relationships between danish organic farming and landscape composition

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Agriculture, Ecosystems and Environment 120 (2007) 330–344

Relationships between Danish organic farming and

landscape composition

Gregor Levin *

Department of Environmental, Social and Spatial Change (ENSPAC), Roskilde University, Universitetsvej 1,

P.O. Box 260, 4000 Roskilde, Denmark

Received 6 March 2006; received in revised form 7 September 2006; accepted 13 October 2006

Available online 30 November 2006

Abstract

This article presents an investigation of relationships between organic farming and landscape composition in Denmark. Landscape

composition was analysed in terms of density of uncultivated landscape elements (I), number of land uses per hectare (II), diversity of land use

(III) and mean field size (IV). Two analytical approaches were used. The first was based on an examination of the national agricultural

registers for 1998, 2001 and 2004. The second approach used aerial photo interpretation for an analysis of 72 conventional and 40 organic

farms within three sample areas for 1982, 1995 and 2002. The national analysis indicated that organic farming has a direct effect on landscape

composition. In 2001, organic farms were characterised by a higher number of land uses per ha, a higher land use diversity and smaller mean

field sizes. From 1998 to 2004, conversion to organic farming was related to an increasing number of land uses per ha, increasing land-use

diversity and decreasing mean field sizes. Relationships between organic farming and landscape composition were independent of variations

in regional location, farm size or farm size change. At the level of sample areas, a significant relationship between organic farming and

landscape composition was only found for densities of small biotopes. However, when differences in farm size and physical geographical

conditions between conventional and organic farms were taken into account, several significant differences in landscape composition were

clarified in two of the three sample areas. Furthermore, changes in landscape composition following conversion to organic farming were

largely biased by the characteristics of the sample areas. Thus, in contrast to the national level, the sample area study indicated that differences

in landscape composition between organic and conventional farms were not a direct implication of organic farming practices, but were related

to variations within other parameters and to the location of organically farmed land.

# 2006 Elsevier B.V. All rights reserved.

Keywords: Organic farming; Conventional farming; Landscape composition; Landscape change; Farm properties

1. Introduction

Organic farming constitutes an important component of

European agriculture, not least in Denmark, where in 2004

over 6% of all arable land was farmed organically (Ministry

of Food, Agriculture and Fisheries, 2004). It is generally

expected that changes in agricultural practices related to

conversion from conventional to organic farming influence

landscape composition. In Denmark, organic farming has

been claimed to be an instrument for the protection and

* Tel.: +45 46742000; fax: +45 46743000.

E-mail address: [email protected].

0167-8809/$ – see front matter # 2006 Elsevier B.V. All rights reserved.

doi:10.1016/j.agee.2006.10.018

improvement of natural and semi-natural elements (FØJO,

2000; Strukturdirektoratet, 1999; Wilhjelmudvalget, 2001).

As far as the EU is concerned, it has recently been suggested

that the proportion of land under organic farming is a

response indicator for the relationship between agriculture

and the landscape (European Environmental Agency, 2005).

Yet, though the principles of organic farming include

sustainable landscape management (IFOAM, 2002), in most

countries, standards and rules for organic farming do not

specifically concern landscape. While it is well documented

that the ban on chemicals in organic farming has a beneficial

effect on flora and fauna within the area of cultivated land

and in edge biotopes (Aude et al., 2003; Benton et al., 2003;

mailto:[email protected]

http://dx.doi.org/10.1016/j.agee.2006.10.018

G. Levin / Agriculture, Ecosystems and Environment 120 (2007) 330–344 331

Stolze et al., 2000; Tybirk et al., 2003), knowledge of the

relationship between organic farming and landscape

composition is limited.

There are two reasons why a relationship between

organic farming and landscape composition can be

expected. First, due to the ban on chemical fertilisers,

organic farming is forced to maintain nutrient balances

through crop rotation with a larger number of crops. This is

expected to lead to a greater diversity in land use and

consequently to more but smaller fields with longer field

margins, which are potential habitats and corridors for wild

flora and fauna (Frederiksen, 2001; van Elsen, 2000).

Secondly, land-use practices and their effects on land-

scape composition have to be seen within a broader

framework, embracing socio-economic and cultural para-

meters, as well as physical geographical conditions (Brandt

et al., 1999; Busck, 2002; Ellis et al., 1999; Kristensen et al.,

2001; Madsen, 2001; Primdahl, 1999; Schmitzberger et al.,

2005). If differences in these conditions exist between

organic and conventional farms, they may imply differences

in landscape composition.

