are agricultural land use patterns influenced by farmer imitation?
TRANSCRIPT
Are agricultural land use patterns influenced by farmer imitation?
Claude Schmit *, M.D.A. Rounsevell
Department of Geography, UCL, 3, Place Pasteur, 1348 Louvain-la-Neuve, Belgium
Received 11 April 2005; received in revised form 14 September 2005; accepted 28 December 2005
Available online 23 February 2006
Abstract
This paper proposes a methodology based solely on spatial data to analyse whether and, to what extent, farmer imitation leaves an
observable footprint on an agricultural landscape. Geographical Information System (GIS) analysis of parcel and farm location data of a study
region in central Belgium was developed as an alternative methodology to farmer interviews. Results suggest that imitation is not an important
determinant of agricultural land use patterns in the study area. The effect of imitation on landscapes is limited to the extent of being hardly
significant. Neighbouring parcels cultivated by farmers who live in close proximity are only slightly more similar than neighbouring parcels
cultivated by farmers who live further away from one another. The results question the validity of the assumptions underlying agent-based
models that try to explain agricultural land use through imitation behaviour.
The results should, however, be considered with caution as the proposed methodology has two limitations. First, comparison between
neighbouring parcels could not identify the imitation effect from all factors that influence agricultural land use. Relative space was not
accounted for, which led to two possible explanations for the similarity of neighbouring parcels: imitation or the location of a parcel relative to
the farm. Secondly, the method was applied to aggregated land use classes for a single year, which did not allow for the effect of crop rotations
in understanding imitation behaviour.
# 2006 Elsevier B.V. All rights reserved.
Keywords: Imitation; Agricultural land use; Farmer proximity; Agent-based model; Equi-finality
www.elsevier.com/locate/agee
Agriculture, Ecosystems and Environment 115 (2006) 113–127
1. Introduction
In modelling agricultural land use and land cover
distributions using an optimisation approach, Rounsevell
et al. (2003) generated patterns of land use that were more
spatially-distributed than the reality. They attributed this
observation to the influence of neighbouring land uses on
farmer choices (e.g. White and Engelen, 1993, 1997) that
were thought to create more concentrated land use patterns
in reality. This process can result in actual land use
distributions being significantly different from those, which
might be expected from a knowledge of the physical
conditions (soils and climates) and economic factors alone.
When making decisions about land use and management,
farmers have to cope with large uncertainties related to price
and cost fluctuations, weather variability and policy change.
* Corresponding author. Tel.: +32 10 47 85 06; fax: +32 10 47 28 77.
E-mail address: [email protected] (C. Schmit).
0167-8809/$ – see front matter # 2006 Elsevier B.V. All rights reserved.
doi:10.1016/j.agee.2005.12.019
Their behaviour is typified by multidimensional optimisa-
tion rather than a rational-actor-approach. When faced with
uncertainties, farmers seek robust solutions that often put
into play adaptive social processes (Festinger, 1954;
Lempert, 2002) such as imitation.
Farmers engage in imitation and repetitive behaviour
(habits) to efficiently use their limited cognitive resources
(Jager et al., 2000). Habits describe the repetition of their
originally deliberate choices for as long as the outcomes are
satisfying (Jager et al., 2000). Imitation is an automatic
social process, which relates to the theories of social
learning (Bandura, 1977, 1986) and normative conduct
(Cialdini et al., 1991). Social learning theory states that
watching another person being rewarded for understandable
and reproducible behaviour may result in the imitation of
that behaviour (Jager et al., 2000). Imitation has been
studied as part of the diffusion of innovation process (Ryan
and Gross, 1943; Hagerstrand, 1967). Adaptation of an
innovation depends on the characteristics of the innovation
C. Schmit, M.D.A. Rounsevell / Agriculture, Ecosystems and Environment 115 (2006) 113–127114
itself, the characteristics of the innovators (actors), and the
characteristics of the environmental context (Wejnert,
2002). Examples of farmer imitation behaviour include
the adoption of hybrid corn varieties (Ryan and Gross,
1943), conservation tillage practices (Warriner and Moul,
1992), new fertilizer (Feder and Umali, 1993) or grassland
management practices (Hagerstrand, 1967). Diffusion
processes strongly affect agriculture (Hagerstrand, 1967),
which suggests that private information and local social
networks are especially important in rural areas (Reimer,
1997; Hofferth and Iceland, 1998; Lindsay et al., 2005). The
exchange of information between individuals has been
found to be important for innovation decisions (Berger,
2001) and imitation is known to be a method that land
managers use in choosing between various options (Pomp
and Burger, 1995). Imitation can be understood as a strategy
to economise cognitive efforts, and/or to compensate for an
absence of knowledge (Jager et al., 2000). Imitation
strategies are based on the observation of successful land
uses or techniques (and conversely, avoidance of innovations
that are seen to fail). Farmers rely on information from past
decisions – their own and those of other agents – to update
decision-making strategies (Parker et al., 2002). At the most
critical stages in their decision process, farmers rely on
information brought to them by their peers (Berger, 2001).
Buttel et al. (1990) state that farmers’ decisions were
affected by the opinions and advice of neighbouring farmers.
Lowe et al. (1990) also found that farmers tend to give more
importance to sources of information that derive from the
farming community than elsewhere. The public nature of
farming favours farmer imitation strategies (Newby et al.,
1978). Farming is a very visible activity – visible, to other
local inhabitants, to anyone who passes through the
countryside and more importantly to other farmers.
The existence and observation of a neighbourhood effect
has led to the development of land use and land use change
models that integrate, implicitly, social and behavioural
factors into cellular automata (CA) and agent-based models
(ABM) (Verburg et al., 2004; Engelen et al., 2002; White and
Engelen, 1997; Berger, 2001; Batty et al., 1997; Caruso et al.,
2005). Most CA and ABM are, however, still theoretical. For
example, the Framework for the Evaluation and Assessment
of Regional Land Use Scenarios (FEARLUS) approach used a
simple, but abstract agent-based model to explore in a
spatially explicit way the performance of imitative versus
non-imitative strategies of land use selection by land
managers (Gotts et al., 2003). The model showed that the
success of a range of different imitative strategies depended
on the context in which imitation takes place. Performance
depends on the strategies being followed by other agents and
various aspects of the spatio-temporal heterogeneity of the
environment: the balance between spatial and temporal
variability, the predictability of variations over time, and the
scale of spatial heterogeneity (Polhill et al., 2001).
The incorporation of a micro-level perspective on human
behaviour within integrated models of land use and land
use change would potentially provide a better understanding
and eventual management of the processes involved in the
formation of landscape patterns (Jager et al., 2000).
However, a wide gap remains between the theoretical
implications of agent-based models (ABM) and empirical
data (Parker et al., 2003). It is difficult to parameterise and
validate ABM due to their large data requirements (Verburg
et al., 2001). A model of a complex land use system has
many parameters that change both in space and in time,
which require calibration and validation data at a high spatial
and temporal resolution. The lack of individual data limits
ABM model validation (Parker et al., 2003). Furthermore,
multi-agent models are often built on anecdotal evidence
because of the problem of equi-finality (or multi-causality)
that cannot always be resolved though calibration. The same
final state or condition of a system may be reached from
different initial conditions (inputs) and in different ways
(transformations). It is difficult to find unequivocal
empirical evidence for the very micro-level laws that give
the models their richness (Jager et al., 2000). With different
techniques, an infinite number of models can be created,
whilst reality remains constant. It is possible to develop a
model that can reproduce a statistically correct meta-
phenomenon with a model structure that does not capture
any real processes (Parker et al., 2003).
