Agriculture, Ecosystems and Environment 80 2000 143–158
Adaptation and use of a fuzzy expert system to assess the environmental effect of pesticides applied to field crops
Olivier Roussel
a
, Alain Cavelier
b
, Hayo M.G. van der Werf
c,∗
a
ENSAR, Rennes, France
b
INRA-URIGC, Le Rheu, France
c
INRA, Unité Sol et Agronomie de Rennes-Quimper, ENSAR-65, rue de Saint Brieuc, 35042 Rennes, France Received 22 June 1999; received in revised form 14 January 2000; accepted 3 February 2000
Abstract
Centre d’Etude pour un Développement Agricole Plus Autonome CEDAPA is a group of farmers in Brittany western France which proposes a mainly pasture-based milk and meat production system defined by a set of prohibitions and
obligations. CEDAPA farmers claim that their production system causes less environmental damage than the current systems used by most other farmers. With respect to pesticide effects this claim was examined by using an expert system Ipest,
which reflects the authors’ perception of the potential environmental effect of the application of a pesticide to a field crop. Ipest requires three types of input variables: pesticide properties, site-specific conditions and characteristics of the pesticide
application. It yields four output variables: one reflecting the rate of application of the pesticide, the other three reflecting the risk for three major environmental compartments groundwater, surface water and air. In order to fit the hydrogeological
conditions of Brittany and to decrease dependence on expert judgement, the Ipest system was modified and enhanced. An existing method for the estimation of runoff risk from the field was included. This new version of the expert system, Ipest-B,
was used to compare the environmental effect of pesticide use on winter wheat, silage maize and fodder beet, which overall was largely similar. However, within each of the three crops, large differences occurred from pesticide characteristics, number
of treatments and environmental conditions. This type of analysis helps to identify and recommend the least harmful treatment programmes for each crop. The Ipest system was shown to be flexible, and adaptable to the particularities of Brittany. An
adaptation of the system to other regional conditions should be possible. © 2000 Elsevier Science B.V. All rights reserved.
Keywords: CEDAPA; Decision support; Environmental effect assessment; Expert system; Fuzzy logic; Pesticides; France
1. Introduction
Agriculture in Brittany western France has seen several decades of continuous intensification. As a re-
sult of this farmers in Brittany are among the most pro-
∗
Corresponding author. Tel.: +33-2-23-48-5709; fax: +33-2-23-48-5630.
E-mail address: Hayo.Vanderwerfroazhon.inra.fr H.M.G. van der Werf
ductive in Europe, but their activities cause major en- vironmental deterioration. In particular, the pollution
of water by nitrates and pesticides is a severe problem which has not gone unnoticed by water consumers:
in Brittany per-capita consumption of bottled mineral water is well above the average for France Clément
et al., 1997.
To reduce environmental pollution farmers in Brit- tany try to adapt their production systems. In 1982,
0167-880900 – see front matter © 2000 Elsevier Science B.V. All rights reserved. PII: S 0 1 6 7 - 8 8 0 9 0 0 0 0 1 4 2 - 0
144 O. Roussel et al. Agriculture, Ecosystems and Environment 80 2000 143–158
the Study Centre for a More Autonomous Agricultural Development Centre d’Etude pour un Développement
Agricole Plus Autonome CEDAPA was founded in central Brittany. This group, consisting currently of
about 100 farmers, proposes a pasture-based milk and meat production system Pochon, 1993. The system
should allow a good income and, as the result of a re- duced work load, a better quality of life for the farmer.
CEDAPA further claims that, because of a reduction of external inputs, farms are more autonomous, have
lower costs and cause less environmental damage. CEDAPA farmers follow guidelines concerning pas-
ture and crop management practices, animal feeding and landscape maintenance Pochon, 1998. The pro-
duction system aims at a maximum amount of forage in the diet of the cows, mainly provided by a ryegrass
— white clover sward. This allows a reduction of the amount of concentrated feed needed to complement
the diet.
Within this context, annual crops are grown to provide additional forage during winter. According
to CEDAPA guidelines, the area dedicated to silage maize should not exceed 15 of the total area ded-
icated to pasture and annual forage crops. Silage maize is considered to be a potentially polluting crop
mainly because it does not cover the soil during win- ter and spring, and thus, may favour erosion, runoff
and leaching. More generally, the guidelines limit ni- trogen fertilisation and use of pesticides for all crops,
in order to reduce production costs and pollution risks Pochon, 1998.
In 1993 a research programme Système Terre et Eau was set up to evaluate the CEDAPA production
system. Within this research programme, a study was carried out in 1996 to characterise pesticide use by
CEDAPA farmers. The objectives of this survey were to:
1. Evaluate the way farmers plan their crop pest man-
agement; 2. Evaluate the environmental effect of pesticide use
by CEDAPA farmers. The results of the survey and an evaluation of crop
protection strategies have been reported by Cavelier et al. 1997. The evaluation of the environmental
effect of pesticides used by CEDAPA farmers is the subject of this paper.
This evaluation can be achieved in a variety of ways. For example, it could be based on measurement of
relevant variables or on their estimation by means of a mathematical simulation model Stockle et al., 1994.
Neither of these approaches was used here on the grounds of cost and non-availability of an adequate
simulation model. Bockstaller et al. 1997 proposed a set of ‘agro-ecological indicators’ as an alternative
to measurements and the use of simulation models to evaluate the environmental effects of farming systems.
The term ‘indicator’ has been defined as a variable which supplies information on other variables which
are difficult to access Gras et al., 1989. Indicators synthesise information and can thus help understand-
ing of a complex system Girardin et al., 1999. Sev- eral indicator-type approaches have been proposed to
assess pesticide effects Shahane and Inman, 1987; Levitan et al., 1995; Van der Werf, 1996. Here the
indicator Ipest Van der Werf and Zimmer, 1998 was used, because it takes into account pesticide proper-
ties, site-specific conditions and characteristics of the pesticide application. Ipest is suitable because the in-
put variables it requires are available for the farms and the hydrogeologic conditions of Brittany.
2. Materials and methods