Mander et al. (1999) and Stolze et al. (2000) argue that

existing research indicates that organic farming has a

generally positive effect on landscape composition. How-

ever, when evaluated in the context of applied data and

methods, existing research does not, in fact, support this

proposition. As part of an EU Concerted Action (van

Mansvelt and van der Lubbe, 1999), significant relationships

between organic farming and densities of natural and semi-

natural landscape elements were found in several European

regions (Clemetsen and van Laar, 2000; Hendriks et al.,

2000; Kuiper, 2000; MacNaeidhe and Culleton, 2000; Rossi

and Nota, 2000; Stobbelaar et al., 2000; van Mansvelt et al.,

1998). However, since these investigations were charac-

terised by very small samples (2–8 farms per region), the

results cannot be generalized. Furthermore, the effects of

other farm-specific parameters on landscape composition

were not explored. Investigations using larger samples and

exploring the effects of other parameters indicated little or

no impact of organic farming on landscape composition

(Ackermann, 2003; ENTEC, 1995; Lindkqvist, 2002; Tress,

1999). Generally, production type, farm size and physical

geographical conditions had a much stronger influence on

landscape composition than organic farming. Only two

investigations explored changes in landscape composition:

neither found a significant effect of organic farming

(Ackermann, 2003; Tress, 1999).

On the basis of a lack of appropriate investigations and

the need to document the effects of organic farming, the

main aim of this study was to investigate differences in

landscape composition between organic and conventional

farms. Landscape composition was analysed in terms of the

densities of different uncultivated landscape elements (I),

numbers of land uses per hectare (II), land-use diversity (III)

and mean field size (IV). Two central questions were raised.

First, do differences in landscape composition between

organic and conventional farms exist? Secondly, was

conversion to organic farming followed by changes in

landscape composition? Furthermore, the influence of

regional location, farm size and physical geographical

conditions, as well as interactions between these and organic

or conventional farming, were investigated.

2. Methods

For this paper, two methodological approaches were

adopted. In the first method, data for farm and landscape

parameters for the whole country except the island of

Bornholm were used. In the second method, three sample

areas, covering 40 organic and 72 conventional farms, were

investigated. Table 1 summarizes the parameters applied in

the two analyses.

2.1. Data collection for the national level

For the national investigation, information on organic or

conventional production, year of conversion, farm size, mean

field size, number of land uses per hectare and diversity of

land use was compiled for each farm unit in Denmark on the

basis of the national agricultural registers for 1998, 2001 and

2004 (Ministry of Food, Agriculture and Fisheries, 1998,

2001, 2004). Land uses were classified into categories,

which represent different types and stages of vegetation and

thus deliver different functions for farmland species

(Table 1). Diversity of land use was derived using Shannon’s

index for diversity per ha. The index was calculated as

follows: Sh ¼Pn

i¼1ðPi � ln PiÞ; where Pi is the proportion

of land occupied by land use i. Shannon equals 0 if only one

land use occupies the whole farm unit and increases with an

increasing number of land uses and with an increasingly

equal distribution of land uses. Relations to landscape

composition in 2001 were tested for 3339 organic and

46,264 conventional farms, covering all registered farms in

Denmark except for the island of Bornholm. Due to

biophysical conditions, which are very different from those

on Denmark in general, it was decided to exclude Bornholm

from this study. Furthermore, for the period from 1998 to

2004, changes in numbers of land uses per ha, land-use

diversity and mean field size were calculated for 38,506

farms that could be traced in both registers. In order to test

relationships between time of conversion to organic farming

and landscape changes, the farms were grouped into the

following categories: organic farms that converted before

1998 (N = 825) (I); organic farms that converted between

1998 and 2003 (N = 1248) (II); farms that, in 2004, were

being managed conventionally (N = 36,433) (III). For the

group of farms that converted from 1998 to 2003, the 1998

agricultural register represents the situation prior to

conversion, while the 2004 register represents the situation

subsequent to conversion to organic farming. Farms that

reverted back from organic to conventional were classified as

G. Levin / Agriculture, Ecosystems and Environment 120 (2007) 330–344332

Table 1

Parameters applied for analyses at national and at sample area levels

Description Source Reference

National analysis

Landscape parameters (dependent variables)

Number of land uses per ha Number of land usesa per hectare per farm Agricultural registers Ministry of Food,

Agriculture and

Fisheries (1998,

2001, 2004)

Land-use diversity Shannon diversity for land uses per hectare

per farm

Agricultural registers

Mean field size (ha) Mean area of all cultivated field plots per farm Agricultural registers

Farm parameters (independent variables)

Organic/conventional farming Organic or conventional farming in 2001 Agricultural registers Ministry of Food,

Agriculture and

Fisheries (1998,

2001, 2004)

Time of conversion to organic farming Conversion before 1998; from 1998 to 2003;

conventional


Farm size (ha) Land managed by one farm unit and reported in

agricultural registers in 2001


Change in farm size 1998–2004 Reduced (<�10%); unchanged (�10% to +10%);

increased (>10%)


Region East Denmark and West Denmark Agricultural registers

Sample area analysis

Landscape parameters (dependent variables)