Taking advantage of the availability of detailed spatial
data, the research presented in this article addresses the
validity of the assumptions about imitation that underpin
many agent-based models of agricultural land use. More
generally, the objective of this paper was to propose a
methodology based solely on spatial data to analyze whether
and, to what extent, farmer imitation leaves an observable
footprint on land use in an agricultural landscape. The goal
was to gain insight into farmer imitation from the
Geographical Information System (GIS) analysis of parcel
and farm location data only. This is proposed as an
alternative (and complimentary) methodology to most
studies of social processes that use interviews or surveys
(Ryan and Gross, 1943; Stockdale, 2002; Chiffoleau, 2005;
Lindsay et al., 2005). The basic principle of the
methodology was to test whether the land use of
neighbouring parcels cultivated by farmers living close to
one another were more similar than neighbouring parcels of
farmers who are separated by greater distances. The
methodology relied on two assumptions. First, the socio-
informational networks of farmers decay with distance
(Ryan and Gross, 1943; Hagerstrand, 1967; Lindsay et al.,
2005). Thus, the distance between farms determines the
frequency of interactions and the quantity of information
exchanged between farmers. If imitation influences agri-
cultural land use patterns, then the distance between farms
cultivating two neighbouring parcels should influence the
similarity of those parcels. The second assumption was that
analysing neighbouring parcels allows the control of all
other factors (such as physical and political factors) that
influence agricultural land use. In comparing neighbouring
C. Schmit, M.D.A. Rounsevell / Agriculture, Ecosystems and Environment 115 (2006) 113–127 115
parcels over distances of a few hundred meters, it is
reasonable to assume that the independent variables of
climate, soils and policy (explaining the dependent variable
‘‘land use’’) are constant.
Fig. 1. Map of the location of the case study area (B, Brussels region).
2. Material and methods
2.1. The case study area
The work presented here is based on a case study region
in central Belgium defined as the Dyle river catchment
(508380N, 48450E) within the Walloon region, a 650 km2
catchment which is part of the Scheldt river basin. The study
region is characterised by a heterogeneous landscape that is
typical of northwest Europe, with a predominance of mixed
agriculture (crop cultivation and livestock production), and
high urbanisation (about 20% of the total land use area)
because of the proximity to Brussels. The study region was
chosen because detailed land use parcel data were available,
as well as additional spatial information.1
2.2. Parcel data
The basic landscape unit considered in this study is the
parcel, which is a contiguous entity of unique agricultural
land use cultivated by a single farmer. The vector land use
data used in this paper were obtained from the Integrated
Administration and Control System (IACS) (EEA, 2001).
The IACS monitor all agricultural parcels of holdings that
receive subsidies within the European Union (EU) area
payment scheme. Data is collected directly from farmers,
who are required to indicate the boundaries of all parcels
they cultivate on aerial photographs and to specify the land
use. These maps are digitised and used to monitor farmer
area declarations. The IACS vector dataset provides
therefore a detailed source of information about subsidised
agricultural land use (EEA, 2001) with high spatial detail
(parcel polygons) and thematic accuracy (more than 40
different crop types, see Appendix A).
The IACS database for the study region included all
parcels of farmers that cultivated at least one parcel within
the boundaries of the Dyle catchment during the year 1999.
Therefore, the extent of the dataset is not limited to the Dyle
catchment, as shown in Fig. 1. The dataset comprised 16,464
parcel polygons, of which 11,186 are located within the Dyle
catchment. The parcels cover an area of 48,660 ha (with
31,311 ha within the catchment). The main crop rotation is
winter wheat and sugar beet, which makes up half of the total
agricultural parcel area (winter wheat 30% and sugar beet
20%). Permanent grassland (16%) is the third most
important agricultural land use in terms of surface and
the second most important in terms of parcel numbers. The
1 Soil maps, climate data, road and river networks, administrative bound-
aries, aerial photography, agricultural census data per commune.
parcels are cultivated by 918 farm holdings, of which the
average farm size is 53 ha. The parcels are located in the
same administrative region, and therefore the same laws and
regulations apply.
2.3. Farm location data
The locations of farm buildings were manually geo-
coded as points. The farm building postal addresses were
collected for every farm holding cultivating at least one
parcel within the boundaries of the Dyle catchment. These
addresses were located on a map using an online route-
planning program (www.mappy.be). In ArcMap 8.3
(Environmental Systems Research Institute, ESRI Inc.),
the exact building locations were identified on aerial
photographs and digitised topographic maps at a scale of
1:10,000. For 67 of the 918 farms, postal addresses were
not available. For each of these farms, the gravity centre
of the farm’s parcels was calculated. The farm building
location was then estimated as the closest building
(recognizable on the 1:10,000 topographic map or on
the aerial photographs) to the gravity centre.
Some farmers operate from several production units
without declaring all of them, whereas others do not
necessarily cultivate their parcels from the location
specified in their mailing address. A field survey was used,
therefore, to validate a subset of the geocoded database.
Furthermore, an effort was made to quantify the uncertainty
or error associated with the location of all of the farm
buildings. A small sub-routine programmed in ArcMap
allowed the display of a particular farm location and its
corresponding parcels. Visual analysis of the mapped
representation of the farm building location relative to the
location of the parcels allowed an expert judgement to be
made about the quality of the geo-referenced farm
locations. A variable named ‘‘LOK’’ was generated for
each farm to quantify the subjective confidence in the
location of the farm buildings, based on criteria such as the
C. Schmit, M.D.A. Rounsevell / Agriculture, Ecosystems and Environment 115 (2006) 113–127116
Table 1
Coding of the accuracy of the geocoded farm building locations
Farm location OK? LOK-value
Perfect, no doubts 5
Good 4
Fair 3
Unusual, but possible 2
Bad, not likely 1
Worse 0
Missing �1
LOK-value, location of farm OK-value.
Fig. 2. Illustration of the buffer 50 m method to determine neighbouring
parcel pairs.
dispersion of the parcels relative to the farm, the distance
from the farm to the closest parcel and on the overall
clustering of the parcels. The ‘‘LOK’’ coding is shown in
Table 1.
The subsequent sections outline how the imitation
hypothesis was tested and describe how ‘‘neighbouring
parcels’’, ‘‘similarity’’ and ‘‘social distance’’ were deter-
mined.
2.4. Neighbouring parcels
Individual parcels were in vector format polygons (ESRI
shapefiles) that represent their actual shape and georefer-
enced position. GIS techniques were used to define the
neighbourhood of each parcel and to link neighbouring
parcel pairs. Two approaches to the estimation of neighbours
were tested: 50 m buffers and Thiessen polygons.
2.4.1. Buffer 50 m neighbourhood (Buf50 m)
A buffer of 50 m was generated around each parcel using
the ARC MAP Buffer Wizard. The newly created polygons
included the parcel and a buffer zone of 50 m around the
parcel. An identifier of the original parcel (‘‘PID’’) was
attributed to each of the ‘‘parcel + Buffer’’ polygons. The
theme of the ‘‘parcel + Buffer’’ was intersected with the
‘‘parcels-only’’ theme. This produced an attribute table with
two parcel IDs in each row, which were the IDs of the parcels
neighbouring each other. In order to map the parcel
neighbours, a line theme was created in ARC CATALOG
to link the centroids of the neighbouring parcels (Fig. 2).
