1.2

Sweden

Barbro Ulen

Division of Water Management, Department of Soil Sciences, Swedish University ofAgricultural Sciences, Box 7014, SE-750 07 Uppsala, Sweden

1.2.1 INTRODUCTION

Sweden is situated in northern Europe between latitudes/longitudes 55–69� N and 11–24� W. The country

borders the Baltic Sea, Gulf of Bothnia, Kattegeat and Skagerak and has borders of 1619 km with Norway in

the west and 586 km with Finland in the north. The climate varies from subarctic in the north, where it is

influenced by the Gulf Stream, to maritime and continental in the south. In the north, the winters are long,

lasting 8–9 months, whereas in the south, they are short and the soil does not freeze every year. Precipitation in

the north and along the Norwegian border and the south-west coast ranges from 600 to 1500 mm annually. In

the east, precipitation seldom exceeds 700 mm annually.

Arable soils are mostly clayey, namely clay loam or other forms of loam. Soils with 25–40% clays are

defined as medium clay soils and soils with more than 40% clays are defined as heavy clay soils. However,

only limited areas have heavy clay soils (Figure 1.2.1). The soil consists of glacial and post-glacial

sediments of different origin and characteristics. The dominant soil type along the coast of the northern and

western coasts is fine silt (Figure 1.2.2). Heterogeneous clays dominate the eastern part of the country, but

there are also lowland areas with silt clay. In the mountainous forest and valley districts of southern

Sweden the soil is till derived from Archaean bedrock. In Scania and the islands the most common soil type

is clay or loam, but there are also fine-textured soils (Steineck et al., 2001). The most common mineral in

these clay soils is illite. In Scania there are also smectites, and in coastal areas of the west of the country

‘quick-clays’.

Soil Erosion in Europe Edited by J. Boardman and J. Poesen# 2006 John Wiley & Sons, Ltd. ISBN: 0-470-85910-5

1.2.2 ENVIRONMENTAL CONCERN

Eroded particles are carriers of phosphorus (P) and other pollutants to surface waters and environmental

concern about erosion is primarily over eutrophication. In addition, large amounts of suspended solids may

cause poor light conditions in surface water that will favour Cyanobacteria and disturb fish breeding. A

significant amount of the particles may be in colloidal form (Ulen, 2003).

The total phosphorus (TOTP) status of inland waters has recently been surveyed (Johansson and Persson,

2001). Most of the eutrophic lakes are situated in the agriculturally dominated southern and central plain areas.

Figure 1.2.1 Clay content (%) of Swedish agricultural topsoils. (Reproduced with permission from Eriksson J,

Andersson A, Andersson R. Texture of Agricultural Topsoils in Sweden. Report 4955, Swedish Environmental Protection

Agency, Stockholm, 1999)

18 Soil Erosion in Europe

Small, shallow lakes have the highest P concentrations. No consensus about ‘reference conditions’ accounted

for in the Water Framework Directive has been reached. However, in 75% of the lakes P concentrations are

more than twice as high as ‘comparable concentrations’ based on background values as a basis for forming an

environmental judgement (SEPA, 1999). The value is based on the relationship between absorbance (A420 nm)

of the water and the total phosphorus concentration in many surface waters. It was concluded that considerable

efforts are needed to reduce the P levels caused by anthropogenic activities. The average lake is shallow

(<2.5 m deep) and has a low Secchi disk value (1.1 m) in addition to a high P concentration.

Figure 1.2.2 Silt content (%) of Swedish agricultural topsoils. (Reproduced with permission from Eriksson J, Andersson

A, Andersson R. Texture of Agricultural Topsoils in Sweden. Report 4955, Swedish Environmental Protection Agency,

Stockholm, 1999)

Sweden 19

1.2.3 MONITORING AND FIELD MEASUREMENTS OF EROSION

1.2.3.1 Small Catchments

Until 2003 surface water in small agricultural areas was being monitored on a regular basis, but only on the

basis of weekly, or twice monthly, grab sampling. Since 2003 eight areas have been selected as of special

interest and are now sampled flow-proportionally. Long-term average suspended solids (SS) and TOTP

concentrations in runoff from small catchments are presented in Table 1.2.1. The SS concentrations are

determined after filtration through preweighed and prewashed membrane filters by weighing the filter cake.

