Soil Information and Soil Data Use in Slovenia

Transcription

1 Soil Information and Soil Data Use in Slovenia Borut Vrščaj, Tomaž Prus, Franc Lobnik Centre for Soil and Environmental Science, Biotechnical Faculty, University of Ljubljana Jamnikarjeva 101, SI 1000 Ljubljana, Slovenia Introduction Systematic soil mapping in Slovenia started in the 1960s, while collection of soil data started in 1930s (B. Vovk). In the late 1980s the Centre for Soil Science and Environment (CSES) started to establish the digital soil map of Slovenia. The work on soil mapping continued with several interruptions until the end of January 1999, when all the territory of Slovenia was included in an operative digital soil map at the scale 1:25,000 (DSM25). DSM25 represents the core of digital soil data brought together into the Soil Information System (SIS), providing a wealth of information on Slovenian soils. Beside DSM25 two important soil information layers associated with DSM25 are included in SIS: measured data on ~1,700 soil profiles (SP) and the soil pollution point data layer (SPP). Available Soil Data and Soil Protection Measures Most of the older soil maps have been classified according to the modified Yugoslav classification system (Škorić, Čirić, Filipovski; cit. in Škorić, 1986). Several names of the soil systematic units have been introduced according to Stepančič & Ažnik (1976). Stritar (1990) presented soil associations for the needs of urban planning in the early 1980s as an approach based on natural regions, landscape appearance and soil. In that system, soil sequences or pedosequences, determined on the basis of parent material, have been mapped at the scale 1:5,000 together with land categories, developed according to the land capability classification of Klingebiel and Montgomery (1961) with certain modifications necessary for Slovenian conditions (Stritar, These maps were very important for protection of agricultural (specially arable) land. Class 1 and 2 agricultural land are included in a special planning zone called best agricultural land, with very limited possibilities for nonagricultural land use change, defined also in the latest law on agricultural land (Official Gazette RS No.59, 1999). Land categories were introduced into the system of agricultural land protection at the time when soil information was not sufficient and large-scale soil maps were not available for the whole Slovenian territory. Therefore, land categories were not founded on concrete soil data; consequently certain discrepancies in the land use planning process appeared. A new categorisation based on soil data is necessary, and preliminary tests on using digital soil information for elaboration of new categorisation have already been undertaken. The Slovenian Soil Classification The Yugoslav classification system was officially used in Slovenia until However in practice, this system has been modified in many cases, as mentioned before. The need for a comprehensive classification system has been recognised with the start of systematic digitisation and preparation of the attribute tables To accommodate this, the solution was a provisional Slovenian soil classification system, which has been upgraded several times during the process of digitisation. A parallel conversion of soil systematic units according to the revised legend of the Soil Map of the World, 1988, has been applied in this system. Soil types and their distribution The system is basically genetic, hierarchical and mostly influenced by the ideas of Kubiena. Four major groups are distinguished on the basis of presence of water, soil permeability and salt presence. 331

