentation basins, the main factors which influenced the soil cover are the geological formation of calcareous rocks and the level of loess cover.

As in the mountainous areas, differences in the representation of loess cover results mainly from the generalisation of boundaries.

Thus, for the areas located within this part of Poland, which are characterised by clear landscape units, the number of SMUs is similar on all maps and the representation of the soil cover was mainly influenced by generalisation of river valleys.

Within the areas of old glaciation the landscape characteristics are mainly influenced by glacial, proglacial and contemporary river valleys, wide fluvioglcial and glacial terraces and flat areas located between river valleys with dense and random drainage systems.

Parent materials of the soils are sands, sands over loams, sandy loams and thin layers of silts over sands or loams. The parent materials and texture of soils show considerable variation within these areas.

Cartographic units which influence the soil cover characteristics are:

1.Fluvisols, Fluvic Gleysols, Gleysols and Histosols in proglacial and contemporary river valleys,

2.Stagnogleyic Luvisols, Podzoluvisols and Leptic Podzols within areas located between river valleys,

3.Leptic Podzols and Orthic Podzols, within areas of fluvioglacial accumulation.

European Soil Bureau  Research Report No. 4

The number of units, distinguished in particular maps, was as follows:

SMU / Number of SMUs on analysed maps
1971
(85 SMUs) / 1972
(38 SMUs) / 1984
(19 SMUs) / 1994
(51 SMUs)
Lithosols / 3 / 2 / 1 / 2
Rankers / 1 / 1 / 1 / 2
Dystric Cambisols / 3 / 1 / 1 / 2
Calcaric Cambisols / 2 / 1 / 1 / 1
Fluvisols / 2 / 1 / 1 / 2
Rendzinas / 3 / 2 / 1 / 3
Haplic Phaeozems / 1 / 1 / 1 / 1

The number of SMUs, distinguished in particular maps, is as follows:

SMU / Number of SMUs on analysed maps
1971
(85 SMUs) / 1972
(38 SMUs) / 1984
(19 SMUs) / 1994
(51 SMUs)
Fluvisols / 2 / 1 / 1 / 2
Fluvic Gleysols / 2 / 1 / 1 / 1
Gleysols / 4 / 1 / 1 / 3
Histosols / 2 / 1 / 1 / 2
Stagnogleyic Luvisols / 8 / 3 / 1 / 5
Podzoluvisols / 14 / 6 / 1 / 5
Leptic Podzols / 8 / 2 / 3
Orthic Podzols / 3 / 1 / 1 / 2

European Soil Bureau  Research Report No. 4

For these areas, five SMUs for Stagnogleyic Luvisols, five SMUs for Podzoluvisols and three SMUs for Gleysols are considered as almost sufficient for a 1:1,000,000 scale map.

However, it is necessary to increase the number of SMUs for Fluvisols, Fluvic Gleysols and Leptic Podzols, since, for the current number of SMUs, it is impossible properly to represent per-cent changes of STU within corresponding SMU.

Fourteen SMUs for Podzoluvisols, which were distinguished in 1971, seems too large a number.

Diversification of cartographic representation of the soil cover for this area is not only the result of varying numbers of SMUs, but also of changes in interpretation of criteria for particular STUs and, to a considerably smaller degree, of generalisation of units.

In general, the representation of SMU groups of the same prevailing STUs is appropriate on maps produced in 1994, and the soil cover characteristics are represented properly by these maps, but in order to achieve better representation of the diversification of the various STUs, parent materials and texture, several new SMUs should be distinguished.

For areas of young glaciation (Vistulian), the main elements of the landscape are latitudinal belts of terminal moraines, hilly areas of ground moraines with random outflow and cavings without outflows. These remained after the outflow of waters from dead ice filled longitudinal gullies with water and glacial sands, as did the large fields of fluvioglacial sands located in the south around terminal moraines.

High horizontal and vertical diversification of parent materials, soils and texture occurs. The main characteristic typological units for this area of Poland are Cambic Arenosols, Eutric Cambisols, Stagnogleyic

Luvisols, Leptic Podzols and Histosols. The Orthic Podzols unit occurs at the Southern edge of the area, in uniform and poor fluvioglacial sands, in the final stage of deposition. River valleys are not clearly formed, so there are few Fluvisols.

