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
(<12,000 yrs B.P.), after the Weichselian
glaciation. Owing to rather weak development, the
soils have been nationally classified and mapped
according to texture and content of organic matter,
and little attention has been paid to pedogenic
classification. Therefore Finland is quite broadly
presented in the Soil Map of the World and in the
Soil Map of Europe. Finland is covered mainly by
maps of Quaternary deposits at different scales
(1:20,000-1:1,000,000). The Quaternary deposits
of about one third of the county have been mapped
at scale 1:20,000 while the map at scale
1:1,000,000 is the only one to cover uniformly the
whole country. During the last five years, the
national soil classes have been related to the FAO
and WRB systems and to Soil Taxonomy. In 2000,
work began to compile a new nation-wide map and
database about the Quaternary deposits and soils at
scale 1:250,000 to conform to the requirements of
the Georeferenced Soil Database for Europe. This
project is planned to be completed by the end of
2008.
Soil Classification
The national soil classification of Finland is based
on texture and organic matter (Aaltonen et al.,
1949). The soils are separated into three main
groups: till soils (moraine); sorted mineral soils
(gravel, sand, fine sand, silt and clay) and organic
soils, including mull (organic matter, 20-40%),
peat (organic matter>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
Status of soil mapping in Finland. Sippola and Yli-Halla
133
EUROPEAN SOIL BUREAU  RESEARCH REPORT NO. 9
purposes by the Agricultural Research Centre
started in the 1920s.
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
134
occurrence of fine-grained sediment layers and
wetlands as well as thickness of peat deposits are
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
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
Mn, mg dm-3
Mo, mg dm-3
Ni, mg dm-3
Zn, mg dm-3
Mean 1998
Change 1974 to 1987
1.00
8.3
1,436
111
202
13.1
25.0
493
0.59
0.08
0.64
0.36
4.5
742
58
0.06
0.98
3.0
Change 1987 to 1998
%
0.0 N.S.
+4 N.S.
+0 N.S.
+10
+2 N.S.
+16
+4 N.S.
%
+4
-9
+7
-2
+7
+22
+28
-1 N.S.
+62
+31
+19
+17
+32
+10
-2 N.S.
-5
+4 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
-4
+7
+15
+3
0 N.S.
-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.
Status of soil mapping in Finland. Sippola and Yli-Halla
135
EUROPEAN SOIL BUREAU  RESEARCH REPORT NO. 9
Figure 1: Maps of Quaternary Deposits in Finland
136
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.
Computerised methods for data handling
advanced techniques for preparing soil maps
databases are now available, and they
effectively be used for the production of
Status of soil mapping in Finland. Sippola and Yli-Halla
and
and
can
soil
137
EUROPEAN SOIL BUREAU  RESEARCH REPORT NO. 9
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.
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Status of soil mapping in Finland. Sippola and Yli-Halla