Modelling the dynamics of agricultural development at farm and regional level

Policy making, to enhance sustainable agricultural development, requires insight in the complex dynamics of agricultural systems at the farm and regional level. These include the way farmers take management decisions, the effects of these decisions on soil fertility and crop and animal production and the consequences of these production levels for prices at regional level, which in turn influence decisions at the farm level. Moreover, interactions between farms should be taken into account in an environment were an expanding agriculture is facing the limitations of space. This paper discusses a number of modelling approaches that are used to support decision-making on these issues. The paper argues that the study of such systems requires the use of non-linear dynamic models that allow simulation of the system in a qualitative way, based on a description of the underlying processes. The approach is illustrated with a regional model that has been developed to simulate agricultural development in the Koutiala region in the south-western part of Mali. The paper shows how the approach helps to better understand the dynamics of this system and how it may help to explore the effect of policies on sustainability. Finally the strong and weak points of the approach are discussed. (C) 2003 Elsevier Science Ltd. All rights reserved.