Density of small biotopes (area % of farm) Uncultivated patch elements <2 ha Aerial photos Cowi (1995, 2002)

and National Survey

and Cadastre (1982)

Density of hedgerows (area % of farm) Line elements covered by scrubs or trees Aerial photos

Density of field divides (area % of farm) Line elements covered by grass or herbs Aerial photos

Mean field size (area % of farm) Mean area of all cultivated field plots per farm Aerial photos

Farm parameters (independent variables)

Organic/conventional farming Organic or conventional farming in 2001 Agricultural registers Ministry of Food,

Agriculture and

Fisheries (2001)

Time of conversion to organic farming Conversion before 1995; from 1995 to 2001;

conventional


Farm size (ha) Total area managed by one farm unit Property map, field maps,

aerial photos

COWI (2002),

Danish Plant

Directory (2002)

and National Survey

and Cadastre (2001)

Percentage peat soil (area % of farm) National soil map DIAS (1998)

Percentage slopes > 58 (area % of farm) Digital terrain model National Survey and

Cadastre (2004)

Production typeb Cattle; pig/chicken; mixed/stockless Agricultural registers Ministry of Food,

Agriculture and

Fisheries (2001)

Case area Herning; Randers, Slangerup

a Applied land uses are: spring cereals, autumn cereals, other spring crops, other autumn crops, whole crops, row crops, leguminous plants, fallow, grass in

rotation and grass outside rotation.b Production types were calculated on basis of the economic significance of the respective agricultural products. Cattle, >2/3 of agricultural income from

dairy/meat cattle production; pig/chicken,>2/3 from pig/chicken/egg production; mixed/stockless, <2/3 form either dairy/meat cattle production or from pig/

chicken/egg production.

conventional. All farms were grouped according to their

location in either East Denmark (Zealand and the islands) or

West Denmark (Jutland), and further into those that

decreased in size (>�10%) between 1998 and 2004, those

that did not change in size (�10% to +10%) and those that

increased in size (>10%).

2.2. Data collection for the sample area level

2.2.1. Selection of sample areas and farm units

In addition to national data, relationships between

organic farming and landscape composition were investi-

gated for three sample areas: two in Jutland (Herning and


Fig. 1. Location of the sample areas.

Randers), and one on Zealand (Slangerup) (Fig. 1). The

sample areas, which are described in Table 2, were selected

in order to have a high density of organic farms and to

represent different agricultural landscapes in terms of

physical geographical conditions and agricultural produc-

tion, as well as distance from major urban centers.

The three sample areas include 40 organic and 72

conventional farms. Each farm unit was registered and

demarcated using both maps of agricultural fields (Danish

Plant Directory, 2002) and cadastral maps (National Survey

and Cadastre, 2001). The demarcated farm areas cover all

owned land plus rented land minus land rented out.

Information on production type and organic versus

conventional farming was derived from the national

agricultural register for 2001 (Ministry of Food, Agriculture

and Fisheries, 2001). By means of a spatial overlay with

maps of slope (National Survey and Cadastre, 2004) and soil

properties (DIAS, 1998), percentage of peat soil and

percentage of slopes exceeding 58 was calculated for each

farm unit. All parameters and data sources are summarised

in Table 1.

2.2.2. Land cover registration

A land cover registration was carried out on the basis of a

visual interpretation of aerial photos from 1954 (National

Survey and Cadastre, 1954), 1982 (National Survey and

Cadastre, 1982) and 2002 (COWI, 2002). The registration

embraces 18 land cover classes. All landscape elements

exceeding 20 m2 were registered. The limit of 20 m2 was

chosen on the basis of the resolution of the aerial photos

(0.8 m).

The landscape elements that were used to illustrate

landscape composition at sample area level were defined as

follows.


Table 2

Characteristics of the study areas

Herning Randers Slangerup

Size (km2) 42.3 41.7 31.9

Number of organic farms 12 12 16

Number of conventional farms 24 23 25

Organically managed land (% of area) 18 17 10

Land converted before 1995

(% of organically managed land)

90 92 77

Mean farm size (ha) 50.1 47.2 30.5

Dominant farm types Large full-time farms focusing on

dairy production and pig breeding.

Few part time and hobby farms

Large full-time farms focusing

on dairy and grain production.

Few part time and hobby farms

Small part-time and hobby

farms with mixed production.

Few large farms producing

grain, fruits and vegetables

Geomorphology Outwash plain from last glaciation River valley formed under last

glaciation

Ground moraine and kettle

holes formed under last glaciation

Soil conditions Predominantly sandy soils with few

peat soils along water courses

Peat soils in valley bottom, sandy

soils on valley sides and clay soils

on upland areas

Mosaic of sandy, peat and clay soils

Slope >58 (% of area) 1.1 14.5 9.2

Small biotopes (% of area) 4.3 5.2 6.7

Hedgerows (% of area) 2.7 0.8 0.5

Field divides (% of area) 0.4 0.4 0.7

Mean field size (ha) 3.7 3.3 3.0

Data collection is described in Section 2.2.

