Building and evaluation of a dynamic model for assessing impact of smallholder endowments on food security in agricultural systems in highland areas of central America (SASHACA)

Smallholder agricultural systems have an important role in world food production. Agricultural smallholders in highland areas of the Mesoamerican dry-corridor are central to improve farming systems. The key issue is that the subsistence smallholders are joint producer-consumers, with insufficient food production due to extreme environmental and weather conditions or incomes to supplement their own production from market sources. Modelling offers an approach for testing and improving knowledge about complex systems. The aim of this paper is to describe and assess a biophysical and socio-economic model of the smallholder agricultural systems based on maize-bean intercropping in highland areas of Central America. A Vensim® DSS system dynamics model was developed for assessing the impact of Smallholder endowments on food security and to identify critical points to achieve sustainable food security and poverty alleviation in Agricultural Systems in Highland Areas of Central America (SASHACA). The SASHACA model integrates scientific and practical knowledge of crop management, labour, soil water content, soil nitrogen, food consumption and economic components of the system. Model evaluation was conducted through a wide set of tests for assessment of dynamic models and statistical comparison of simulated versus observed data derived from surveys. The model simulates realistic outputs and presents logical behavioural representation. The maximum relative uncertainty of output variables ranged from 30% to 53% for univariate and multivariate sensitivity analyses respectively. The model proved to be adequate for assessing food security under scenarios in low data availability areas. The SASHACA model could be adapted to simulate a wide range of smallholder agricultural systems in highland areas of Central America, and potentially in other locations.