Status of Soil Mapping in Finland

EUROPEAN SOIL BUREAU ⎯ RESEARCH REPORT NO. 9 Status of Soil Mapping in Finland Jouko Sippola Markku Yli-Halla MTT Agrifood Research Finland, 31600 Jo...
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EUROPEAN SOIL BUREAU ⎯ RESEARCH REPORT NO. 9

Status of Soil Mapping in Finland Jouko Sippola Markku Yli-Halla MTT Agrifood Research Finland, 31600 Jokioinen, FINLAND

Introduction Soils of Finland have been formed quite recently (40%); and gyttja (a mixture of sedimentary organic and mineral material). Little attention has been given to developing a genetic classification, a decision to some extent justified on the grounds that the soils are young (formed in Quaternary deposits) and formed under rather cold conditions. This national classification serves the practical soil-related activities in Finland well but makes it difficult to present soil data from Finland in an international context.

During the last ten years, requests to supply information about the soils of Finland to the European Union using international classification systems have been frequently received. MTT Agrifood Research Finland (formerly Agricultural Research Centre of Finland) has provided the data on Finnish soils for the European Soil Map at scale 1:1,000,000 according to the FAO/UNESCO classification system (FAO, 1974). The material is based on data prepared for the Soil Map of the World project in the 1970s. Within the territory of Finland, the following classes of the FAO/UNESCO system (1974) are recognised: Orthic Podzols Dystric and Eutric Histosols Vertic and Dystric Cambisols Dystric Lithosols, Dystric Regosols Dystric and Vertic Gleysols Other Soils

49% 28% 7% 2% 1% 13%

More recent work suggests that Arenosols, consisting of weakly podzolised soils, also exist but are included as Podzols in the Soil Map of Finland. Regosols, consisting of silty soils with weakly developed B horizons, may occupy a larger area than previously expected. In turn, the area of Histosols may be less extensive than previously assumed, if the thickness requirement for organic horizon is strictly followed (Yli-Halla and Mokma, 2002). Data from typical soil profiles have also been supplied for the European Soil Profile Analytical Database.

Soil Mapping Systematic collection of soil information started in Finland in the late 1800s when the Geological Survey of Finland began mapping the Quaternary deposits. The mapping of soils for agricultural purposes by the Agricultural Research Centre started in the 1920s.

Status of soil mapping in Finland. Sippola and Yli-Halla

133

EUROPEAN SOIL BUREAU ⎯ RESEARCH REPORT NO. 9 The Geological Survey has published maps at scales of 1:100,000 and 1:400,000, and a summary map at a scale of 1:1,000,000. The Agricultural Research Centre published its early soil maps at 1:50,000 or 1:100,000 scales. Since the end of the 1940s, the scale of 1:20,000 has been used. In the maps of the Geological Survey, soil type to a depth of 1m is indicated whereas in agro-geological maps the soil type of the plough layer is primarily shown. In 1972, a collaborative committee representing the National Board of Survey, the Geological Survey of Finland and the Agricultural Research Centre of Finland, was formed and the mapping activities mentioned above were combined. Surveyors of the National Board of Survey were trained to collect soil information when updating the basic topographic maps. It was estimated that the entire country would have been surveyed within 30 years, at scale 1:20,000 or 1:50,000. Initially the joint work progressed rapidly, but in the 1990s, due to economic recession, the work was practically stopped and did not restart. Mapping of about one-third of the country was completed at scale 1:20,000 or 1:50,000 (Figure 1). About half the cultivated land, located mainly in the southern part of Finland, has been mapped for soil types. Printed maps were produced during the early years of soil mapping but nowadays the soil information is stored and retrieved in digital form, and maps are produced only for a specific area on demand.

New Project: 1:250,000 In the late 1990’s, the Geological Survey of Finland started to develop methods for a project to produce a new country-wide map and database of the Quaternary deposits of Finland at scale 1:250,000, using modern GIS techniques and utilising previous soil maps of different scales and numerous other data sources. The glaciofluvial deposits, till formations, sedimentation basins and geomorphological features are delineated using a digital elevation model (DEM). Other data include remote sensing data, digital orthophotos and topographic data. The geological soil data layers are combined using GIS-techniques and ArcMap software. The surface soil is mapped mainly by interpreting airborne geophysical data. The procedures have been developed within this project. With the help of the low altitude aero-geophysical electromagnetic and radiometric data, the occurrence of fine-grained sediment layers and wetlands as well as thickness of peat deposits are