Small biotopes are areas of uncultivated natural or semi-

natural land cover with an upper size limit of 2 ha. The size

definition for small biotopes corresponds to Agger et al.

(1986), who developed the term in the early 1980s. The

argument for a size limit of two hectares is that small

landscape elements are often patches located within cultivated

farmland and thus are more exposed to the effects of

agricultural practices than larger landscape elements. Small

biotopes comprise small ponds and lakes and small patches

covered with uncultivated grass, trees, shrubs and/or herbs.

Hedgerows are line elements covered with tree and/or

shrub vegetation. Line elements are defined as elements with

a length of at least 20 m, a width of 1–10 m and a length–

width ratio of at least 5:1. The minimum width was chosen

because the resolution of aerial photos hinders the

registration of widths under 1 m. The width of hedgerows

was measured as crown cover.

Field divides are line elements covered by grass and/or

herb vegetation but no trees or shrubs.

Table 3

Relationships between landscape composition and farm-specific parameters in D

Number of land uses per ha Land-

P Mean Direction P

Organic/conventional ** **

Organic 0.20

Conventional 0.15

Region ** **

East Denmark 0.18

West Denmark 0.13

Farm size (lg.) ** �0.12 **

ns, P > 0.05. *P < 0.05.** P < 0.001.

Field size is the area of an individual plot of cultivated

land. Plots of cultivated land were demarcated by transitions

to other landscape elements or to adjacent plots of cultivated

land with different crops or clearly different patterns of

cultivation.

By means of a spatial overlay between the demarcation of

farm units for 2001 and the land cover registration for 2002,

densities of landscape elements and mean field size were

calculated for each farm unit.

2.2.3. Investigation of changes in landscape

composition

Changes in landscape composition were investigated by

means of an overlay between the land cover maps for 1982,

1995 and 2002. As information on the location of farm units in

1982 and 1995 was not available, the analysis of landscape

changes in relation to conversion to organic farming was not

elaborated at farm level. However, for all organically farmed

fields, the agricultural register for 2001 (Ministry of Food,

enmark (excl. Bornholm) in 2001

use diversity (Shannon per ha) Mean field size (ha)

Mean Direction P Mean Direction

**

0.052 2.83

0.031 3.59

**

0.041 3.12

0.029 3.62

�0.02 ** 0.92


Agriculture and Fisheries, 2001) contains information for the

year of conversion. In combination with the field maps, the

sample areas were divided into land converted to organic

farming before 1995, land converted between 1995 and 2001,

and conventionally managed land. The sample areas were

split up into cells of 100 m � 100 m, and for each cell,

information on the time of conversion to organic farming and

on changes in the densities of landscape elements and in mean

field size was registered. Resolution at 100 m was chosen

because this is fine enough to embrace variations in landscape

composition and the location of fields. A finer resolution

Fig. 2. Landscape composition on organic and conventional farms within

East and West Denmark (excl. Bornholm) in 2001.

would have resulted in a very large number of cells, which

would have been difficult to handle using GIS. For the two

time periods investigated, changes in landscape composition

on land converted to organic farming during the particular

period were compared to changes on other categories of land.

2.3. Data analysis

Relationships between farm properties and landscape

composition were investigated through an analysis of

variance using linear regression (SAS Institute Inc.,

Fig. 3. Landscape composition on organic and conventional farms within

different farm-size categories in Denmark (excl. Bornholm) in 2001.


2004). Dependent and independent variables are listed in

Table 1. To ensure variance homogeneity, logit transforma-

tion was performed for all density data. As relationships

between farm size and density of the investigated landscape

elements and between farm size and mean field size were

characterised by an S-shaped curve, the logarithm of farm

size was used in the analyses. Furthermore, by crossing

explanatory variables, interactions between these variables

and their relationships to landscape composition and

landscape changes were investigated.

Fig. 4. Changes in landscape composition following conversion to organic

farming within East and West Denmark (excl. Bornholm) from 1998 to

2004.

3. Results

3.1. The national level

3.1.1. Relationships between organic farming and


In 2001, organic farms were characterised by signifi-

cantly larger numbers of land uses per hectare, a

significantly higher land-use diversity and significantly

smaller mean field sizes than conventional farms (Table 3).

Fig. 5. Changes in landscape composition following conversion to organic

farming within different categories of change in farm size in Denmark (excl.

Bornholm) from 1998 to 2004.


Landscape composition was also significantly related to

regional location and to farm size. Number of land uses per

hectare and land-use diversity were significantly higher on

farms in East Denmark, while mean field size was

significantly higher on farms in West Denmark. Further-

more, farm size was significantly negatively related to

number of land uses per hectare and to land-use diversity and

positively related to mean field size. Fig. 2 shows that

differences in landscape composition between organic and

conventional farms applied to both East and West Denmark.