Unfortunately, different laboratories have been involved in the analysis. Membrane filters (Schleicher &

Schull, Dassel, Germany) with a pore size of 0.2 mm have usually been used but also other types of filters. One

has also to keep in mind that the concentrations in Table 1.2.1 probably represent underestimated averages

since they are based on infrequent sampling. Eight demonstration watersheds, all which include flow-

proportional sampling of suspended solids and other parameters, are currently being used as a tool to

investigate further the quality of small agricultural streams. The highest annual average SS concentration

(183 mg l�1) has been estimated from a stream on the east coast (county of Ostergotland). High concentrations

(96 and 91 mg l�1) were also found in the region of Lake Malaren and surrounding counties.

1.2.3.2 Observed Fields

The objective of the programme ‘observed fields of arable land’ is to monitor the influence of agriculture

cultivation on the quality of surface water and groundwater within selected fields. The fields (4–32 ha) are

included in the farmers’ regular operations and cover various soil types, cropping and tilling regimes. The

fields have measuring devices for sampling of drainage water and registration of discharge. Up to 16

experimental fields have been monitored for suspended solids (since 1986), in addition to nutrients and major

constituents. The SS concentrations are all determined using membrane filters (Schleicher & Schull) with a

pore size of 0.2 mm. The concentrations are based on biweekly samples (Table 1.2.2). Generally SS

concentrations in drainage water are higher than in the small streams.

Both types of waters have low concentrations of organic substances (Tables 1.2.1 and 1.2.2). Slightly higher

concentrations of ‘other phosphorus’ (total phosphorus minus dissolved phosphate phosphorus) were indicated

TABLE 1.2.1 Number of agricultural catchments, specific area (SA) of the soil (texture), discharge, suspended solids

(SS), pH, total organic carbon (TOC), total phosphorus (TOTP) and other phosphorus (total phosphorus minus phosphate

phosphorus after filtration) in small streams in six regions of Sweden, flow weighted and as an average for 1977–99

Discharge SSb TOCb TOTP Other p

Region No. SAa (mm) (mg l�1) pH % (mg l�1) (mg l�1)

Norrland 2 5.9 207 31 5.8 13 0.12 0.05

W Svealand, 6 4.2 294 44 7.2 15 0.11 0.08

NW Gotaland

Counties surrounding 7 5.9 170 41 7.6 10 0.16 0.09

Lake Malaren

South-east coast 6 3.7 139 34 7.9 9 0.19 0.07

Central Gotaland 4 3.1 341 18 7.2 14 0.09 0.06

Southernmost 10 1.5 282 22 7.7 9 0.16 0.10

acalculated from SA¼ (clay fraction 8þ silt fraction 2.2þ sandy fraction 0.3) bulk density.bmeasured during the period 1986–99.

Source: Carlsson et al. (2002).

20 Soil Erosion in Europe

in the region of Lake Malaren and of the southernmost counties. However, low concentrations of SS were

found in the southernmost streams where the soils have a low clay content.

1.2.3.3 Large Streams

In the large streams, SS is monitored on the basis of monthly values. Filter-papers (Whatman) are used for

filtrations. Since these filters do not catch fine clay particles, the results cannot be compared with the results

from monitoring of agricultural land.

1.2.3.4 Plots

Runoff losses of suspended solids connected to different treatments have been measured as overland flow from

plots at a few sites (Table 1.2.3). They represent different time periods and different types of water collectors.

Concentrations of SS were usually 10-fold those in drainage water but the concentrations of phosphorus did

not differ very much. The erosion losses caused by surface runoff from experimental plots with different tilling

TABLE 1.2.2 Number of observation fields, specific area (SA) of the soil (texture), discharge, suspended solids (SS), pH,

total organic carbon (TOC), total phosphorus (TOTP) and other phosphorus (total phosphorus minus phosphate phosphorus

after filtration) in tile-drained water in six regions of Sweden, flow weighted and as a long-term average 1977–99

Discharge SSb TOCb TOTP Other P

Region No. SAa (mm) (mg l�1) pH % (mg l�1) (mg l�1)

Norrland 2 3.6 275 12 6.2 5 0.05 0.03

W Svealand, NW Gotaland 2 3.0 216 60 6.2 – 0.15 0.07

Counties surrounding 2 9.2 145 230 7.1 13 0.29 0.19

Lake Malaren

South-east coast 4 4.7 145 59 7.6 6 0.12 0.05

Central Gotaland 2 3.6 230 29 7.1 8 0.10 0.06

Southernmost 4 2.7 304 58 7.3 12 0.20 0.08

acalculated from SA¼ (clay fraction 8þ silt fraction 2.2þ sandy fraction 0.3) bulk density.bmeasured during the period 1986–99.

