USTED: a methodology for a quantitative analysis of land use scenarios.

Scenarios are a useful tool to study the effects of changes in the socio-economic and/or biophysical environment on agricultural land use. For the analysis of these scenarios an operational methodology, USTED, has been developed. The methodology is based on a linear programming model in combination with GIS, crop growth simulation models, and expert systems. The data requirements include quantitative descriptions of land use systems and technologies, attribute data on such features as prices and chemical compositions, and georeferenced data on farms and soils. Sustainability is incorporated in the methodology by a limited number of quantified sustainability parameters. The linear programming model analyses, on the basis of different farm types, the effect of different scenarios on land use. Customized computer software (MODUS) is used to integrate the different models. The methodology is illustrated with a case study for the Neguev settlement in the Atlantic Zone of Costa Rica.