Furthermore, Fig. 3 shows that differences in landscape

composition between organic and conventional farms

applied within all groups of farm sizes. Consequently,

Table 4

Changes in landscape composition in relation to farm specific properties in Den

1998

P Mean

Number of land uses per ha

Time of conversion **

Converted before 1998 0.18

Converted 1998–2003 0.15

Conventional 0.15

Region **

East Denmark 0.16

West Denmark 0.15

Change in farm size 1998–2004 **

Decreased (<�10%) 0.10

Unchanged (�10% to +10%) 0.16

Increased (>+10%) 0.12

Land-use diversity (Shannon per ha)



Converted 1998–2003 0.042

Conventional 0.041

Region *

East Denmark 0.045

West Denmark 0.039


Decreased (<�10%) 0.042

Unchanged (�10% to +10%) 0.040

Increased (>+10%) 0.041

Mean field size



Converted 1998–2003 3.61

Conventional 3.91

Region **

East Denmark 3.09

West Denmark 3.51


Decreased (<�10%) 3.02

Unchanged (�10% to +10%) 3.01

Increased (>+10%) 3.15

ns, P > 0.05.* P < 0.05.

** P < 0.001.


conventional farms were independent of variations both in

regional location and in farm size.

3.1.2. Landscape changes following conversion to

organic farming

The period from 1998 to 2004 was generally characterised

by decreasing numbers of land uses per ha, decreasing land-

use diversity and increasing mean field sizes (Table 4).

However, farms that converted between 1998 and 2003 were

characterised by significant increases in number of land uses

per ha, significant increases in land-use diversity and

significant decreases in mean field size. Changes in landscape

mark (excl. Bornholm) from 1998 to 2004

2004 Change 1998–2004

P Mean P Mean

** **

0.17 �0.00

0.17 0.03

0.13 �0.03

** ns

0.14 �0.02

0.13 �0.02

** **

0.16 0.06

0.14 �0.02

0.06 �0.06

** **

0.055 0.002

0.051 0.004

0.034 �0.005

** **

0.039 �0.005

0.027 �0.014

** **

0.046 0.005

0.039 �0.001

0.038 �0.002

** **

3.02 �0.09

3.39 �0.21

4.04 0.13

** ns

3.21 0.11

4.64 0.11

** **

2.63 �0.41

3.22 0.10

3.67 0.53


composition were also related to regional location and change

in farm size. Decreases in number of land uses per hectare and

in land-use diversity and increases in mean field size were

significantly stronger on farms in West Denmark. Farms that

increased in size by more than 10% were characterised by

significant decreases in numbers of land uses per hectare and

in land-use diversity. Farms which increased by size were also

characterised by significant increases in mean field size. Fig. 4

shows that relationships between conversion to organic

farming and changes in landscape composition applied within

both East Denmark and West Denmark. The relationship

between conversion to organic farming and change in

landscape composition was also found for all groups of

change in farm size (Fig. 5). Among farms that decreased in

size and those that did not change in size, farms converted

between 1998 and 2003 were characterised by significant

stronger increases in number of land uses per hectare (Fig. 5a)

and land-use diversity (Fig. 5b) and significantly stronger

decreases in farm sizes (Fig. 5c). Within the group of farms

that increased in size, farms that converted to organic farming

between 1998 and 2003 were characterised by a decreasing

number of land uses per hectare, decreasing land-use diversity

and an increasing mean field size. However, these changes

are less marked than on farms that converted before 1998

Table 5

Relationships between landscape composition and farm specific parameters at sa

Small biotopes (% of farm) Hedgerows (% of f

P Mean Direction P Mean D

Organic conventional

All areas * ns

Organic 14.73 2.13

Conventional 12.67 1.58

Herning ** ns

Organic 7.32 3.01


Randers ns ns

Organic 4.30 0.92


Slangerup ** ns

Organic 6.35 5.51


Production type ns ns

Cattle 12.73 1.82

Mixed/stockless 14.97 1.73

Pig/chicken 8.36 1.86

Case area ns **

Herning 11.56 3.43

Randers 14.01 0.92

Slangerup 14.51 1.05

Farm size (lg.) ** �0.04 ** �Peat soil (% of farm) * 0.20 * �Slope >58 (% of farm) * 0.25 *

ns, P > 0.05.* P < 0.05.

** P < 0.001.

and particularly conventional farms. Consequently, relation-

ships between conversion to organic farming and subsequent

changes in landscape composition between 1998 and

2004 were independent of regional location and change in

farm size.

