Dynamic modelling of resource management for farming systems

Abstract With the rapid development of computer technology, numerous simulation models have been developed for agricultural systems and farms. Nevertheless, most of them are rather appropriate for developed countries as they have considerable data requirements and often aim at optimizing farm resources, excluding the farmer’s household from the system. Yet, the latter is crucial for the understanding of semi-subsistence systems such as those found in developing countries. We present a dynamic model of an agricultural system in the Central Highlands of Nicaragua. It aims at giving a deeper insight into the functioning of the system and the constraints the latter is subject to. Such an approach helps to explain why farmers make certain choices. Although for the study area few data are available, a robust model with a one-day resolution could be designed. For simulation two groups of scenarios were chosen: (a) Minimum farm sizes for the production of a certain food supply (e.g. basic staples) were assessed and the impact of increased fertilizer use was estimated. (b) Monoculture farms were simulated with the main crops of the region. The production of calories, protein and added value were chosen as indicators. We determined the labour requirements for both groups of scenarios. Simulation results show that the latter is a limiting factor. This is true even for farming systems aiming at covering minimum needs (food, elemental health care and schooling) only. We can show that farmers’ strategies (e.g. crop mix, fertilizer application) are crucial for the system. Last but not least, we produce some evidence for the advantage of the current crop mix in the study region.