Source: Johansson and Ulen (2002).

TABLE 1.2.3 Number of observation fields, specific area (SA) of the soil (texture), discharge, average and maximum

concentrations of suspended solids (SS), total phosphorus (TOTP) and other phosphorus (total phosphorus minus

phosphate phosphorus after filtration) in surface runoff from plots in different regions. All figures are flow-weighted

averages but periods and number of years differ between sites

Average Max.

Discharge SS TOTP Other P SS TOTP Other P

Region No. SAa (mm) (mg l�1) (mg l�1) (mg l�1) (mg l�1) (mg l�1) (mg l�1)

Norrlandnorth 1 4.0 195 27 0.29 0.10 52 3.26 0.59

Norrland south-west 1 4.2 78 842 0.50 0.45 1700 5.94 5.40

Lake Malaren 1 4.9 62 350 0.49 0.22 670 1.10 0.68

Southernmost 1 4.8 6 544 0.27 0.23 805 0.89 0.62

acalculated from SA¼ (clay fraction 8þ silty fraction 2.2þ sandy fraction 0.3) bulk density.

Source: Johansson and Ulen (2002); Ulen (2003); Ulen and Kalisky (2003).

Sweden 21

and cropping treatments have been monitored from a silty soil with 10% slope for 7 years (Table 1.2.4). The

erosion differed greatly from year to year. Generally, erosion was lower when the soil was tilled during spring and

not tilled during autumn. Direct drilling resulted in other problems (low yield and enhanced losses of dissolved

phosphate). Increased organic concentration in the soil improved the soil structure (Ulen and Kalisky, 2003).

1.2.4 RELATIVE EXTENT OF EROSION IN SWEDEN

The situation in Sweden is that most of the clay soils are drained: 41% of all arable land is systematically

drained (mostly tile-drained), 44% has permeable soils with good natural drainage and 15% may require

improved drainage. The recommended depth for lateral drains is 1.0 m and the recommended drain spacing

ranges from 10 to 30 m depending on hydraulic conductivity and drainage demands. Based on this, a very

rough assumption indicates that a maximum of 15% of arable land is a source of surface erosion via overland

flow either directly to surface waters or indirectly via surface water inlets. Such inlets are primarily installed in

depressions to avoid standing water and convey the water to the subsurface drainage system.

The transport of eroded material to the watercourse is extremely difficult to estimate. In an investigation in

Scania county, between 20 and 80% of eroded material from a field was estimated to leave the field. In another

study, net transport out of a catchment was only 5–10% of eroded material (Mattsson et al., 1989). A large

amount of eroded material may settle on flood plain areas close to the field (Brandt, 1982).

No trend in sediment transport was found in a special investigation from 15 representative Swedish streams

between 1967 and 1994 (Brandt, 1996). It is very difficult to separate the net loss from fields and erosion from

the bottom and the sides of the watercourse. In addition, the location of a field relative to the stream may be

very important (Brandt, 1982).

Field measurements of water soil erosion are very few and of wind erosion even fewer. Alstrom and

Bergman (1986) made an inventory of 29 selected fields with water erosion problems in Scania county. Various

amounts of eroded material, between 0.5 and 300 t ha�1, were lost from the fields. In contrast, mapping of

TABLE 1.2.4 Average (Ave) and standard deviation (SD) of transport (kg ha�1 yr�1) of

suspended solids (SS) and particulate phosphorus (PP) during 7 years from 22 m long plots with

silty soils in the county of Dalarna

SS SS PP PP

Treatment (Ave) (SD) (Ave) (SD)

Conventional autumn ploughing 644 1070 0.32 0.36

Conventional spring ploughing 223 275 0.15 0.15

No-till, except disk harrowing, 365 470 0.28 0.35

autumn

Direct drilling, spring 108 98 0.14 0.10

Deep cultivation 3 times 398 576 0.24 0.23

each autumn

Conventional spring ploughing 273 361 0.15 0.17

and catch crops

Ley/winter wheat and autumn 358 621 0.19 0.23

tilling (wintergreena soil)

Extra organic material added 293 438 0.24 0.25

to the soil (cut grass)

aSoil is not ploughed during autumn.