2 They are Terrestrial (automorphic) soils, Hydromorphic soils, Salt affected soils and Submerged soils. The two latter groups are present due to the marine coast and several larger lakes but no soil profile has been described yet. The less developed soils are raw soils such as Lithosols (Lithic Leptosols), Regosols and Colluvial (deluvial) soils. Rendzinas (Rendzic Leptosols), thin soils with A-C or A-R profiles, are the most widespread soil type in Slovenia covering about 24% of the mapped territory. They form on limestone and dolomites, which cover almost half of Slovenia (44%), and on other rock derived parent materials. Rendzinas are classified in much detail and Rankers (Dystric Leptosols) are relatively rare (4%). Soils with a developed cambic B-horizon are included in the class of Cambic soils. Further division is made on the basis of parent material. In a word-for-word translation from the Slovenian language, they are called brown soils overlying hard carbonate rocks and terra rossa (both Chromic Cambisols), which cover 14% of the Slovenian territory, eutric brown soils (Eutric Cambisols, 14%), and dystric brown soils (Dystric Cambisols, 16%). Eutric Cambisols, often found on the bottom of basins and valleys or in terraced hilly regions, make the most fertile Slovenian agricultural land. Leached varieties of Chromic Cambisols and Luvisols are less widespread, but can be found on limestone and dolomite as well. On siliceous parent materials, Podzols are an extremely rare soil type. The group of terrestrial soils has also one class containing arable man-modified soils with the soil types, Rigosol and Hortisol (Aric and Fimic Anthrosols, and deposited man-made soils, such as, for example, on municipal deposits (Urbic Anthrosols), cover 1.6% of Slovenian territory. Hydromorphic soils can be found in tectonic basins and flat areas. Eutric, Dystric and Calcaric Fluvisols are common along the rivers and cover more than 5% of Slovenian territory. Other Hydromorphic soils are also common in these areas, covering almost 9% of Slovenia. Eutric and Dystric Pseudogleys (Planosols) are soils with periodical surplus of surface water originating directly from the atmosphere. Gley soils (Gleysols) are characterised by seasonal water surplus originating from the shallow groundwater table. If floodwater or water collected in a local catchment is added to that soil surface, an amphigley soil is developed. Peat or organic soils (Histosols) are distinguished as lowland peat soils, upland peat soils and transitional peat soils. The group of Hydromorphic soils is also includes the class of man-modified soils. Ameliorated soils to which a drainage system is applied are the only representative. Soil Survey in Slovenia Systematic soil mapping at the scale 1:25,000 began in Slovenia in 1963 when Slovenia was a republic of the Federal Republic of Yugoslavia. Numerous soil profile data were collected and several soil maps were published in paper form. In 1981, the initial mapping scale at 1:50,000 was changed to 1:25,000. By the end of 1986, about 50% of Slovenian territory had been covered with soil maps, partly at scale 1:50,000 and partly at scale 1:25,000. Only a few map sheets were published on old military topographic base maps, others existed as manuscripts and soil profile data as typescripts. Three soil maps on new, 1:50,000 scale topography were published between 1984 and 1986: parts of Ljubljana, Murska Sobota and Ptuj. Each of them was accompanied by a booklet containing soil descriptions, information on basic soil properties, representative soil profile, measured data and land use information. The first digital soil data in Slovenia were captured by CSES in the early 1970s. The design of databases and the definitions of attributes were standardised as a part of the federal project, Pedological Information System of Yugoslavia (PIS, 1978). The data were centrally maintained in a computer centre in Sarajevo. The PIS did not include maps; the computer systems were not capable of storing digital maps so the maps were stored in paper form. The fate of this information base is not known, but it is very likely that the digital and papers records were lost during the war in Bosnia and Herzegovina. The majority of information input to PIS by CSES remained preserved in archives, though later this information was revised and stored in electronic form. Rapid development of geoinformatics in the 1980s enabled the project 'Digital Soil map of Slovenia at the scale of 1:25,000' to begin in

3 Figure 1: Digital soil map of Slovenia at 1:25,000 scale, generalised according to the FAO classification. The project was initiated by CSES (Lobnik, Vrščaj, Prus) and financed through various research works by the Ministry of Science and Technology. The core of the project was digitisation of soil maps and associated information into a GIS system. After achieving independence in 1992, it was decided in Slovenia that the work on mapping soils, digitisation of soil data and the establishment of digital soil databases should be accelerated. In 1992, a new contract was made between the Ministry of Agriculture, Food and Forestry of Slovenia (MAFFS) and CSES. The project had the following major goals: Complete soil mapping in the scale 1:25,000; Design digital soil map as a contemporary GIS layer; Elaborate digital soil map; Collect, verify and enter soil profile data into the databases. Soil mapping was divided into 200 sheets based on 1:25,000 scale topographic maps (TM25). Each TM25 map covers approx. 13,000ha. Between 1992 and 1998, the additional soil survey fieldwork was carried out simultaneously with computerisation of the data. The project was completed in January 1999, when a unified, seamless Digital Soil Map at scale 1:25,000 (DSM25) for the whole of Slovenia was available (Figure 1). Soil Information System Besides soil mapping, many different research projects concerning soil and soil pollution have been accomplished in Slovenia. Altogether these have resulted in a large amount of data that has to be organised and used in the most effective way. The data have to be stored in an adequate geographic information system. At the present time, the soil data available in digital form are brought together into the Soil Information System of Slovenia (SIS), initiated, developed and maintained at CSES (Vrščaj and Prus 1994; Vrščaj 1996, Vrščaj,et al., 1998). The SIS is not directly financed by the state but is operated through ongoing research projects. The basic goal of SIS is to unite this geographically defined soil data into an easy-to-serach and, through computer communications, easy-to-access entity. It is a comprehensive source of soil data, verified and comparable with respect to laboratory analyses, procedures and spatial accuracy. SIS represents a basis for further investigation in soil, environmental, and soil-related sciences using GIS tools and methods. 333