3.2. The sample area level

3.2.1. Relationships between organic farming and


Table 5 summarises relationships between farm proper-

ties and landscape composition in 2002 for the 40 organic

and 72 conventional farms, which were investigated at

sample area level. For all sample areas together, only density

of small biotopes was significantly related to organic

farming. Within the Herning and Slangerup areas, densities

of small biotopes were significantly higher on organic farms.

Furthermore, in Slangerup mean field size was significantly

smaller on organic farms. Production type was not

significantly related to any of the parameters for landscape

composition. Sample area was only significantly related to

density of hedgerows, with the highest densities occurring in

Herning. Farm size had a significantly negative relationship

to densities of small biotopes, hedgerows and field divides

mple area level in 2002

arm) Field divides (% of farm) Mean field size (ha)

irection P Mean Direction P Mean Direction

ns ns

0.67 2.91

0.54 3.39

ns ns

0.41 3.77

0.38 3.74

ns ns

0.51 3.35

0.49 3.52

ns **

0.74 2.09

0.65 3.64

ns ns

0.50 3.16

0.64 3.23

0.60 3.31

ns ns

0.54 3.30

0.55 3.52

0.66 2.89

0.02 * �0.01 ** 0.97

0.03 ns 0.00 ns �1.88

0.05 ns 0.00 ns �2.37


Table 6

Interrelationships between farm specific parameters at sample area level in

2002

Farm size

(ha)

Peat soil

(% of farm)

Slope >58(% of farm)

P Mean P Mean P Mean

All areas ns ns ns

Organic 42.4 15.2 9.7

Conventional 41.8 13.4 7.5

Herning * ** ns

Organic 51.9 0.12 0.03


Randers * ns ns

Organic 57.9 0.15 0.14


Slangerup ** ns **

Organic 15.6 0.18 0.12


ns, P > 0.05.* P < 0.05.

** P < 0.001.

and a significantly positive relationship to mean field size.

Percentage of peat soil was significantly positively related to

density of small biotopes and significantly negatively related

to density of hedgerows. Percentages of slopes exceeding 58were significantly positively related to densities of small

biotopes.

Relationships between organic and conventional farming

and other farm properties are summarised in Table 6. In

Herning, organic farms were characterised by significantly

greater densities of peat soil. In Slangerup, organic farms

were characterised by significantly smaller farm sizes and

Table 7

Relationships between landscape composition and interactions between

farm parameters at sample area level

Small biotopes

(% of farm)

P Direction

Herning

Organic/conventional �% peat **

Organic �% peat 0.76

Conventional � % peat 0.07

Slangerup

Organic/conventional �% slope >58 **

Organic �% slope >58 0.55

Conventional � % slope >58 �0.07

Mean field size (ha)

P Direction

Slangerup

Organic/conventional � farm size **

Organic � farm size �1.49

Conventional � farm size 1.58

ns, P > 0.05. *P < 0.05.** P < 0.001.

significantly larger percentages of slopes exceeding 58. In

Randers, organic and conventional farms did not differ

significantly.

Testing relationships between landscape composition and

interactions between organic or conventional farms

(Table 7) showed that in Herning the interaction between

organic farming and percentages of peat soil was

significantly positively related to densities of small biotopes.

In Slangerup, the interaction between organic farms and

percentages of slopes exceeding 58 was significantly

positively related to densities of small biotopes. Also in

Slangerup, the interaction between organic farms and farm

size was significantly negatively related to mean field size.

The relationships between organic farms and physical

geographical properties in Herning and Slangerup are

illustrated in Figs. 6 and 7 respectively.

In summary, analyses at sample area level indicated that

in 2002 differences in landscape composition between

organic and conventional farms were significantly influ-

enced by differences in other parameters. Consequently,

organic farming had no direct implications for landscape

composition.

3.2.2. Landscape changes following conversion to

organic farming

Table 8 summarises relationships between conversion to

organic farming and changes in landscape composition.

Between 1982 and 1995, land converted to organic farming

before 1995 was characterised by a significant increase in

densities of small biotopes, hedgerows and field divides and

decreasing mean field sizes. About 80% of all land

converted before 1995 is located in Slangerup. Within

the Slangerup area, no significant difference in change in

landscape composition between land converted before 1995

and other land was found. Consequently, the relationship

between conversion before 1995 and subsequent landscape

changes is biased by this land being located primarily in

Slangerup.

In Herning, land converted to organic farming between

1995 and 2001 was related to a significant decrease in

densities of field divides and a significant increase in mean

field size. Within the other two areas, no relationship was

found between conversion to organic farming between 1995

and 2001 and changes in landscape composition.

4. Discussion

4.1. The effects of organic farming practices on


National data for 2001 showed strong and significant

relationships between organic farming and landscape

composition in terms of larger numbers of land uses per

hectare, higher land-use diversity and smaller mean field

sizes. In general, data for the period from 1998 to 2004 show


Fig. 6. Relationships between organic farming and peat soils in Herning in 2002.

a scale enlargement in agriculture characterised by

decreasing numbers of land uses per hectare, decreasing

land-use diversity and increasing mean field size. However,

in contrast to conventional farms, on farms that converted to

organic farming number of land uses per hectare and land-

use diversity increased, while mean field size decreased.