Source: Ulen and Kalisky (2003).

22 Soil Erosion in Europe

critical areas for erosion in south Sweden was tried using Geographic Information System (GIS) software, a

slope estimator (Van Remortel et al., 2001) and a national digital elevation model (Andersson, 1996). The

results indicated that erosion occurred only in very limited areas in the south.

In a separate study (Alstrom and Bergman, 1992), it was found that only 5% of the fields in Scania suffered

from rill erosion but locally transport by rill erosion may be much higher than sheet erosion. In south and

central Sweden, gullies were inventoried when new national reserve parks were established (Bergqvist, 1990).

However, this serious form of erosion is unusual for arable land in Sweden.

High relative erosion risk areas, calculated using the USLE equation and using large-scale topographic data,

indicate the erosion risk areas to be situated in the east and west part of the country (Figure 1.2.3). If most P

losses are linked to erosion, these parts would also account for most TOTP losses from land. However, at the field

scale no simple and direct relationship between TOTP concentration and average slope was found from the

observed fields. In contrast, soil texture was related to the loss of TOTP (Ulen et al., 2001). Most fields with soils

>35% clay are associated with high SS concentrations (Table 1.2.1). The relationship between topography and

SS concentrations is complicated and a field should be divided into different sections in order to study the erosion

process and for calculation of the length of the erosion path (Djodjic and Bergstrom, 2005).

1.2.5 LEGISLATION AND SUBSIDIES

Legislative concern about erosion does not exist, but there is concern about phosphorus and nitrogen losses

(Table 1.2.5). Locally subsidies have been given for tilling in spring and not in autumn but these have had

limited success (Ulen and Kalisky, 2003).

TABLE 1.2.5 Introduction of legislation related to phosphorus losses in Swedish agriculture in recent years; ‘sensitive’

areas are pollution-sensitive areas in the south together with the coastal area up to central Sweden

Year Part of Sweden Legislation

1994 Southern half 50 or 60% of the arable land shall be ‘wintergreen’ (not autumn-ploughed

soils, winter crops, leys, sugar beets, etc.)

1995 All Livestock density based on phosphorus content in manure is regulated.

Maximum addition of 22 kg P ha�1 is allowed, which is equivalent to

1.6 dairy cows or 10.5 fattening pigs

1995 Sensitive Manure shall not be applied between 1 August and 30 November,

with the exception of application before sowing of winter crops or leys

1996 Southern Manure and other organic fertilizers shall be incorporated within 4 h of

application

1996 Sensitive In pollution-sensitive areas slurry and urine must be incorporated within

4 h of application when spreading on bare soils

1998 All Slurry must be spread to growing crops with techniques that efficiently

reduce NH3 emissions

1999 All Fertilizers must not be applied on water-saturated or flooded ground or on

snow-covered or deeply frozen ground

1999 Sensitive Manure application is not permitted between 1 January and 15 February

1999 Sensitive Application of farmyard manure, with the exception of poultry manure, is

allowed on bare soils, without the requirements of autumn sowing

afterwards: 20 October–30 November in the counties of Blekinge, Scania

and Halland, and 10 October–30 November in the coastal areas of the

counties of Stockholm Sodermanland, Ostergotland, Kalmar, Vastra

Gotaland and Gotland, if incorporation takes place on the same day

Sweden 23

Figure 1.2.3 Relative erosion risk as a median value for municipalities weighed by the total amount of agricultural land

within the municipalities (From Leek R, Rekolainen S, Tema Nord 1996: 615, reproduced by permission of the Nordic

Council of Ministers)

24 Soil Erosion in Europe

1.2.6 SUMMARY

There have been very few studies of erosion in Sweden. Locally the problem is considerable on arable land but

no group has yet done any general quantifications. Problematic agricultural areas are the heavy clay soil areas

around and south of Lake Malaren. In addition, erosion of silty soils along the coast of the northern region and

the west coast might cause problems.