4 SIS unites the following main layers into a logical whole: Digital Soil Map at scale 1:25,000 (DSM25) and associated soil attribute databases: Soil Profiles (SP); Soil Pollution Monitoring (SPM). Following recent soil survey and soil monitoring, new data, new software and users needs ensure that SIS development is ongoing. The applicability of DSM25 The Digital Soil Map, at scale 25,000, was designed as the basic reference base of Slovenian soils as a natural resource. The resolution of databases enables spatial analyses and their use at state, regional and sometimes even at county scale. It was designed for use at the scales 1:50,000 to 1:20,000. Scales of 1:100,000 and smaller (state level) require the generalisation of DSM25. When used at a scale larger than 1:10,000 or 1:5,000, the data are used as a rough (but still useful) approximation and are supplemented with additional data. The attribute component of the DSM25 database is constantly being improved in various research projects. The pedologists/field soil surveyors, who work on soil mapping, are enriching the DSM25 attribute dataset with expert knowledge about basic soil properties. Yet in the future, it is intended to improve the sometimes subjective expert opinion using statistical and geostatistical approaches. Currently, the DSM25 graphical and attribute information are repeatedly used in different projects at CSES, mostly financed by state institutions. Recently, the increasing use of GIS tools and procedures by land use planners, civil engineers, scientists, local communities, and students, has increased the demand for DSM25 data. The DSM25 structure DSM25 incorporates spatial and attribute information; thus it is truly a GIS information layer. Graphic information is represented by soil mapping unit (SMU) polygons with the properties described in attribute tables. From a technical point of view, DSM25 is organised into a computer map library of 200 sheets. The basic objects of the maps are the SMU polygons. Each SMU is composed of up to three different soil types named soil-systematic units (SSU), which cannot be shown separately because of the scale or because they appear in the same soil series. In addition to the three main SSUs, another SSU can be entered into the SMU attribute table. This is described as an inclusion. The total area of the inclusion soil type does not exceed 10% of SMU area. The SSU is a soil type with typical characteristics that are fundamentally different from characteristics of other soil types (other pedo-systematic units). SSU properties are described in attribute tables maintained by a computer relational data base management system (RDBMS) (Figure 2). Figure 2: DSM25 attribute data; the design of SQL query, MS SQL 2000 environment. 334

5 For modeling purposes, the DSM25 information is rasterised into separate grids, on the basis of attribute data, for use in raster GIS systems. Raster grid modeling enables the use of unlimited additional soil and non-soil spatial information in raster form. Inside the DSM25 GIS layer, two major attribute datasheets are linked using the relations between SMU and SSU databases. The first one is closely connected to the graphic SMU polygon data. The SSU database contains the data on soil type (SSU) properties and the SMU soil properties can be calculated from individual SSU properties using different models. Supplementing spatial databases The structure of the DMS25 is adapted to the relatively rich GIS data sources available in Slovenia, which are constantly improved. The separate soil-related spatial information allows its flexible use in a GIS environment. The most important or most frequently used spatial information at CSES is the following: Digital elevation models. Data on terrain are not a part of the DSM25 attribute data set. The relief information (elevation, slope, aspect) originates from three different available digital elevation models (DEM) at resolutions 100m, 25m and 20m; all of them covering the whole of Slovenia. Land use information in Slovenia is available at two scales: CORINE Land Cover for Slovenia 1:100,000 vector database, EC-Phare project (Kobler and Vrščaj, 1998) and the recently completed vector database Land use 5,000, a GIS database at the scale 1:5,000 financed by MAFF. Information on parent material is available from a rectified scanned map of 1:1,000,000 scale (Institute for Geology and Geotechnics, Ljubljana). The new geological vector database is being prepared. Until now, the 30-year average precipitation data (Kastelec, 2000) in 100m GIS grid format, the potential evapotranspiration (Kastelec, 2002) and estimated water surplus on the soil surface (Kastelec, 2002) have been available to the CSES. In the models some data for microclimatic conditions are derived using DTM. Figure 3: Locations of soil profiles. 335