Relationships between organic farming and landscape

composition in 2001 and relationships between conversion

to organic farming and changes in landscape composition

between 1998 and 2004 were independent of regional

location and of variations in farm size and changes in farm

size.

These results support the assumption that, due to a ban on

chemicals, organic farming is forced to maintain nutrient

balances through crop rotation, resulting in larger numbers

of land uses per hectare, greater land-use diversity and

subsequently more but smaller fields (van Elsen, 2000).

Other studies showed that high land-use diversity benefits

farmland species due to the coexistence of different land

uses or land uses of different kinds and stages of vegetation,

which deliver different functions, like breeding, feeding and

shelter (Krauss et al., 2003; Nagendra, 2002; Norderhaug

et al., 2000; Pino et al., 2000; Weibull et al., 2003). In this

perspective, organic farming benefits the landscape’s ability

to support farmland species.

4.2. The effects of interactions between organic farming

and other farm-specific properties

Results at sample area level only corresponded to a

limited degree with the clear effects of organic farming on

landscape composition that were found at national level. At

sample area level, only density of small biotopes was

significantly related to organic farming. Several significant

relationships were found between landscape composition

and farm size, percentage of peat soil and percentage of

slopes exceeding 58. In Herning and Slangerup, organic

farms differed significantly from conventional farms in

terms of these properties, and these differences implied


conventional farms. In Herning, organic farms were

characterised by high percentages of peat soil, implying

higher densities of small biotopes on organic farms in this

area. Small farm sizes resulted in higher densities of small


Fig. 7. Relationships between organic farming and slopes in Slangerup in 2002.

biotopes, higher densities of field divides and smaller mean

field sizes on organic farms in Slangerup. Furthermore, high

densities of small biotopes were also related to high

percentages of steep slopes on organic farms in Slangerup.

In Randers, where organic and conventional farms were not

significantly different in terms of farm size, percentage of

peat soil or percentage of slopes exceeding 58, no

relationship between organic farming and landscape

composition was found.

Land converted to organic farming before 1995 was

characterised by subsequent increases in densities of small

biotopes, hedgerows and field divides. However, this

relationship is biased by the fact that 80% of all land

converted before 1995 was located in Slangerup. The

explanation for changes in landscape composition in relation

to conversion before 1995 must thus be found within the

characteristics of the Slangerup area. While from 1982 to

1995 Herning and Randers were characterised by decreasing

densities of small biotopes and field divides and increasing

mean field sizes, the opposite changes occurred in

Slangerup. Furthermore, agriculture in Slangerup is domi-

nated by small part-time and hobby farms, including organic

farms in this area. Other studies argue that part-time and

hobby farms are often characterised by the greater

significance of non-productive functions (Frederiksen and

Langer, 2005; Kristensen, 1999; Præstholm, 2002). Conse-

quently, changes in landscape composition following

conversion to organic farming in Slangerup are likely to

be influenced by the dominance of small part-time and

hobby farms in this sample area.

In Herning, land converted between 1995 and 2001 was

related to decreasing densities of field divides and

increasing mean field sizes. Based on an investigation of

landscape changes on organic farms in southern Jutland,

Ackermann (2003) found that, among large dairy farms,

conversion to organic farming was followed by a

rearrangement of field structures resulting in increasing

field sizes. As the effects of conversion to organic farming


Table 8

Changes in landscape composition following conversion to organic farming at sample area level

Small biotopes

(% of farm)

Hedgerows

(% of farm)

Field divides

(% of farm)

Mean field

size (ha)

P Mean P Mean P Mean P Mean

Changes in landscape composition per year, 1982–1995

All ** ** * **

Converted before 1995 0.098 0.026 0.001 �0.07

Other areas 0.012 0.019 �0.002 0.05

Herning ns ns ns ns

Converted before 1995 0.000 0.038 �0.001 0.04

Other areas �0.001 0.037 �0.002 0.05

Randers ns ns ns ns

Converted before 1995 �0.004 0.008 �0.002 0.07

Other areas �0.006 0.008 �0.002 0.06

Slangerup ns ns ns ns

Converted before 1995 0.111 0.028 0.001 �0.08

Other areas 0.100 0.001 0.001 �0.07

Changes in landscape composition per year, 1995–2002

All ns ns ns ns

Converted 1995–2001 0.023 0.011 0.010 0.04

Other areas 0.022 0.012 0.011 0.04

Herning ns ns ** **

Converted 1995–2001 �0.001 0.023 �0.021 0.08

Other areas �0.001 0.020 �0.005 0.02

Randers ns ns ns ns

Converted 1995–2001 �0.018 0.004 �0.008 0.00

Other areas �0.019 0.005 �0.008 0.01

Slangerup ns ns ns ns

Converted 1995–2001 0.101 0.007 0.005 �0.03

Other areas 0.104 0.006 0.004 �0.04

ns, P > 0.05.* P < 0.05.