REFERENCES

Alstrom K, Bergman A. 1986. Skador genom vattenerosion i Skansk akermark – ett vaxande problem? Svensk Geografisk

Arsbok 62: 92.

Alstrom K, Bergman, A. 1992. Contemporary soil erosion rates on arable land in southern Sweden. Geogr. Ann. 74A: 101–108.

Andersson L. 1996. Mapping critical areas for erosion and nitrate leaching in southern Sweden. In Regionalisation of Erosion

and Nitrate Losses from Agricultural Land in Nordic Countries, Leek R, Rekolainen S (eds). TemaNord 1996:615. Nordic

Council of Ministers, Copenhagen; 55–59.

Bergqvist, E. 1990. Nip-och Ravinlandskap. Processer och Former, Oversikt och Forslag till Naturreservat. Swedish

Environmental Protection Agency Report 3777. SEPA, Stockholm.

Brandt, M. 1982. Sedimenttransport i Svenska Vattendrag. Sammanstallning och Generalisering av Data Fran Sediment-

transportnatet. Swedish Hydrological and Meteorological Institute RHO Report 33. Liber Grafiska, Stockholm.

Brandt, M. 1996. Sedimenttransport i Svenska Vattendrag, Exempel fran 1967–1994, Swedish Hydrological and Meteor-

ological Institute Hydrological Report 69. SMHI, Norrkoping.

Carlsson C, Kyllmar K, Ulen B, Johnsson H. 2002. Nutrient losses from arable land in 2000/2001. Results from the water

quality monitoring programme. Bulletin, Division of Water Quality Management, No. 66. Swedish University of

Agricultural Sciences, Uppsala.

Djodjic F, Bergstrom L. 2005. Phosphorus losses from arable fields in Sweden – effects of field-specific factors and long-term

trends. Environmental Monitoring Assessement 102: 103–117.

Eriksson J, Andersson A, Andersson R. 1999. Texture of Agricultural Topsoils in Sweden. Swedish Environmental Protection

Agency Report 4955. SEPA, Stockholm.

Johansson G, Ulen B. 2002. Report from the Observed Fields on Arable Land for the Period 1996/99. Division of Soil

Management, Technical Report 28. Swedish University of Agricultural Sciences, Uppsala.

Johansson H, Persson G. 2001. Swedish Lakes with High Phosphorus Concentrations – 790 Natural Eutrophic or

Eutrophicated Lakes; Bulletin 2001:8. Institute of Environmental Assessment, Swedish University of Agricultural

Sciences, Uppsala.

Leek R, Rekolainen S. 1996. Erosion and nitrate leaching risks in the Nordic countries. In Regionalisation of Erosion and

Nitrate Losses from Agricultural Land in Nordic Countries, Leek R, Rekolainen S (eds). TemaNord 1996:615. Nordic

Council of Ministers, Copenhagen 34–41.

Mattsson JO, Rapp A, Sundborg A. 1989. Globala kretslopp – exempel pa floden i det klimatiska systemet. In Svensk

Geografisk Arsbok, No. 65. BTJ, Lund; 21–62.

SEPA. 1999. Swedish Environment Protection Agency (Naturvardsverket). Bedomningsgrunder for Miljokvalitet. Sjoar och

Vattendrag. Report 4913. SEPA, Stockholm.

Steineck S, Jakobsson C, Akerhielm H, Carsson G. 2001. Sweden. In Nutrient Management Legislation in European

Countries, DeClerq P, Gertsis H, Hofman C, Jarvis G, Neetson SC, Sinabell JJ (eds). Wageningen Press, Wageningen.

Ulen B. 2003. Concentration and transport of different forms of phosphorus during snowmelt runoff from an illite clay soil.

Hydrological Processes 17: 747–758.

Ulen B, Kalisky T. 2005. Water erosion and phosphorus problem in an agricultural catchment–need for natural research for

implementation of the EU Water Framework Directive Environmental Science and Policy 8: 477–484.

Ulen B, Johansson G. and Kyllmar K. 2001. Model prediction and a long-term trend of phosphorus transport from arable land

in Sweden. Agrcultural Water Management 4: 197–210.

Van Remortel R, Hamilton M, Hickey R. 2001. Estimating the LS factor for RUSLE the slope length processing of DEM

elevation data. Cartography 30: 27–35.

Sweden 25