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identified. The soil in the surface layer, and at the depth of one metre, are defined for each polygon according to Finnish soil classification system. The results generated this way are verified mainly using data on soil types obtained from soil testing of agricultural land and from forest soil surveys and with limited amount of field work. The FAO and WRB names are derived for the soils and the database will conform to the manual of ESB (European Soil Bureau, 2002). The production process has been briefly described by Talkkari and Nevalainen (2003). MTT Agrifood Research Finland, as a member of the ESB Network, is responsible for the FAO and WRB classification and for the production of the database according to the ESB manual. Finnish Forest Research Institute also produces and makes available information on forest soils. The results of soil samples analysed for the agricultural soil mapping and forest soil inventories are used as a source of data included in the database. The agricultural dataset consists of texture determinations of some 28,000 samples and plenty of basic chemical soil data, only part of which is currently in a digital form. Some soil profiles are also analysed during the on-going project. The project was actually launched in 2002 and is planned to be completed by the end of 2008.

Soil Monitoring Summaries of soil test results have been the most important datasets about the concentrations of macronutrients (except N), some micronutrients and the distribution of soil types in agricultural land. (e.g. Kähäri et al., 1987). The data have been based on samples sent by farmers to obtain recommendations for fertiliser use. The soils are not tested annually but commonly at 5-year intervals, and the annual mean values are drawn from samples of different fields. Because at least 80,000-100,000 samples have been analysed annually, it is assumed that the mean values are, however, representative and the trends reliable. A more systematic monitoring was started in 1974, when some 2,000 samples were collected from agricultural land all over Finland (Sippola and Tares, 1978). Samples were analysed for pH, organic carbon, calcium, lead, magnesium, nickel, phosphorus, aluminium, boron, cadmium, cobalt, chromium, copper, iron, manganese, molybdenum, sodium, strontium and zinc.

Status of soil mapping in Finland. Sippola and Yli-Halla

EUROPEAN SOIL BUREAU ⎯ RESEARCH REPORT NO. 9

Table 1. Means of chemical characteristics of agricultural soils (n=705) in 1998 and the changes between 1974-1987 and 1987-1998 Parameter

Mean 1998

Bulk Density, kg dm-3 Org. C, % Ca, mg dm-3 K, mg dm-3 Mg, mg dm-3 P, mg dm-3 S, mg dm-3 Al, mg dm-3 B, mg dm-3 Cd, mg dm-3 Co, mg dm-3 Cr, mg dm-3 Cu, mg dm-3 Fe, mg dm-3

1.00 8.3 1,436 111 202 13.1 25.0 493 0.59 0.08 0.64 0.36 4.5 742

Mn, mg dm-3 Mo, mg dm-3 Ni, mg dm-3 Zn, mg dm-3

58 0.06 0.98 3.0

Change 1974 to 1987

Change 1987 to 1998

% 0.0 N.S. +4 N.S. +0 N.S.

+4∗∗∗ -9∗∗∗ +7∗∗

+10∗∗∗ +2 N.S.

-2∗ +7∗

+16∗∗∗ +4 N.S.

+22∗∗∗ +28∗∗∗ -1 N.S.

+62∗∗∗

-5∗ +4 N.S.

∗∗∗

+31 +19∗∗∗ +17∗∗∗ +32∗∗∗ +10∗∗∗ -2 N.S.

%

-4∗∗ +7∗∗∗ +15∗∗∗ +3∗∗ 0 N.S.

+27∗∗∗ -2.0 N.S.

-12∗∗ +1 N.S.

-22.2∗∗∗

+22∗∗∗

pH (H20) 5.8 +0.18 units∗∗∗ ** *** t-test: = (P>0.05); =(P>0.01); =(P>0.001); N.S.=not significant

-0.04 units∗∗∗

*

The acid ammonium acetate extraction method at pH 4.6 (Vuorinen and Mäkitie, 1955) was used to extract macronutrients (except N) and the acid ammonium acetate-EDTA method (Lakanen and Ervio, 1971) for micronutrients (except Boron) and heavy metals. Boron (B) was extracted with hot water. Sampling was repeated in 1987 on a subset of the same fields (1,320 fields, Ervio et al., 1990) and in 1998 (705 fields, Mäkelä-Kurtto and Sippola, 2002). The results of these surveys show that soil pH remains at a low level (Table 1). There were some changes attributable to the abundance of liming (Table 1). Concentration of P has increased as a result of intensive use of fertilisers, but this trend will probably not be repeated in the next survey, owing to much decreased use of P fertilisers during the last 10 years. Concentration of water extractable boron had increased from 1974 to 1987, due to general use of boron-containing NPK fertilisers, but no more in the latter period, because the concentration in the fertilisers was adjusted.

