Knol,, Onno M. with Geert O. Nijland, Marcel W.L. Bovy, Pieter Jan M.T. Stallen, Floor M. Brouwer and Paul J.J. Veenendaal, "Modeling Complex Economic-Ecological Interactions in the Agricultural Sector in the Netherlands", 1990
In the Netherlands, ammonia emissions from agriculture contribute significantly to the acidification of soil and water. A 50-70 % reduction of these emissions within the next ten years is one of the great challenges for agricultural practice. This paper presents an outline of a combined system dynamics-optimization model of this problem, which will be used to study the effect of three different abatement scenarios.A concise analysis of the acidification problem is given. The main causes of the current environmental problems of the agricultural system are described.Next the choice of modeling techniques is discussed. System dynamics was applied because of the many (non-linear) interactions and delayed feedback relations in the agricultural system. The flexible responses to policy measures shown by the system’s actors in the past, urged including economic optimization procedures in the model.Some remarks are made on technical problems, using Professional DYNAMO linked with a FORTRAN optimization module.The model contains an integrated description of the ecological problem in its economic context, with links to the related policy field of eutrophication. Interaction with reference groups consisting of experts and governmental officials, and interviews with representatives of interest groups have greatly contributed to the development of the model.Only tentative conclusions can be presented at this stage, as results are still being worked on. However, a better understanding of the acidification problem had been reached, by the reference groups and the researchers. An interesting aspect is the link between emission reduction policy scenarios and possible shifts in land-related agricultural activities.