European Soil Bureau  Research Report No. 4

The numbers of prevailing SMUs, distinguished in particular maps are as follows:

SMU / Number of SMUs on analysed maps
1971
(85 SMUs) / 1972
(38 SMUs) / 1984
(19 SMUs) / 1994
(51 SMUs)
Cambic Arenosols / 2 / 2 / 2 / 2
Eutric Cambisols / 3 / 2 / 1 / 2
Stagnogleyic Luvisols / 6 / 3 / 1 / 3
Leptic Podzols / 6 / 2 / 1 / 4
Orthic Podzols / 3 / 1 / 1 / 2
Histosols / 2 / 1 / 1 / 2

European Soil Bureau  Research Report No. 4

Spatial diversification of glacial sands, from which Cambic Arenosols and accompanying Calcaric Cambisols have formed, is relatively high. However, the two SMUs for the 1:1,000,000 scale is sufficient for this group, since these soils are associated with distinct geomorphological units.

On the map of 1994, the number of units representing the combination Be and Lgs is too low, since the three factors which results in variations – Be and Lgs percentage, class of slopes a and b, and textural classes 1,2,3 and 4 – accumulate.

Four SMUs within Leptic Podzols are sufficient, but two units within Orthic Podzols (one for flat areas and one for dune areas) do not allow consistent differentiation of other STUs.

Similarly, the two units within Histosols do not cover all variations.

For this landscape type, it is also very important that STUs of different morphogenetic features – and with various trophic characteristics and water relations – are not merged during generalisation. Otherwise, the belt system of landscape units will disappear, as happened on the map of 1972.

Conclusions

The number of 38 SMUs used on the map of Polish soils produced in 1972 is definitely too small for the proper representation of soil characteristics of Poland at the scale of 1:1,000,000. The generalisation of contours on this map is too generalised.

The number of 19 SMUs on the map of 1984 is almost optimum for the scale of 1:2,000,000. The number of 85 SMUs on the map of 1971 is close to the optimum for the majority of soil types, but it is too large for the following types: Luvisols, Stagnogleyic Luvisols and Podzoluvisols. The number of 51 SMUs on the map of 1994 allows proper representation of the soil cover for areas of distinct landscape diversification such as mountains and old sedimentation basins, but it is too small for areas of large vertical and horizontal diversification of soil parent materials and texture.

The results of this analysis and the efforts made to harmonize SMUs for border areas with those of surrounding countries indicate that the optimum number of SMUs for a soil map at 1:1,000,000 scale is 60-65.

European Soil Bureau  Research Report No. 4

References

Bialousz, S. (1994). Soil Map of Poland, 1:1,500,000. Genetic classification, in: Atlas of Poland, PPWK, Warszawa, 41.1

Bialousz, S. (1995). Soil Map of Poland, 1:3,000,000. Granularity, in: Atlas of Poland, PPWK, Warszawa, 41.2

Dobrzanski, B., Kuznicki, F. and. Bialousz,S. (1984). Criteria for distinguishing and physical approach to soils of Poland according to FAO classification. Annals of Agricultural Science, vol. 188, PWN, Warszawa

FAO-UNESCO (1975). Soil Map of The World at 1:5,000,000 scale. Volume I Legend. UNESCO, Paris, 62 pp.

Ibanez, I.I., De Alba, S. and Boixadera, J. (1995). The pedodiversity concept and its measurement: application to soil information systems. In: European land information systems for agro-environmental monitoring. D. King, R.J.A Jones and A.J. Thomasson (eds). EUR 16232 EN, 181-196. Office for the Official Publications of the European Communities, Luxembourg.

Jamagne, M. Le Bas, C., Berland, M. and EckelmanN, W. (1995). Extension of the EU database for the soils of Central and Eastern Europe. In: European land information systems for agro-environmental monitoring. D. King, R.J.A Jones and A.J. Thomasson (eds). EUR 16232 EN, 85-100. Office for the Official Publications of the European Communities, Luxembourg.

King, D.,.Burrill, A., Daroussin, J., Le Bas, C., Tavernier, R. and Van Ranst, E. (1995): The EU Soil Geographical Database. In: European land information systems for agro-environmental monitoring. D. King, R.J.A Jones and A.J. Thomasson (eds). EUR 16232 EN, 43-60. Office for the Official Publications of the European Communities, Luxembourg.

Kowalkowski, A., Truszkowska, R. and Borzyszkowski, I. (1994). The map of morphogenetic and soil regions of Poland at 1:500,000 scale, in: Proceedings of Scientific Commissions of the Polish Soil Society VIII-15, Warszawa.

USER GUIDE (1995). User’s Guide for the elaboration of the Soils Geographical Database of Europe, v.3.1, July 1995.

Varallyay, G. (1996). Comments on border harmonization during the Meeting in Graz (unpublished).