If parcel A is a neighbour of parcel B, then parcel B is also
a neighbour of parcel A. For the analysis of neighbouring
parcels, the direction of the link is of no importance.
Because every pair-wise observation is represented twice
(parcel link A–B and parcel link B–A), the dataset was
filtered for the redundant (B–A parcel link) representations
of neighbouring parcel pairs.
The buffer distance was set to 50 m for two reasons. First,
parcels separated by a road should still be regarded as
neighbours and most roads (except some highways) are less
than 50 m wide. Secondly, wider buffer distances would
generate more neighbouring parcel pairs and a larger dataset
is better for statistical analyses. However, over greater
distances, the physical characteristics of the environment are
no longer constant, which contravenes the basic assumption
made here that neighbouring parcels should have basically
the same physical characteristics.
A drawback of the buffer method is that parcels that are
further apart than the buffer distance are considered to be
completely isolated. These parcels are systematically
excluded from the analysis, which influences the results.
Thus, in order to test the sensitivity of the results to the
choice of method, an alternative way of defining parcel
neighbourhoods, based on the use of Thiessen polygons, was
also applied.
2.4.2. Thiessen polygon neighbourhoods
The parcels were first represented by a point theme that
was created from the coordinates of the centroids of the
parcel polygons. The Thiessen method creates non-over-
lapping polygons around each parcel centre point. Each
Thiessen polygon encloses the area that is the closest to the
enclosed parcel centre: the boundaries of the polygons are
fixed at an equal distance between two parcel centres.
Parcels were defined as neighbours if their respective
Thiessen polygons shared a common edge. The neighbour-
ing parcel pairs were linked with lines (Fig. 3).
The advantage of this method is that every parcel has a
similar number of neighbours and there are no isolated
parcels (compare Fig. 3 to Fig. 2). Conversely, the distance
between parcel neighbours can be highly variable.
2.5. Similarity
The similarity between neighbouring parcels was deter-
mined by agreement of the agricultural land use classes. Each
of the 43 different crops in the parcels dataset forms a
different agricultural land use class. For each neighbouring
parcel pair, a binary variable was created, which took the
value 1 if the land use of parcel Awas the same as the land use
of parcel B, and 0 otherwise. The ratio of similar parcel pairs
C. Schmit, M.D.A. Rounsevell / Agriculture, Ecosystems and Environment 115 (2006) 113–127 117
Fig. 3. Illustration of the Thiessen method to determine neighbouring
parcel pairs (for the same parcels as in Fig. 2).
2 A commune is the basic administrative unit in Belgium and is equivalent
to the NUTS 5 (Nomenclature of Territorial Units or Statistics) level.
Belgium is covered by a total of 589 communes.
over the total number of neighbouring parcel pairs (in
percent) was used as a general measure of similarity. Acreage
percentages were not considered because parcels, rather than
hectare, represent functional landscape units. Decisions
concerning land use are taken per parcel.
2.6. Social distance
If farmers follow imitation strategies they will gather
information from their peers. Due to a lack of spatial data on
social networks and social contacts, the exchange of
information between farmers was approximated, based on
indications from the literature. According to Lindsay et al.
(2005) social networks in rural areas tend to be small, dense
and homogeneous, confirming the findings of Hagerstrand
(1967): on average, the density of contacts included in a
single person’s private information field decreases very
rapidly with increasing distance. Social relationships within
rural communities have retained a distinctive culture and
dynamic (Halfacree, 1994). Despite life-style changes,
social networks provide stability (Letenyei, 2001; Harrison
and Carroll, 2002).
2.6.1. Neighbouring parcels cultivated by the same
farmer and by different farmers
The same farmer often cultivates neighbouring parcel
pairs. In this case the social distance is zero. The dataset of
unique neighbouring parcel pairs was split into two subsets:
parcel pairs cultivated by the same farmer, and parcel pairs
cultivated by different farmers. The frequencies of
neighbouring parcel pairs were summarised in a bivariate
table with the rows reporting whether farmers were the same
or different and the columns reporting whether parcels were
similar or not. A Chi-square (x2) test was carried out to
investigate the existence of a relationship between the two
variables (similarity of farms and similarity of neighbouring
parcels). Rejection of the null hypothesis indicates a
statistically significant relationship between the variables.
A significant relationship could be interpreted as a sign of
auto-imitation (Polhill et al., 2001), but this was not the main
objective of the work presented here. Subsequent analyses
were, therefore, performed on the subset of neighbouring
parcel pairs cultivated by different farmers.
2.6.2. Administrative units
A hierarchical system of administrative units may impose
a certain structure on human societies. In Belgium, the
hierarchical levels include communes,2 arrondissements,
provinces, regions and the nation state. As communes occur
at the lowest level in this hierarchical structure it was
hypothesised that farmers belonging to the same commune
would have more social contact than farmers belonging to
different communes. Social distance between farmers
cultivating neighbouring parcel pairs was, therefore, related
to the administrative units within which the farms were
located. For every neighbouring parcel pair, the farm
building locations of both parcels were joined to the parcel
link attribute table. Farm locations were given a commune
code based on the location of the farm building. The Dyle
catchment study area included 7 complete communes and
parts of a further 24 communes. The neighbouring parcels of
farmers living in the same commune were then compared to
neighbouring parcels of farmers living in different commu-
nes. In this way, the commune level was used to represent the
community where the farmer exchanges information.
Whether a farm pair was located in the same or in a different
administrative unit was coded with a binary variable. As
before, frequencies were summarised in a bivariate table
and a Chi-square test was used to analyse the relationship
between the similarity of neighbouring parcels and the
similarity of the communes of the farms cultivating those
parcels. Parcel pairs cultivated by farms located within the
same commune were expected to be more similar than those
cultivated by farms located within different communes.
2.6.3. Euclidian distance
The use of a binary variable (same or different commune)
masks information about the distance decay in social
networks. Exchange of information between farmers may be
stronger between administrative units that are closer to one
another than between those that are further apart. In order to
characterise the distance decay function in social networks
in greater detail a cardinal variable was calculated, the
Euclidian distance between farm buildings of parcels
located next to one another. The farm buildings of
neighbouring parcel pairs were linked by a line theme.
Then, the distances between farms were classified into
100 m intervals. Absolute and cumulated frequencies of the
neighbouring parcel pairs as a function of the distance
C. Schmit, M.D.A. Rounsevell / Agriculture, Ecosystems and Environment 115 (2006) 113–127118
between farms were represented on a graph. Furthermore,
within each 100 m interval, the ratio of the frequency of
neighbouring parcel pairs to the same land use over the total
number of neighbouring parcel pairs was calculated accord-
ing to Eq. (1) and plotted on another graph representing
the similarity of neighbouring parcel pairs against distance
between farms.
Sið%Þ ¼Nsi100
N�i(1)
where Si(%) is the similarity (in percent) between neigh-
bouring parcel pairs for ‘‘distance between farms’’ interval i,
Nsi the number of neighbouring parcel pairs with the same
land use cultivated by farmers who live within a distance
interval i of one another, N�i is the total number of neigh-
bouring parcel pairs cultivated by farmers who live within a
distance interval i of one another.
The similarity values per 100 m farm distance intervals
were compared to the average similarity between neigh-
bouring parcels for the whole dataset (for all distances
between farms) in order to test whether parcels are more
similar when the farms cultivating them are closer to one
another. A polynomial trend was fitted to the points
representing the similarity versus distance between farms.