** P < 0.001.

were investigated at the field level, it was not possible to

link changes in landscape composition to specific types of

production. However, as agriculture in Herning is

dominated by large dairy farms, it is likely that a

rearrangement of field structures following conversion to

organic farming has resulted in increasing field sizes and

decreasing densities of field divides.

Consequently, in contrast to the national analysis, results

at sample area level do not indicate any direct effect of

organic farming on landscape composition. The differences

in landscape composition between organic and conventional

farms were implied by differences in farm sizes and in

physical geographical conditions. Furthermore, differences

in changes in landscape composition following conversion

to organic farming were biased by the specific character-

istics of the sample areas.

4.3. Strengths and limitations of the applied methods

The data and methods used in this study proved to be

convenient tools for the investigation of relationships

between organic farming and landscape composition. The

focus on farm-specific parameters other than organic or

conventional farming enabled the influences and biases of

these parameters to be examined. However, farm parameters

that were not addressed in this study can affect landscape

composition. In particular, parameters related to the farmer

as an actor can influence landscape management. For

example, farmers’ ages, educational backgrounds and

values, as well as differences between full-time, part-time

and hobby farmers, are important for decision-making in

landscape management. Addressing such parameters would,

however, require information from questionnaires or inter-

views, which went beyond the resources available for this

study.

The particular strength of the investigation at the national

level was that results were general for all of Denmark, except

Bornholm. However, as data for landscape composition at

the national level were limited to the number and diversity of

land uses and field size, no general conclusion regarding the

effect of organic farming on densities of uncultivated

landscape elements could be made.


At the sample are level, it was possible to investigate

landscape composition in terms of densities of different

uncultivated landscape elements. However, the sample area

level only applies to 112 farms in the three sample areas.

Although the sample areas were selected to represent different

kinds of Danish agricultural landscapes, the results were not

representative at the national level. This also explains the

limited correspondence between results at the sample area

level and national level respectively. In spite of this limitation,

the sample area analysis identified important concerns for the

effects of organic farming on landscape composition.

5. Conclusions

It is usually expected that organic farming benefits the

composition of agricultural landscapes. Although sustainable

landscape management is embraced in the principles of

organic farming, standards and rules for organic farming do

not concern landscape specifically. On basis of this

discrepancy between principles and rules, and due to a lack

of appropriate investigations, the aim of this study has been to

investigate differences in landscape composition between

organic and conventional farms, as well as to explore changes

in landscape composition following conversion to organic

farming. Two analytical approaches were used. The first was

based on an investigation of national agricultural registers.

The second approach used aerial photo interpretation for an

analysis of three sample areas.

Analyses at the national level identified a clear relation-

ship between organic farming and landscape composition.

Compared to conventional farms, in 2001 organic farms

were characterised by significantly higher numbers of land

uses per ha, greater land-use diversities and smaller mean

field sizes. In contrast to a general scale enlargement in

agriculture, between 1998 and 2004 conversion to organic

farming was significantly related to increasing numbers of

land uses per hectare, increasing land-use diversity and

decreasing mean field sizes. Both landscape composition in

2001 and changes in landscape composition between 1998

and 2004 were related to the regional location of farms and

to variations in farm size and in change in farm size.

However, the effect of organic farming was independent of

variations in these parameters. Consequently, results at the

national level support the assumption that the ban on

chemicals forces organic farms to maintain nutrient balances

through crop rotation, implying increasing numbers of land

uses per hectare and consequently increasing land-use

diversity and decreasing field sizes, thus improving

conditions for farmland species. Although greater land-

use diversities and smaller field sizes are not intended, the

rules for organic farming necessitate land-use practices that

have a direct beneficial effect on landscape composition.

Results at sample area level did not correspond with those

at the national level. For 2002, significant differences

between organic and conventional farms in terms of higher

densities of small biotopes and in terms of smaller mean

field sizes were only found within two of the three sample

areas. Furthermore, differences in landscape composition

were biased by differences in farm size and in physical

geographical conditions between organic and conventional

farms, and were consequently not a direct effect of organic

farming. Changes in landscape composition in relation to

conversion to organic farming were influenced by the

specific characteristics of the sample areas. Analyses

indicated the respective effects of small part-time and

hobby farms, which dominate agriculture in Slangerup, and

of large dairy farms, which dominate agriculture in Herning.

As the sample area analysis only embraced 112 farms, the

results could not be generalized to the national scale.

However, for understanding the relationships between

organic farming and landscape composition, the findings

indicated the necessity to focus on interactions between

organic farming and other farm-specific characteristics.

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