Wetenschap - 21 maart 1996

Modelling is the bridge between theory & practice

Modelling is the bridge between theory & practice

Rudy Rabbinge is a dynamic and enterprising scientist. Sometimes a little too optimistic perhaps, and very hard working. Last year he took up only 40 hours of vacation," says Professor J. Goudriaan of the Department of Theoretical Production Ecology of his colleague. The fact that Professor Rabbinge has worked at the university for 25 years was cause for the Graduate School for Production Ecology to organise a mini-symposium.


One of the main aims of theoretical production ecology is the development of simulation models using a system analysis approach in order to gain better insight into crop production. Rabbinge is regarded as a worldwide authority in this field. He is chair of the Department, one of the initiators of the C.T. de Wit Graduate School for Production Ecology and is a member of the Netherlands Scientific Council for Government Policy.

Bridging the gap between theory and practice in the field of production ecology was the issue at stake during the symposium held last Thursday March 14. During his opening address Rector Karssen explained that the invited speakers had been asked to elaborate on issues of importance in Rabbinge's work.

P. E. Kenmore began the session by tackling the crop protection level: It is important to realize that practical integrated pest management (IPM) is about farmers with problems, not just crops in distress."

He gives an example of a farmer applying insecticides to a rice crop, affected by bacteria. Ninety percent of the estimated yield can be harvested even if pesticides are not used, and application of nitrogen would save most of the remaining ten percent. Kenmore, who works for the FAO in the Philippines, is involved in a regional programme assisting Farmers Field Schools (FFSs). These are set up as a forum where farmers can discuss issues concerning crop production. Farmers collect data, undertake experiments and discuss the results and possible solutions. They can then take action themselves or call in assistance from outside. At present FFSs operate in over 30,000 villages in Asia. Farmers from one school become trainers in other villages, thus building up a network of IPM groups. Each FFS has its own resource base of local expertise and knowledge.

Key agents

Kenmore believes that crop simulation models developed by agricultural scientists could provide assistance to farmer initiatives in understanding the impact of the factors affecting the yields on their farms.

G. L. Hammer, an Australian agricultural system researcher, emphasizes the crucial role of the farmer, who in effect is the manager of a complex agricultural system. Hammer explains that in order to improve agricultural practices, it is essential to consider the farmer as a key agent, who should be engaged in the farm system research. According to Hammer, Modelling provides a powerful means to evaluate potential decision options and generate discussion among farmers about agricultural practices."

According to Hammer scientists' work is about understanding, whereas engineers are true problem solvers. That difference has to be bridged. You have to use understanding to predict potential problems and changes in the farm system. The only way you know that you have reached that bridging position is when you are continuously kicked by all parties."

Agricultural research

C.H. Bonte-Friedheim, director of the International Service for National Agricultural Research (ISNAR) elaborates on the work of the Consultative Group on International Agricultural Research (CGIAR), of which ISNAR is member. He explains that while research originally focused on food production, now an approach has to be developed to link poverty alleviation and food production with sustainability. In 1990 the ecoregional concept arrived. Bonte-Friedheim admits: Ways of achieving sustainable agriculture based on sound policy and technologies for managing the natural resource base are long overdue on the global research agenda." Applying ecoregional concepts will be possible through partnership on an equal basis of agricultural research institutions at all levels. He believes that agricultural system thinking stands a great chance of success. He characterises Rabbinge as just this sort of modeller who understands the importance of political empowerment both of science a
nd of farmers.

One result of Rabbinge's work with the Scientific Council for Government Policy is the report Ground for choices, an exploration of future land use options in Europe. In the study Rabbinge discloses that the increasing productivity of European agriculture will make land available, which, for instance, could be designated for nature development. Rabbinge is also advisor to the Dutch Minister for Agriculture, Van Aartsen. Rabbinge concludes the symposium after expressing his word of thanks: Scientists should not sit in the chair of the policy makers. Policy makers ask for options and not for recipes."

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