First, a second order polynomial was applied to the observed
points based on the equation:
Sið%Þ ¼ aþ b1distþ b2dist2 (2)
with dist expressed in metres. When the b2 coefficient in
Eq. (2) was not significant at the 0.05 threshold, the points
were approximated with a linear regression, characterised by
the following equation:
Sið%Þ ¼ aþ b1dist (3)
The sensitivity of the results to the choice of the method
for defining neighbouring parcels (Buf50 m or Thiessen
method) and to the uncertainty linked to the geocoding of
the farms were both investigated. In order to facilitate
comparison, similarity between neighbouring parcel pairs as
a function of distance between farms was expressed as a
location-specialisation index I1 (Eq. (4)).
I1 ¼Nsi=N�iN�s=N��
(4)
(adapted from Beguin, 1979); where Nsi is the number of
neighbouring parcel pairs with the same land use cultivated
by farmers who live within a distance interval i of one
another, N�i the total number of neighbouring parcel pairs
cultivated by farmers who live within a distance interval i of
one another, Ns� the total number of neighbouring parcel
pairs with the same land use (for all farm locations), and N��is the total number of neighbouring parcel pairs. The I1 index
compares the percentage of similar parcels within a ‘‘dis-
tance between farms’’ interval to the average percentage of
similar parcels in the study area. A value above 1 indicates
that similar parcel pairs are over-represented within a ‘‘dis-
tance between farms’’ interval.
In order to quantify the effect of the uncertainty associated
with the geocoding of farm locations on the similarity
between neighbouring parcels, the dataset of all parcel pairs
(determined with the Buf50 m method) was filtered according
to a threshold value of a new variable named MLOK. MLOK
was defined as the product of the LOK variable (see Table 1)
for both of the farms linked through a neighbouring parcel
pair. Threshold values were fixed at 9 and 15.
2.7. Exclusion of grassland
Previous studies on the same parcel database showed that
the location of grassland has a strong relationship with the
distance between parcels and farms (Schmit et al., 2006).
This may bias the conclusions about the possible influence
of farmer imitation on agricultural land use patterns.
Therefore, a further analysis was undertaken in which all
grassland parcels were excluded from the dataset of the
neighbouring parcel pairs cultivated by different farmers,
determined with the Buf50 m method. The effect of grass-
land exclusion on the similarity of parcel pairs was analysed
with the social distance measured both as the Euclidian
distance between farms and as the similarity of communes.
The use of this approach is further discussed later.
3. Results and discussion
In the following discussion, unless otherwise stated, the
Buf50 m method was used to determine neighbouring parcel
pairs. The results are presented from the most general to the
most detailed level of analysis.
3.1. Neighbouring parcels cultivated by the same
farmer and by different farmers
Thirty-seven thousand five hundred and thirty-six unique
neighbouring parcel pairs were determined (with the
Buf50 m method) from the 16,464 agricultural parcels in
the case study dataset. On average, only 22.18% of these
parcel pairs had the same agricultural land use (Table 2).
Almost a third of all neighbouring parcel pairs (31.68%)
are cultivated by the same farmer, so that two thirds of the
pairs could be used in the analysis. The neighbourhood
statistics of parcels shown in Table 2 also indicates that
neighbouring parcel pairs cultivated by the same farmer
tend to be more similar (26.31% similarity on average) than
neighbouring parcels cultivated by different farmers
(20.26% similarity). The Chi-square (x2) test probability
of 2 � 10�39 led to rejection of the null hypothesis,
meaning that there is a statistically highly significant
relationship between the similarity of neighbouring parcels
and the similarity of farms cultivating those parcels. The
overall similarity of parcels cultivated by the same farmer
C. Schmit, M.D.A. Rounsevell / Agriculture, Ecosystems and Environment 115 (2006) 113–127 119
Table 2
The cross-tablulation matrix of the similarity of unique neighbouring parcel
pairs against the similarity of farms that cultivate neighbouring parcels
Farms Neighbouring parcel pairs land use
Different Same Total
Different 20449 5196 2564554.48 13.84 68.32
79.74 20.26 100.00
70.00 62.41 68.32
Same 8762 3129 1189123.34 8.34 31.68
73.69 26.31 100.00
30.00 37.59 31.68
Total 29211 8325 3753677.82 22.18 100.00
77.82 22.18 100.00
100.00 100.00 100.00
The upper numbers of each entry (in bold) give the absolute frequencies, the
second numbers (in normal font) give the percentages of all observations
(37,536), the third numbers (in italic) give the percentages of the row totals,
the fourth numbers (also in normal font) give the percentages of column
totals.
of 26.31% can be interpreted as a sign of mixed farming
(crops and livestock). On average one farmer cultivates 6
different crops. With specialized farms (farms cultivating a
single crop), the similarity between neighbouring parcel
pairs cultivated by the same farmer would be expected to be
much higher.
3.2. Administrative units
Table 3 shows the results of the comparison of the
neighbouring parcels of farmers living in the same commune
Table 3
The cross-tablulation matrix of the similarity of unique neighbouring parcel
pairs (cultivated by different farms) against the similarity in the communes
where the farms of the neighbouring parcel pairs are located
Communes of farms Neighbouring parcel pairs land use
Different Same Total
Different 7504 1755 925929.26 6.84 36.10
81.05 18.95 100.00
36.70 33.78 36.10
Same 12945 3441 1638650.48 13.42 63.90
79.00 21.00 100.00
63.30 66.22 63.90
Total 20449 5196 2564579.74 20.26 100.00
79.74 20.26 100.00
100.00 100.00 100.00
The upper numbers of each entry (in bold) give the absolute frequencies, the
second numbers (in normal font) give the percentages of all observations
(25,645), the third numbers (in italic) give the percentages of the row totals,
the fourth numbers (also in normal font) give the percentages of column
totals.
to neighbouring parcels of farmers living in different
communes.
Only parcel pairs cultivated by different farmers were
taken into account. As a consequence the frequencies in the
‘‘total’’ row from Table 3 are identical to the frequencies in
the first row of Table 2. Table 3 shows that parcel pairs
cultivated by farms located within the same commune were
slightly more similar (21.00%) than those cultivated by
farms located in different communes (18.95%). This
difference of 2% is highly significant (x2-test probability
of error: 9 � 10�5), meaning that the differences in cell
frequencies in Table 3 cannot be explained by chance. The
similarity of the communes, where farms are located, has an
influence on the similarity of neighbouring parcels.
3.3. Euclidian distance between farms
3.3.1. Similarity of parcels as a function of distance
between farms
The similarity between parcel pairs was investigated as a
function of the distance between farms. First, the ‘‘distance
between farms’’ variable was classified into regular 100 m
intervals. Fig. 4 represents the absolute and accumulated
frequencies of neighbouring parcel pairs as a function of the
distance between farms.
Absolute frequencies decrease with increasing distance
between farms. More than half of all neighbouring parcels
pairs were cultivated by farmers who live less than 2 km
apart. An explanation for this particular frequency distribu-
tion is that the variables ‘‘distance between farms’’ and
‘‘distance from the farm to the parcels’’ are not completely
independent. Farmers prefer to cultivate parcels that are
closer to their farms.
