THE ROLE OF MODELING IN THE QUEST FOR SUSTAINABLE FARMING SYSTEMS

Sustainability in agriculture involves inter-temporal tradeoffs in the use of natural resources. Analysis of sustainbility necessarily invol ves the study of the dynamics of change in the stock of natural resour ces. To understand and analyse sustainability better it is important t o be able to forecast the future consequences of current resource-use decisions. As the time frame involved may be long, and complex interac tions among various parts of the farming systems need to be well under stood, modelling is a good tool for studying such phenomena. Following consideration of the role of various types of models of farming syste ms as substitutes for, or complementary to, real-world experimentation , it is contended that bio-economic simulation models are well-suited for studying sustainability. A powerful tool to evaluate sustainabilit y implications of alternative management practices is provided by the framework of optimal control theory. Some illustrative applications of modelling are presented and possible problems in applying such models in the context of developing countries are presented.