6 Figure 4: Standardised SIS report: Page 1: soil profile description; Page 2: brief interpretation for non-soil scientists Measured Parameters: Soil Profile data A soil profile is a vertical cross-section of a soil type from the surface to the parent material. It is representative of a soil type (SSU), and it is geographically oriented by x, y and z co-ordinates. A soil profile point layer contains data on physical and chemical soil properties obtained by standard soil analyses. Thus, SP/PP contains the attribute data for a SSU in a certain location. By the end of January 1999, the data from approximately 1,700 soil profiles had been compiled. The work is not finished yet, as apparent from Figure 3, and there are still some areas for which measured soil data are not available The soil profile point layer is related to the attribute databases containing: The description of the profile site; Field descriptions of soil profile horizons (Figure 4); The standard soil laboratory analyses of soil profile horizon samples. Soil Pollution Monitoring The Soil Pollution (SP) layer contains the point data of concentrations of several organic and inorganic pollutants in soils. The soil sampling pattern performed on predefined sampling locations is standardised and defined by legislation (Official Gazette RS, 1997). One sampling point represents the centre of the 100m circle with six sub-sampling locations. From each, samples are taken at three different depths (0-5cm, 5-20cm and 20-30cm) and combined into three representative samples. In addition to soil samples, the tissues of the test plant (Plantago lanceolata - narrow leaf plantain) are sampled in and around the circle and analysed (Hudnik et al., 1994). Predefined sampling in regular grid covers the complete state territory. The density of sampling points is 2km x 2km in agricultural areas while forests and high-elevated areas are covered with a 4km x 4km grid. In areas where there was anticipated to be contamination of the soil by heavy metals and pesticides, denser sampling was performed on a 1km x 1km grid in the late 1980s and early 1990s (Celje County, parts of the Ljubljana, Jesenice, Dravsko - Ptujsko Polje, Krško Polje and Region 336

7 of Koper - Figure 5). Since July 2002, soil pollution data on 367 sampling have been stored in the SIS and available, interpreted according the legislation (Official Gazette RS, 1996). In 1998, a new project financed by the Ministry of Environment and Physical Planning started. The aim of the project is to establish monitoring of soil pollution on selected predefined points for the whole of Slovenia. Sampling location point attribute data consist of: Co-ordinates of the point and site description data; The concentrations of inorganic substances in soil samples (heavy metals); The concentrations of organic substances in soil samples (pesticides, PCB...). The concentrations of heavy metals are determined in the test plant Plantago lanceolata - narrow leaf plantain. Applications of SIS data Because of the increasing availability of GIS tools, the demand for soil data is growing among land use planners, state institutions, civil engineers and students. The main projects through which the applicability and the advantages of the digital soil map data set were tested are described in the following sections. Land suitability for agriculture The results of this project are six raster databases at 100m resolution. Each of them represents the spatial information on suitability for certain agricultural use: arable land, vineyards, orchards, hops, grassland, and olive growing. A computer model was made for each database. The elaborated maps show the suitability of the land for the particular agricultural use. They were used in land use planning on at the state level. Areas affected by drought in A GIS raster model was designed to elaborate the raster (100m resolution) database of soils affected by severe drought in the year Beside DSM25 polygons, basic model input information was: soil parameters (water retention capacity), expert classification of soil systematic units and precipitation data, DEM 100m. Soil pollution Monitoring of soil pollution in Slovenia is described in (Lobnik et al., 1992, 1994; Zupan et al., A case study of soil and plant pollution in industrial areas in Slovenia is described in (Hudnik et al., 1994, Prus and Vrščaj 1994, Lobnik et al., 1994). An SIS report is shown in Figure

8 Figure 5: Predefined sampling locations according to the land use and elevation. Red dots: locations of 367 sampling points with data available in SIS. Page 1: data on sampling location Page 2: soil description, short interpretation Page 3: Heavy metal concentrations interpreted according to the national legislation Page 4: Organic substances, some of them interpreted according to the national legislation Figure 6: Standard SIS four-page report on soil pollution at certain sampling points 338