The results presented in the previous sections showed
that differences in similarity between neighbouring parcel
pairs were not very important; they have a range of just a
few percent. The distance intervals were set to 100 m in
order to highlight these slight differences. For the
‘‘distance between farms’’ inferior to 3 km, the frequencies
Fig. 4. Absolute and cumulated frequencies of the distribution of neigh-
bouring parcel pairs as a function of distance between farms.
C. Schmit, M.D.A. Rounsevell / Agriculture, Ecosystems and Environment 115 (2006) 113–127120
Fig. 5. Similarity between neighbouring parcel pairs (%) as a function of
distance between farms (buffer 50 m method with linear regression trend
lines).
of parcel pairs per distance interval had more than 100
observations. Increasing the distance intervals would
create fewer classes with more observations in each
interval, but with a reduced resolution for the ‘‘distance
between farms’’ variable.
The similarity, Si(%) (see Eq. (1)) as a function of
distance between farms is plotted in Fig. 5. The average
similarity between neighbouring parcel pairs is 20.26%.
There seems to be a decreasing linear trend for the
‘‘distance between farms’’ below 1000 m. Above 1000 m
similarity appears to vary around the mean similarity, with
the variability increasing at greater distances. The dataset
was split into two subsets (‘‘distance between farms
inferior’’ to 1000 m, and distance between farms superior
to 1000 m). For both subsets, a second order polynomial
curve, based on Eq. (2) was fitted through the observed
points. For ‘‘distance between farms’’ inferior to 1000 m,
the b2 coefficient was not significant at a 0.05 threshold,
leaving a linear regression (3), characterised by the
following equation:
Sið%Þ ¼ 25:9446� 0:0087dist (5)
and an R2 value of 0.89. This means that the average
similarity of neighbouring parcels is 26% for parcels culti-
vated by farmers who live immediately next to one another.
For every 100 m that farmers live further apart, similarity
between parcels drops by about 0.9%. This is quite a weak
decrease, but one that is statistically highly significant.
These initial results suggest that neighbouring parcels
cultivated by the same farmer are more similar (26.31%
similarity) than those cultivated by different farmers. This
26.31% similarity is close to the value of the a coefficient
(25.95%) of the linear regression (Eq. (5)), which confirms
that neighbouring parcels cultivated by the same farmer are
just a particular case, where ‘‘distance between farms’’ is
zero. This can be interpreted as auto-imitation. It is likely
that farmers repeat their own successful cropping strategies
(Jager et al., 2000) and/or economies of scale explain this
behaviour. Furthermore, fieldwork may be easier if a farmer
cultivates neighbouring parcels in the same way. Space is
used more efficiently and the time and distance spent
moving from the farm to the parcels is reduced (Von Thunen,
1966).
It is also worth noting the link between social proximity of
farmers and the location of their farms in administrative units.
Fig. 5 shows that the similarity of neighbouring parcels is
above average for the ‘‘distance between farms’’ within a
range of 0–700 m, and below average between 700 and
1000 m. There is a small breakpoint at 700 m, which
corresponds, approximately, to the average diameter of
villages within the study area. This suggests that the village is
a better representation of the structure of farming commu-
nities and their social networks than the commune.
Communes were used in the analysis presented here because,
technically, it is more difficult to attribute farms to villages
than to communes, since a village is not an administrative unit
(covering the whole territory) and village boundaries are not
clearly defined. Attributing farm locations to villages would
need to be based on a subjective judgement.
For the ‘‘distance between farms’’ above 1000 m, both b1
and b2 of Eq. (2) were not significant. There is no trend
beyond 1000 m and a horizontal line at the average value of
similarity (equation: Si(%) = 19.49) is used as an approx-
imation of the data points. The trend lines are shown in
Fig. 5. The variability of the similarity increases with
increasing distance between farms, largely due to the
decrease in the number of observations in each 100 m
distance interval (as seen in Fig. 4). A solution to reduce this
variability is to classify the distance between farms
according to quantiles of the frequencies of neighbouring
parcels. With simple visual analysis the decreasing trend in
similarity with increasing distance between farms is hard to
detect due to the scatter of the data points.
Lines between parcel centroids were used to represent on
a map the neighbouring parcel pairs cultivated by different
farmers (Fig. 6). The lines were coloured according to the
similarity of the neighbouring parcels. Visual analysis shows
little apparent pattern or trend in the spatial distribution of
similar parcels. As for the analysis of residues in a
regression, spatial patterns or clusters of neighbouring
parcels can give clues about possible alternative causes of
similarity (other than imitation), or about important
variables that have been omitted from the analysis.
3.3.2. Sensitivity to the method for defining
neighbouring parcels
The results presented in the previous section were obtained
using the Buf50 m method for determining neighbouring
parcel pairs. In order to examine to what extent the choice of
the method has influenced these results, the Thiessen polygon
method was compared to the Buf50 m method. Table 4
provides the basic statistics for both methods.
Whereas the mean number of neighbours is not very
different (4.9 for Buf50 m compared to 6.1 for Thiessen), the
C. Schmit, M.D.A. Rounsevell / Agriculture, Ecosystems and Environment 115 (2006) 113–127 121
Fig. 6. Map of the Dyle catchment study area, with neighbouring parcel pairs cultivated by different farmers represented as lines.
Thiessen method has a lower variance, which can also be
seen in Fig. 7.
With the Buf50 m method, there are 1178 isolated
parcels, i.e. parcels that do not have any neighbours.
Independent of the method, about a third of the neighbouring
parcels is cultivated by the same farmer.
The average similarity of the parcel pairs determined with
the Thiessen method (20.18%) is slightly lower than that
obtained with the Buf50 m method (20.26%). Therefore, in
Table 4
Comparison of the Buffer 50 m method with the Thiessen method to define
neighbouring parcel pairs
Buf50 m Thiessen
Number of parcels having at least 1 neighbour 15286 16464
Number of isolated parcels 1178 0
Mean Number of neighbouring parcels 4.91 6.09
Median Number of neighbouring parcels 5 6
Minimum Number of neighbouring parcels 0 2
Maximum Number of neighbouring parcels 22 14
SD of Number of neighbouring parcels 2.79 1.37
Variance of Number of neighbouring parcels 7.77 1.87
Number of unique parcel pairs 37536 50068
Number of unique pairs from same farm 11891 15723
Number of unique pairs where farms are different 25645 34345
% of unique pairs from same farm 31.68 31.40
% of unique pairs where farms are different 68.32 68.60
order to represent the variations of similarity of neighbour-
ing parcels with distance between farms, the I1 index was
used (see Fig. 8) rather than the percentage similarity (as
used in Fig. 5).
The I1 similarity (Fig. 8) does not affect the distribution
of the points for the Buf50 m method. Only the units on
the Y-axis change since both series of data (Buf50 m and
Thiessen) are indexed to their respective means. Both
series show that the similarity is above average for
Fig. 7. Histogram of the number of parcel neighbours for all parcels for
both the Buf50 m and Thiessen methods.
C. Schmit, M.D.A. Rounsevell / Agriculture, Ecosystems and Environment 115 (2006) 113–127122
Fig. 8. Similarity between neighbouring parcel pairs (expressed as the I1
index) as a function of distance between farms, Thiessen method compared
to Buf50 m method.
Fig. 9. Similarity between neighbouring parcel pairs (expressed as the I1
index) as a function of distance between farms, according to the different
levels of certainty associated to the geocoded farm locations.