The concentration of extractable soil copper increased by 32% in 1974-1987 and some more from 1987 to 1998. This is most likely due to increased copper fertilisation, strongly advocated by the fertiliser manufacturer. The same reason applies to the increase in zinc concentration in 1987-1998. Of the harmful elements, the concentration of cadmium increased due the use of cadmium-containing raw phosphate to prepare fertilisers in some of the years in the period 19741987. During 1987-1998 only low-Cd fertilizers have been used, and there is no marked change in the Cd concentration of soil. There are also other sets of spatial soil data of Finland such as those collected in the ICP Forest programme by the Finnish Forest Research Institute, Baltic Soil Survey and the FOREGS Geochemical Baseline Mapping Programme, the last two conducted by the Geological Survey of Finland. All these have been carried out only once, and, thus, they are baseline surveys at the moment.

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EUROPEAN SOIL BUREAU ⎯ RESEARCH REPORT NO. 9

Figure 1: Maps of Quaternary Deposits in Finland

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Status of soil mapping in Finland. Sippola and Yli-Halla

EUROPEAN SOIL BUREAU ⎯ RESEARCH REPORT NO. 9

Applications of Soil Data Land use planning by different authorities is currently the main user of soil data. Most of the current uses in Finland serve soil and water protection with soil data being combined with other environmental data such as land use, topographic and ground water information. Soil vulnerabilities to different threats have been derived by combining soil maps and information on the hydraulic conductivity of the particular soil types. This information is needed when, for example, allocating land for different industries, in land use planning in general and when approving or rejecting certain activities to be established in given areas. In these environmental assessments, soil information is used in combination with information on ground water reserves. The area of peatlands (peat layer>30cm) in Finland is 7.2 million hectares (15% of land area). Combustion for energy is the major use of peat, and there are large power plants utilising peat in Finland. In horticulture, peat is used as a growing medium in greenhouses. Mires have been identified from maps, and further investigated for the volume of peat. Thematic maps of the peat reserves have been prepared (Lappalainen and Hänninen, 1993). National inventories of sand and gravel resources have been made by the Geological Survey of Finland on the basis of maps of Quaternary deposits. Erosion risk and nitrogen leaching on a catchment scale have been modelled partly on the basis of 1:100,000 and 1:20,000 soil maps (Laine and Rekolainen, 1996) in Southern Finland and erosion and leaching risk maps have been prepared. In this approach, information from soil maps is combined with topographic and land use maps. In this way, the impact of different measures (e.g. establishment of riparian buffer zones, use of reduced tillage) on water quality and nutrient loading from agriculture has been assessed (Rankinen et al., 2001). Data on the different horizons of soil profiles have been used when modelling the transport of phosphorus and eroded material (Tattari et al., 2001) and pesticides (Seppälä and Yli-Halla, 2001) from agricultural land. This information is needed in the development and implementation of the AgriEnvironmental Support Programme under which farmers receive subsidies for carrying out measures to reduce agricultural loading of waters.

Acid sulphate soils cause acidification of coastal rivers particularly on the western coast of Finland, a problem that has been aggravated by intensified drainage. Acid sulphate soils have been identified in order to be able to assess the size of the problem and to direct the remedial measures in a costeffective way. The potential areas of acid sulphate soils have been identified from soil maps, and the areas sampled and studied in more detail. Examples of such inventories, utilising soil maps, include those of the Kyrönjoki catchment (Erviö, 1975) and the Sirppujoki catchment (Palko et al., 1985). Recently a national estimate of the area of acid sulphate soils was published (Yli-Halla et al., 1999). Agricultural uses of soil maps were important particularly in the 1940’s and 1950’s when new land was intensively reclaimed for agriculture. Soil surveys by the Agricultural Research Centre of Finland were started in order to identify potential agricultural land areas, thus facilitating an increase in agricultural production as the need arises. Soil information has also been used in crop suitability modelling, providing a guide to the most suitable crops for a given area. The environmental uses have almost surpassed the traditional agricultural uses of soil maps. The summaries of soil test results have been effectively utilised by the fertilizer industry to adjust the ratios of nutrients in the compound NPK fertilizers according to the changes of phosphorus and potassium in cultivated soils. Also the level of boron has been adjusted on the basis of the trends in soil test results. Existing soil information has been valuable in the selection of suitably representative sites for field experiments and knowledge of the properties and distribution of the soils has facilitated the uptake and application of research by the Extension Service. A range of agricultural management practices is required on the diverse soils of Finland.

Outlook There is an increasing need for soil data for environmental impact assessment. The authorities are often faced with the fact that sufficiently detailed soil information (particularly in digital form) does not exist in the area of interest. Better supply of soil data is required also as a consequence of the EU Thematic Strategy for Soil Protection and the forthcoming Directive on Soil Monitoring.