9 Figure 7: Suitability of land for agricultural production. Dark green - very suitable; pale yellow - marginal agricultural land. Natural limitations for agriculture The raster database at 100m resolution shows the areas with limited capability for agricultural production. A GIS raster computer model was developed, with the basic input data being DSM25 polygons, DSM25 attribute data, soil-type suitability for agriculture (expert classification attribute data), DEM at 100m resolution (slope, aspect) and 30-year average precipitation data (see Figures 7 & 8). Nitrate leaching The problem of nitrate leaching in Slovenia is being evaluated in an ongoing project financed by Ministry of Environment and Spatial Planning. DSM25 with derivatives and data on actual agricultural practice are used as most important input data. Preliminary results (Figure 9) show that potential ground water pollution is high in places with permeable soils and where the good agricultural practice is not respected. National Irrigation Programme The proposed irrigation areas in Slovenia were analysed and classified according to 6 soil properties. As a result, 65 maps were plotted in which the soil suitability for irrigation was shown in 5 categories. A map of water holding capacity is shown in Figure 10. Highway construction The proposed routes for several highway sections were evaluated: Arja vas - Vransko, Blagovica - Šentjakob, Cogetinci - Radmožanci, and Vipava Valley. The loss of soils in the intensive agricultural areas and environmental impact on agricultural production have been estimated (Šporar et al, 1990, 1991; Prus, 1996; Rupreht et al., 1994, 1995). Important Digital Maps At CSES several different soil and soil/land related digital maps have been completed with the help of DSM25: Soil map of Slovenia at the scale of 1: 400,000; Soil Map of Europe 1:1,000,000 - Slovenia; Soil map, 1:5,000 -areas of detailed projects; Land Cover /Land Use - Phare, Corine projects; Work in Future vs. Needs The future work is extensive and must focus on multi-functionality and applicability of data with the emphasis on the needs of the end-user who is often not a soil scientist. In reality much will depend on appropriate financial support but existing soil information should be adapted/enhanced to: 339

10 Answer the national and European needs to protect landscapes; Reduce any kind of land degradation; Maintain soil quality and sustainability of soil and land; Serve the end-users better. The following work is needed in the future: Improve and adapt existing soil information - soil maps to enhance the applicability and multifunctionality of data; Derive important basic soil parameters as separate datasets at a resolution suitable to be used at the county / watershed / landscape scale; Develop a set of pedotransfer functions to cover air and water related soil properties and to implement them in GIS modelling; Improve the spatial resolution and accuracy of DSM25 using high resolution DTM and EO data and new modelling techniques; Enrich the soil datasets with new data; Establish a very detailed national soil classification system, which is necessary for land use planning; Study, in detail, forest ecosystems as well as certain studies in the field of agronomy; Develop the possibility of converting national classification into world-wide systems; Explain certain phenomena in soil genesis which do not fit with known environmental conditions; Popularise and enhance knowledge about the significance of the soil as a natural phenomena and the dependence of humans on soil. Figure 8. Evaluation of agricultural land according to the suitability for arable land - for two neighbouring counties. The histograms show the hectares of best arable land (dark brown) and less suitable agricultural land (pale yellow). 340

11 Figure 9: Preliminary results of potential pollution of ground water with nitrates Green - no risk Brown - very high risk. Figure 10: Water holding capacity of soil of agricultural land in Slovenia. The printout from the raster database 341

12 Figure 10: Evaluation of proposed highway routes; section Zadobrova-Blagovica. Cd in soil (0-5cm) Zn in soil (0-5cm) Pb in soil (0-5cm) Figure 11: Celje County case study. Soils polluted with Cd, Zn and Pb according to the national legislation. 342