Table 5
Summary of the coefficients of the linear regressions for ‘‘distance between
farms’’ inferior to 1000 m
Method Subset a b1 R2
Buf50 m All 1.2805*** �0.00043*** 0.89
Thiessen All 1.1640*** �0.00019* 0.52
Buf50 m MLOK � 9 1.3155*** �0.00051*** 0.86
Buf50 m MLOK � 15 1.3378*** �0.00057*** 0.87
Buf50 m Grass Excl. 1.1399*** �0.00023* 0.37
Buf50 m Grass Excl.
and Dff > 0
1.1144*** �0.00018 0.32
Significance of the coefficients is marked with stars: *** = P < 0.001;** = P < 0.01; * = P < 0.05. For the subset variable: all = all neighbouring
parcel pairs cultivated by different farmers; Dff > 0 = ‘‘distance between
farms’’ is strictly greater than zero metres.
‘‘distance between farms’’ inferior to 700 m. For the
‘‘distance between farms’’ inferior to 1000 m, the linear
trend for the Buf50 m method was characterised by the
equation Si(I1) = 1.2805 � 0.0004dist, with an R2 value of
0.89, whereas for the Thiessen method, the trend was
defined by Si(I1) = 1.1640 � 0.0002dist, with an R2 value
of 0.52. Both the a and b1 coefficients and the R2 value were
lower for the Thiessen method than for the Buf50 m
method. The linearly decreasing trend with increasing
distance between farms is not as well defined for the
Thiessen method as for the Buf50 m method. Overall, the
Thiessen points show a higher variability than the Buf50 m
points (Fig. 8). Nevertheless there is still a trend, with an
above average similarity for neighbouring parcels culti-
vated by farmers who live close to one another.
3.3.3. Uncertainty linked to the geocoding of the farms
The subsets MLOK � 9 and MLOK � 15 are subsets
of the neighbouring parcel pairs based on a judgement of
the uncertainty of the method used to georeference the
farm locations. MLOK � 9 means that the farms of both
parcels have at least a fair location (LOK variable value of
3) or one farm has a strange location (LOK = 2) and the
other one is geocoded perfectly (LOK = 5) (refer to
Table 1). Filtering the neighbouring parcel pairs according
to MLOK � 15 reduces the size of the dataset, but only
neighbouring parcel pairs are used for which the
uncertainty associated with the geocoding of farm loca-
tions is very low.
The two subsets are compared with the whole dataset in
Fig. 9. A similar trend in the first 1000 m ‘‘distance between
farms’’ can be observed for the three data series. Linear
regression on the ‘‘MLOK � 9’’ subset for the ‘‘distance
between farms’’ inferior to 1000 m gave the equation
Si(I1) = 1.3155 � 0.0005dist, with an R2 value of 0.86. The
‘‘MLOK � 15’’ subset resulted in the equation Si(I1) =
1.3378 � 0.0006dist with an R2 value of 0.87. The increased
certainty in the geocoding of the farm locations results in
increased similarity between neighbouring parcel pairs for
farms that are very close to one another (‘‘distance between
farms’’ < 100 m) and it amplifies the slope of the linear
trend within the first 1000 m ‘‘distance between farms’’ (a
and b1 coefficients of Eq. (3)). Filtering the data according to
the confidence in farm location emphasized the general trend
observed in the complete database, but does not change the
basic conclusions from the previous analyses.
Table 5 compares the linear trend adjusted through the
similarity points for the ‘‘distance between farms’’ inferior
to 1000 m. Independent of the method chosen, the trend
shows that parcels of farmers who live close to one another
are more similar than parcels of farmers who live further
apart. The linear trend is clearest for the Buf50 m method for
all neighbouring parcel pairs (highest R2 value). The
Thiessen method gives a much lower intercept (a) and
slope (b1), due to the fact that the distance between
neighbouring parcels is more variable for the Thiessen
method than for the Buf50 m method. Excluding parcels of
farms with an uncertain geocoded farm location results in a
C. Schmit, M.D.A. Rounsevell / Agriculture, Ecosystems and Environment 115 (2006) 113–127 123
Table 6
The cross-tablulation matrix of the similarity of unique neighbouring parcel
pairs (cultivated by different farms; grassland parcels excluded) vs. the
similarity in the communes where the farms of the neighbouring parcel pairs
are located
Communes
of farms
Neighbouring parcel pairs land use (grassland excl.)
Different Same Total
Different 6038 1472 751029.94 7.30 37.24
80.40 19.60 100.00
37.63 35.73 37.24
Same 10007 2648 1265549.63 13.13 62.76
79.08 20.92 100.00
62.37 64.27 62.76
Total 16045 4120 2016579.57 20.43 100.00
79.57 20.43 100.00
100.00 100.00 100.00
The upper numbers of each entry (in bold) give the absolute frequencies, the
second numbers (in normal font) give the percentages of all observations
(20,165), the third numbers (in italic) give the percentages of the row totals, the
fourth numbers (also in normal font) give the percentages of column totals.
higher intercept and slope because parcels of farms left in the
dataset are more clustered around the farm buildings.
3.4. Exclusion of grassland
In Fig. 10, the parcels with permanent grassland were
excluded from the analysis. Without permanent grassland,
the linear trend for distance between farms almost
completely disappears. For the distance between farms
inferior to 1000 m, an R2 value of 0.37 was found for the
line (Si(I1) = 1.1399 � 0.00023dist) adjusted through
the similarity points. The b1 coefficient is barely
significant at the 0.05 level. Within the first 1000 m, only
those parcel pairs cultivated by farms less than 100 m
apart had a similarity index I1 between parcel pairs greater
than 1.15.
For 294 out of 25,645 unique neighbouring parcel pairs,
the distance between farms is zero. This can happen when a
farmer makes two separate declarations for exactly the same
farm, for example, when a husband and wife both declare a
part of the parcels they cultivate together. Therefore, when
two farms were declared with a ‘‘distance between farms’’
equal to zero, they were considered to be a single farm.
These parcel pairs were then excluded from the dataset
without grassland (‘‘farm distance >0 m’’ in Fig. 10). For
this dataset, the b1 coefficient of the equation
Si(I1) = 1.1144 � 0.00018dist fitted through the similarity
points is not significant, even at the 0.05 threshold, and the
R2 falls to 0.32.
A test was also undertaken of the similarity of
neighbouring parcels with respect to the similarity of the
communes where the farms are located. Only non-grassland
parcel pairs cultivated by different farmers were considered.
Parcel pairs cultivated by farms located in the same
commune were slightly more similar (20.92%) than those
cultivated by farms located in different communes (19.60%)
Fig. 10. Similarity between neighbouring parcel pairs (expressed as the I1
index) as a function of distance between farms, comparing a subset of the
neighbouring parcels pairs, where grassland is not included, to the set
including all neighbouring parcel pairs.
(Table 6). The x2-test is significant at the 0.05 level, but not
at the 0.01 probability threshold.
When all grassland parcels were excluded from the
dataset, the relationship between the similarity of neigh-
bouring parcel pairs and the distance between farms almost
completely disappeared. The slope and the R2 value of the
linear trend were low (Table 5) and the b1 coefficient was
hardly significant at the P < 0.05 level. Similar results were
found when the similarity between parcels was compared to
the similarity between the communes of the farm locations.
Grassland is the principal land use responsible for the
observed higher similarity of parcels with respect to the
spatial proximity between farmers.