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EUROPEAN SOIL BUREAU ⎯ RESEARCH REPORT NO. 9 Computerised methods for data handling and advanced techniques for preparing soil maps and databases are now available, and they can effectively be used for the production of soil databases, if sufficiently verified and supported with measured data. The recently launched project to produce a map and database of soils and quaternary deposits at scale 1:250,000, conforming to the manual of the European Soil Bureau and expected to be completed by the end of 2008, will make soil data of Finland nationally and internationally more available.

References Aaltonen, V.T., et al. (1949). Maaperäsanaston ja maalajien luokituksen tarkistus v.1949. Summary: A critical rewiew of soil terminology and soil classification in Finland in the year 1949. J. Scient. Agr. Soc. Finland 21: 37-66. Erviö, R. (1975). Kyrönjoen vesistöalueen rikkipitoiset viljelymaat. Summary: Cultivated sulfate soils in the drainage basin of river Kyrönjoki. J. Scient. Agric. Soc. Finl. 47, 550561. Erviö, R., Mäkelä-Kurtto, R. and Sippola, J. (1990). Chemical characteristics of Finnish agricultural soils in 1974 and in 1987. In Kauppi et al. (eds.). Acidification in Finland, Springer-Verlag, Berlin. p.214-234. European Soil Bureau (2002). Georeferenced Soil Database for Europe, Manual of Procedures Version 1.1, European Soil Bureau, Scientific Committee. 172pp. FAO-UNESCO. (1974). Soil Map of the World. 1:5,000,000. Paris Kähäri, J., Mäntylahti, V. and Rannikko, M. (1987) Suomen peltojen viljavuus 1981-1985. Summary: Soil fertility of Finnish cultivated soils in 1981-1985. Viljavuuspalvelu Oy. 105pp. Laine, Y. and Rekolainen, S. (1996). Erosion control by riparian zones and nitrogen loss reduction by changing crop rotation in Finland. In: Regionalisation of erosion and nitrate losses from agricultural land in Nordic countries. TemaNord 615, 49-54. Lakanen, E. and Erviö, R. (1971). A comparison of eight extractants for the determination of plant available micronutrients in soils. Acta Agr. Fenn. 123, 223-232. Lappalainen, E. and Hänninen, P. (1993). Suomen turvevarat. Summary: The peat reserves of Finland. Geological Survey of Finland. Report of investigation 117.

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Mäkelä-Kurtto, R. and Sippola, J. (2002). Monitoring of Finnish arable land: changes in soil quality between 1987 and 1998. Agric. Food Sci. Finl. 11, 273-284. Palko, J., Räsänen, M. and Alasaarela, E. (1985). Happamien sulfaattimaiden esiintyminen ja vaikutus veden laatuun Sirppujoen vesistöalueella. (in Finnish, translation of the title: Occurrence of acid sulfate soils and their impact on water quality in the Sirppujoki catchment). Rankinen, K., Tattari, S. and Rekolainen, S. (2001). Modelling of vegetative filter strips in catchment scale erosion control. Agric. Food Sci. Finl. 10, 99-112. Seppälä, T. and Yli-Halla,M. (2001). Pesticide groundwater leaching modelling in risk assessment in Finland-interim report. Finnish Environment Institute. Moniste-Report 219. 99pp. Sippola, J. and Tares, T. (1978). The soluble content of mineral elements in cultivated Finnish soils. Acta Agric. Scand. Suppl. 20, 11-20. Talkkari, A. and Nevalainen, R. (2003). Georeferenced 1:250,000 soil database for Finland-an approach based on multisource geological and soil data. In: 4th European Congress on Regional Geoscientific Cartography and Information Systems: Geoscientific Information for Spatial Planning, Bologna, Italy, June 17th-20th 2003. 276-279. Tattari, S., Bärlund, I., Rekolainen, S., Posch, M., Siimes, K., Tuhkanen, H-R. and Yli-Halla,M. (2001). Modelling sediment yield and phosphorus transport in Finnish clayey soils. Trans. ASAE 44, 297-307. Vuorinen, J. and Mäkitie, O. (1955). The method of soil testing in use in Finland. Agrogeol. Publ. 63: 1-44. Yli-Halla, M., Puustinen, M and Koskiaho, J. (1999). Area of cultivated acid sulphate soils in Finland. Soil Use and Management 15:62-67 Yli-Halla M. and Mokma, D. (2002). Problems encountered when classifying the soils of Finland. European Soil Bureau Research Report 7: 183-189.

Status of soil mapping in Finland. Sippola and Yli-Halla

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