Presentation of DEXiPM

Frédérique Angevin, Elise Pelzer, Antoine Messéan

DEXiPM, to design and evaluate innovative crop strategies.

DEXiPM is a multi-criteria model for evaluating the sustainability of cropping systems, based on DEXi technology (Bohanec, 2009). Initially, the model concerns only field crop systems. It was designed for a research audience and aims to evaluate the performance of cropping systems based on the principles of integrated pest management.
This is reflected in the structure of the model by the addition of specific crop protection criteria to strengthen the evaluation on this point and allow fine comparisons of different protection strategies. As the model is used ex ante for the facilitation of design groups, it is entirely qualitative and is characterized by an in-depth breakdown of the tree structure (75 basic criteria and 86 aggregated criteria). This methodological choice was made in order to facilitate the completion of the model by experts when few references are available on the systems to be evaluated. Finally, in DEXiPM, socio-economic criteria related to the extra-parcel context were inserted to evaluate the performance of the systems in their evaluation context. These criteria can then be used to identify the barriers to innovation and to define more appropriate public policies or commodity chain strategies by simulating changes in the context.
DEXiPM is part of the research dynamics of several European projects (ECOGEN, SIGMEA, Endure, PURE) and combines different tools and pre-existing models (MASC, Indigo, Salca,...). The name DEXiPM is a contraction of DEXi, the software for managing qualitative trees, and IPM (Integrated Pest Management)
DEXiPM is an integrated tool for dynamic, multi-criteria, multi-scale and multi-actor design and evaluation. Its strengths lie in the inventiveness it allows in the design of systems, as well as in a flexible evaluation according to the priorities of the different actors.

DEXiPM is registered at the Agency for the Protection of Programs (Paris) under the number IDDN.F.R.001.490014.000.R.P.2009.000.30100.

An inventive model

DEXiPM was designed to help design cropping systems that are truly a break with existing systems, without stopping at economic feasibility criteria. Even if a system is not realistic today, it may become so in the more or less distant future, if certain conditions - economic, social, technical - change.
Such freedom of conception is necessary because the pressures exerted on agriculture, at the national and European levels, impose profound changes in cropping systems. For example, it will not be possible to achieve the objectives of the Ecophyto plan launched in France to reduce inputs without modifying crop rotations, or even introducing new crops, and therefore new sectors.

An evaluation possible from different points of view

DEXiPM allows for an evaluation of the sustainability of systems that is as complete as possible, according to economic, social and environmental criteria. The originality of the model is to make this evaluation flexible according to the criteria of the different actors. In this way, each actor - farmer, distributor, NGO, researcher - can assume his or her choices and measure their consequences in complete transparency. As a result, the model can serve as a basis for discussion between these actors.
Finally, since it is a qualitative assessment, the model can accept gaps in knowledge that are sometimes limited to expert opinion.

A decision tree allowing the three pillars of sustainability to be taken into account

The model is organized in a hierarchical tree in which, as input, 75 basic criteria describe the system.

DEXiPM tree of input parameters
DEXiPM, input parameters tree. © Inrae

The criteria are aggregated, node by node, to arrive at a qualitative estimate of the overall sustainability of the system being evaluated.

DEXiPM output parameters tree
DEXiPM, output parameters tree. © Inrae

The weighting of the criteria

The model allows the introduction of weighting factors for the different criteria, according to the priorities that the user gives them. The actors can thus test several choices and discuss them in all transparency, since the hierarchy given to the different criteria chosen is apparent.

DEXiPM agregation rules
DEXiPM, choice of aggregation rules. © Inrae

In this example, the weighting (green background) is applied at two levels of the tree: at the level of resource use (where the share given to water, energy, soil and mineral fertilization is chosen), and at the level of the evaluation of the overall sustainability of the system studied (here, an equal share is given to environmental, economic and social sustainability, but this is left to the user to decide).
Initially developed for field crop systems, adaptations were then made for field vegetables and for perennial crops (vineyards and apple orchards).

In this folder

The IZI-EVAL interface was developed to facilitate the use of models designed with DEXI. It allows a simplified management of the input and output data of the models, the realization of graphs and sensitivity analyses.

Modification date : 09 May 2023 | Publication date : 27 May 2021 | Redactor : MEANS