In analysing neighbourhood influences on criminology,
Elffers (2003) showed that distance to the city centre is an
important explanatory variable. Moreover, neighbourhoods
that are geographically adjacent have values of distance to
the city centre that are similar. Therefore, the spatial
autocorrelation that occurs in the dataset has nothing to do
with the mutual influence of neighbouring areas, but only
with a common underlying variable (distance to the city
centre) (Elffers, 2003). An analogous situation appears
relevant to the results presented here. A previous study
(Schmit et al., 2006) showed that the occurrence of
permanent grassland is strongly related to the distance of
the parcel to the farm. Grassland parcels are preferably
located close to farms and so the distance to farms is an
important explanatory variable for the parcel land use.
Furthermore, for all neighbouring parcel pairs, the ‘‘distance
from farm to parcel’’ and ‘‘distance between farms’’ are not
completely independent variables. There is a strong
correlation between ‘‘distance between farms’’ and ‘‘dis-
tance from farm to parcel’’ (correlation coefficient of 0.64,
C. Schmit, M.D.A. Rounsevell / Agriculture, Ecosystems and Environment 115 (2006) 113–127124
3 For example, climate varies very little across the study area, and the
differences must be minimal between adjacent parcels.
significant at P < 0.001). Thus, for two neighbouring
parcels of grassland, there is a high probability that the
farms owning these parcels are located in close proximity to
them. As a consequence there is a high chance that the farms
cultivating these neighbouring parcels are also close to one
another. By comparing neighbouring parcel pairs, it was
possible to control for the variability in the biophysical
space, but not for the variables related to relative space (i.e.
the distance of the parcels relative to the farm). Farm
location itself becomes an important determinant of
agricultural landscape structure.
Thus, there are two possible processes that can explain
the observed land use pattern. Neighbouring grassland
parcels are more similar than other crops either because
farmers imitate one another or because parcels are located
close to the farm and farmers prefer these parcels to be in
grassland. Based on Schmit et al. (2006), the second option
seems to be more likely and the analysis presented here does
not support the case for imitation.
This is a case of equi-finality, which probably results
from the hierarchy of processes that affect land use decision-
making. Purely physical factors determine the potential land
use space. Climate, soils and topography limit the number of
choices a farmer has concerning the land use on a particular
parcel. Economic factors then influence the exact choice of
land use, usually within the objective of maximising profit
and minimising risk (Rounsevell et al., 2003).
It appears that imitation does not affect land use patterns
directly. However, imitation of neighbouring farmers’
management options concerning land use may be a way
of confirming previously taken decisions about land use. A
farmer, facing alternative choices of land use that are
possible, economically profitable, equivalent in terms of
environmental impacts (sustainable development), might
therefore imitate neighbouring farmers to choose between
two options, that are similar form an economic perspective.
Both of these imitation processes could explain the
observation of slight similarity between parcels, but
imitation is not the major driver of agricultural land use
patterns in the study region.
3.5. Limitations of the method
3.5.1. Neighbouring parcels
The Buf50 m method to determine neighbouring parcel
pairs performed better than the Thiessen method. For the
Thiessen method, the distance between neighbouring
parcels was more variable and could be very large. Isolated
parcels were linked to the closest neighbouring parcels,
parcels that are sometimes several kilometres away. Over
larger distances, the physical characteristics of the
environment can no longer be considered to be identical,
which was an implicit assumption in the parcel comparison
methodology.
With the Buf50 m method it is reasonable to assume
that the physical characteristics of neighbouring parcels are
very similar,3 although this does not completely exclude the
possibility that the physical characteristics may vary
between adjacent parcel pairs. Soils, for example, are not
homogeneous over the study area and may be different
between adjacent parcels, modifying a farmer’s crop
choices. In the least favourable areas, parcels may be more
similar because the physical environment restricts crop
growth to a single crop, e.g.: grassland on wet soils in valley
bottoms (Souchere et al., 2003).
An alternative method for defining neighbouring parcels,
based on raster neighbourhoods was not taken into account,
even though the majority of land use change studies, as well
as most cellular automata and agent-based models work with
land use data in raster format (for examples, see Engelen
et al., 2002; Berger, 2001; Batty et al., 1997; Veldkamp and
Fresno, 1996). Raster data were not, however, used in this
study as they have a number of important limitations.
Technically, defining the neighbourhood of a raster cell is
straightforward, using either a Von Neumann (4 adjacent
cells) or a Moore neighbourhood (8 adjacent cells), or even
larger neighbourhoods, e.g. 196 cell neighbourhoods were
used in the Murbandy and Moland –CA’s (Engelen et al.,
2002). Depending on the raster resolution, however, large
parcels may be divided into several grid cells, or smaller
parcels may not be represented at all and the boundaries of
individual parcels cannot be distinguished. Raster cells do
not correspond to any functional unit in reality; farmers
make land use decisions with respect to parcels and not for
grid cells. Moreover, agricultural parcels differ in size. For
statistical analyses, working with a raster dataset at a
resolution lower than the parcel size increases the number of
observations, which leads to an overestimation of the
neighbourhood effect (due to spatial autocorrelation).
Furthermore, alternative raster representations alter the
composition and/or structure of the landscape (Schmit et al.,
2006). This implies that CA and/or ABM based on raster
data are not appropriate for studying the effects of imitation
on agricultural land use patterns.
If, as presented here, the role of imitation is hardly
significant for vector data, it seems optimistic to hope that
raster data would be any better at representing farmer
imitation. Moreover, it is possible that the commonly
observed neighbourhood effect is a function of the raster
data representation rather than reflecting any inherent
processes. This has important implications for neighbour-
hood-based agricultural land use change models.
3.5.2. Similarity
The dataset used in this study distinguished between 43
different agricultural land use classes. The number of classes
considered has an impact on the similarity between
neighbouring parcels. The larger the number of classes,
the lower the random probability of having two neighbour-
C. Schmit, M.D.A. Rounsevell / Agriculture, Ecosystems and Environment 115 (2006) 113–127 125
ing parcels that belong to the same class.4 Also, the 43
crop classes used here would probably be too numerous for
land use modelling purposes. However, 12 crops make up
90% of all parcels (see Appendix A). Minor crops were not
excluded from the analysis because often it is these minor
crops that are a clear sign of farmer imitation through the
process of innovation diffusion (Ryan and Gross, 1943;
Hagerstrand, 1967). The results of the imitation analysis
would not have varied greatly with the use of only the 12
most common crops.
A major limitation of the method is that similarity was
based on crops rather than on crop rotations. Attempts at
regrouping crops according to their rotations were unsuc-
cessful because of the large number of possible crop
rotations. In the study area, crop rotations commonly have a
periodicity of 3–5 years with sugar beet, maize or chicory in
the first year, followed by winter wheat in the second year
and winter barley, potatoes, fallow, flax or peas in the third
year. However, in addition to this several further possibilities
exist. Crops such as maize may be used in mono-culture as
well as in rotation. Multi-annual parcel data might allow a
‘‘sugar beet–winter wheat–potato’’ rotation to be separated
from a ‘‘chicory–winter wheat–flax’’ rotation, but this would
still not be straightforward as several crops are grown in
several different rotations. It is, however, at all possible with
data for a single year. Because of the diversity and
complexity of rotations, the results of this analysis should
be considered with great care. The method, however,
remains an appropriate means of gaining insight into
agricultural land use patterns that is applicable beyond the
study area presented here.