13 References Definition of areas with natural limitations for agriculture, Investigation Report for Ministry of Agriculture Food and Forestry of Slovenia, Centre for soil and Environmental Science, Maj Hudnik V., Zupan M., Lobnik F., Kozak-Legiša Š. (1994). Bioavailability Assessments of Cd, Zn and Pb in Polluted Soils with Indicator Plant Plantago lanceolata L., Biogeochemistry of Trace Elements, A special issue of Environmental Geochemistry and Health, Volume 16, University of Bradford, UK, 1994, p Kastelec, D. (2000, 2002). 30 year average precipitation data, 1km and 100m grid databases. Kastelec, D. (2002). Estimation of average water surplus on the soil surface, 100m grid database. Kastelec, D. and Bergan, T.K. (2002). Potential evapotranspiration (Thornweit method) 30, 100m-grid database. Klingebiel, A.A. and Montgomery, P.H. (1961). Land capability classification. USDA Agriculture Hand Book No.120. Kobler, A. and Vrščaj, B. (1998). Corine Land Cover Slovenia GIS database - Current status, Phare, International Conference on GIS for Earth Science Application (ICGESA), Ljubljana, Maj. Lobnik, F. et al., (1989). Tematska karta onesnaženosti zemljišč celjske občine. BF Agronomija, Ljubljana, A3, 159pp. Lobnik, F. et al., (1992). Monitoring onesnaženosti tal in vegetacije v Sloveniji, BF Agronomija, Ljubljana, 322pp. Lobnik, F., Zupan, M., Hudnik, V. and Vidic, N.J. (1994). A Soil and Plant pollution Case Study in an Industrial Area in Slovenia. Environ Geochem Health 16, Official Gazette RS. (1996). Decree on limit, alarm and critical values of hazardous substances in the soil. Official Gazette RS No. 68/96 Official Gazette RS. (1997). Rules on operation monitoring of the input of hazardous substances and plant nutrients in the soil Official Gazette RS No 55/97 PIS. (1987). Pedološki Informacioni Sistem Jugoslavije, Kodni Priručnik, may (Pedological Information System of Yugoslavia, Coding book) Prus, T., Šporar, M., Rupreht, J., Vrščaj, B. and Tič I. (1996). Primerjalna študija poteka tras AC na osnovi presoje vplivov na tla kot sestavnega dela okolja in valorizacije pridelovalnega potenciala kmetijskih zemljišč za odsek Cogetinci- Radmožanci, Študija za izbor variante, marec, 28pp. Prus, T. and Vrščaj, B. (1994). Application of soil information system in the national project of irrigation in Slovenia. Fifth European Conference on Geographical Information Systems EGIS/MARI'94, Paris March-April, p Prus, T. and Vrščaj, B. (1997). Use of Soil Information System in the environmental impact assessment of highway construction in Slovenia, Third European Conference on Geographical Information, Vienna, Austria, April 16-18, p Rupreht, J., Prus, T., Vrščaj, B., Šporar, M., Knapič, M. and Kočar, I. (1994a). Presoja vplivov na tla kot sestavni del okolja z valorizacijo pridelovalnega potenciala kmetijskih zemljišč za avtocestni odsek Arja vas - Vransko, Variantni pododseki: Južna, V1, V2, januar, 25pp. Rupreht, J., Prus, T., Vrščaj, B., Šporar, M., Knapič, M. and Tič I. (1994b). Presoja vplivov na tla kot sestavni del okolja z valorizacijo pridelovalnega potenciala kmetijskih zemljišč. Detajlna študija za odsek Šentjakob-Domžale, marec, 9pp. Rupreht, J., Šporar, M., Prus, T., Vrščaj, B., Knapič, M. and Kočar, I. (1994c). Presoja vplivov na tla kot sestavni del okolja z valorizacijo pridelovalnega potenciala kmetijskih zemljišč za odsek avtoceste Razdrto-Vrtojba; pododseki Razdrto-Vipava, Vipava-Skrilje, Skrilje-Selo, Poročilo, november, 32pp. Škorić, A. (1986). Postanak, razvoj i sistematika tla, Sveučilišna naklada, Zagreb, 171pp. Šporar, M. and Rupreht, J., s sod. (1990). Pedološko kartiranje SR Slovenije in raziskovanje tal, List Gorica, URP: C : Ekologija - Pedologija, Ljubljana Šporar, M. and Rupreht, J., s sod. (1991). Pedološko kartiranje SR Slovenije in raziskovanje tal, List Postojna in list Bovec, URP: C : Ekologija - Pedologija, Ljubljana Stepančič, D. and Ažnik, M. (1976). Rendzina v Sloveniji. Zbornik Biotehniške fakultete UL, Ljubljana 343

14 Stritar, A. (1990). Krajina, krajinski sistemi, Raba in varstvo tal v Sloveniji, Partizanska knjiga, Ljubljana, 173pp. Vrščaj, B. (1996). Izdelava modela podatkovnega segmenta talnega informacijskega sistema. Biotehniška fakulteta, Ljubljana, Graduation thesis Vrščaj, B. and Prus, T. (1994). Soil Information System (SIS/TIS) in Slovenia, Fifth European Conference on Geographical Information Systems EGIS/MARI'94, Paris March-April, p Vrščaj, B., Prus, T. and Lobnik, F. (1998). The Soil Information System of Slovenia. International Conference on GIS for Earth Science Application (ICGESA), Ljubljana, Maj Vrščaj, B., Zupan, M. and Lobnik, F Računalniška obdelava podatkov v projektu Tematska karta onesnaženosti tal in zemljišč celjske občine, Zbornik Biotehniške fakultete, supl,13, str 41 do 58. Vrščaj, B., Zupan, M. and Lobnik, F. (2002). Data on soil pollution in urban planning. 17th Congress of Soil Science, Bangkok. Zupan, M., Hudnik, V., Lobnik, F. and Kadunc, V. (1995). Accumulation of Pb, Cd, and Zn from contaminated soil to various plants and evaluation of soil remediation with indicator plant (Plantago lanceolata). In Contaminated Soils: Third International Conference on the Biogeochemistry of Trace Elements, Paris, (ed. Prost R.), D:\data\communic\086.PDF, colloque 85, INRA Editions, Paris, France. 344