3.5.3. Social distance
Socio-informational networks of farmers are not neces-
sarily best characterised by the Euclidian distance between
farm locations or the farm location within an administrative
unit. A growing body of literature argues that traditional
family and social networks are less significant in today’s
society as a whole (Beck, 1992; Giddens, 1991; Hutton and
Giddens, 2000). Information transmission is not limited to
communication within a network of colleagues, but also
includes the media, farmers’ associations and public and
private advisory services. Furthermore, modern commu-
nication technologies (internet, telephone) have reduced
functional distance. As a consequence, the level of social
interaction may not decrease with increasing distance
between farms.
A fundamental principle of human communication is that
the transfer of ideas occurs most frequently between
individuals who have similar social profiles in terms of
attributes, beliefs, education, social status and the like
(Rogers, 1983). Applied to farmers, this would suggest a
4 For example, in a landscape composed of parcels of only two agricul-
tural land use classes, each covering half of the study area, spatially-
distributed at random, the similarity between neighbouring parcels is likely
to be around 50%.
higher probability of interaction between individuals with
similar farm typologies. It is possible that a potentially
imitating farmer would assess how far a ‘‘model’’ farmer’s
situation is similar to his own and, hence, how useful
imitation would be (Polhill et al., 2001). A farmer
specialised in field cropping is more likely to imitate a
farmer with the same typology rather than someone
specialised in livestock grazing. Family links and the level
of education are also likely to influence the social network of
the farmer. An attempt was made here to classify farms into
different typologies, based on the land use of the parcels.
Without additional socio-economic data, however, no clear
farm typologies could be distinguished, and the farm types
identified were greatly dependent on the choice of the
classification method.
3.5.4. Temporal dimension
The current analysis was based on a spatial snapshot of
the study region and the temporal dimension was not
taken into account. Imitation of neighbours is a process
that unfolds in both time and in space. The ‘‘temporal
footprint’’5 of farmer imitation on agricultural landscapes
may be more important than the ‘‘spatial footprint’’. The
analysis presented here was limited to a particular region
and to a particular moment in time. A landscape in
transition could reveal a spatial footprint of imitation on
land use patterns that is more important. Moreover, the
agricultural landscape of the Dyle catchment has been
stable in recent years (Schmit et al., 2006). In the future,
policy and climate change may force farmers to adapt
their land use to new conditions. During these transition
phases, the role of farmer imitation may become more
important.
4. Conclusion
The work reported here has attempted to answer the
question, to what extent does farmer imitation leave an
observable footprint on agricultural landscapes? An alter-
native method not based on farmer interviews, but on spatial
parcel and farm location data showed considerable potential
in addressing this question, but also some important
limitations. Results of the newly developed methodology
suggest that imitation is not an important determinant of
agricultural land use patterns in the Dyle Catchment.
Independent of the method or the subset used, the analysis
showed that neighbouring parcels cultivated by farmers who
live close to one another are very slightly more similar than
neighbouring parcels cultivated by farmers who live further
apart. The opposite trend was not observed. The main crop
responsible for the observed trend was grassland. Grassland
has a spatial distribution that is characterised by its relative
5 The term ‘‘temporal footprint’’ refers to the timing of land use change,
for example to ‘‘when’’ farmers first adopt new crops.
C. Schmit, M.D.A. Rounsevell / Agriculture, Ecosystems and Environment 115 (2006) 113–127126
location with respect to a farm arising from accessibility
considerations by farmers rather than imitation. Results
suggest that including social behaviour in physical and
economic models of land use change would not, therefore,
add much to the explanation of observed land use patterns in
this region and for this moment in time.
The results of the analysis need, however, to be
considered with caution because of the limitations of the
proposed methodology. Comparison of neighbouring par-
cels did not allow all factors to be controlled that influence
agricultural land use, such as the distance of parcels to farm
for example. Further analysis and understanding of the
drivers of agricultural land use decisions may help to isolate
the effect of imitation. Another limitation of the method was
that similarity was defined using crop classes rather than
crop rotations. It might be possible to use multi-annual
parcel data to overcome this problem, so that crop rotations
can be identified, but such an approach would not be
straightforward given that the same crop can occur in several
different rotations.
This article presents, therefore, a methodology based on
observed land use data that is an alternative to social survey
based studies of farmer behaviour. The approach seeks to
apply hard methodologies to soft sciences, and may
contribute to the further development of cellular automata
and agent-based land use change models. For this purpose,
the analysis of time series of the same landscape is
preferable, in order to gain insight not only into the spatial,
but also into the temporal dimension of the effects of farmer
imitation on agricultural landscapes.
Acknowledgements
The authors wish to thank first the EU ACCELERATES
project (contract no. EVK2-CT2000-00061) and the
Luxembourg Ministry of Culture, Higher Education and
Research for funding this research, and the Direction
General de l’Agriculture (DGA) of the Walloon Region in
Belgium for the IACS parcel data and farm addresses.
Specifically, thanks are extended to Mr. Mokadem of the
Ministry of Agriculture for the description of available
datasets in the Walloon region and Mr. Dautrebande of the
Centre de Recherche Agronomique (CRA) of Gembloux
for supplying samples of IACS data for Belgium. The
authors would also like to acknowledge the contribution of
Dr. Isabelle La Jeunesse in the creation of the GIS database
and Mr. Thomas Crepin for his help in the geocoding
process.
Appendix A
Table with number of parcels, percentage of all parcels
and cumulated percentage of all parcels, for all land use
classes present in the Dyle Catchment
Rank
Land use (crop) Parcels Percentage Cumulatedpercentage
1
Winter wheat 3809 23.14 23.142
Permanent grassland 3136 19.05 42.183
Sugar beet 2342 14.22 56.414
Silage maize 1876 11.39 67.805
Winter barley 830 5.04 72.846
Fallow (grains) 594 3.61 76.457
Potatoes 512 3.11 79.568
Fallow (grains and pulses) 493 2.99 82.569
Non-permanent grassland 435 2.64 85.2010
Chicory 397 2.41 87.6111
Spring barley 265 1.61 89.2212
Grain maize 229 1.39 90.6113
Fallow (natural cover) 166 1.01 91.6214
Other fallow 145 0.88 92.5015
Oats 138 0.84 93.3416
Spring wheat 107 0.65 93.9917
Other (tobacco, hops, . . .) 107 0.65 94.6418
Flax 99 0.60 95.2419
Peas 88 0.53 95.7720
Mixed fallow 78 0.47 96.2521
Forage beet 75 0.46 96.7022
Other fodder 72 0.44 97.1423
Pulses 67 0.41 97.5524
Market gardening 67 0.41 97.9525
German wheat 56 0.34 98.2926
Field beans 56 0.34 98.6327
Dried peas 45 0.27 98.9128
Triticale 43 0.26 99.1729
Oilseed rape (winter) 43 0.26 99.4330
Winter oilseed rape 35 0.21 99.6431
Non-food horticulture 11 0.07 99.7132
Fruit crops 11 0.07 99.7833
Lucerne 10 0.06 99.8434
Dried beans 8 0.05 99.8835
Beans 6 0.04 99.9236
Other grains 3 0.02 99.9437
Clover 3 0.02 99.9638
Wood 2 0.01 99.9739
Oilseed rape (spring) 1 0.01 99.9840
Sunflower 1 0.01 99.9841
Linseed 1 0.01 99.9942
Fodder carrot 1 0.01 99.9943
Other 1 0.01 100.00Total
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