Alternative Approaches to the Economics of Soil Nutrient Depletion in Costa Rica: Exploratory, Predictive and Normative Bio-Economic Models

This chapter discusses three methodologies to analyse land use with respect to income generation and sustainability in the Atlantic Zone of Costa Rica: the explorative SOLUS methodology,the predictive UNA-DLV methodology,and a normative optimal control approach. Each methodology may be classified as bioeconomic; the first two are single period optimisation models at the regional and farm level,respectively,while the third is a dynamic model at the plot level. The SOLUS and UNA-DLV methodologies incorporate a multi-market structure for commodities produced by a wide spectrum of land use systems with specified technologies. For each of these systems,technical coefficients are generated related to discounted benefits and costs,and to sustainability indicators,including soil nutrient depletion. The optimal control model is confined to a pasture plot with cattle,property of a single farmer,and analyses the inter-temporal trade-off between soil nitrogen depletion and net benefits. Apart from assessing the ‘economic benefit - sustainability’ trade-off,all methodologies are capable of analysing the effects of technological change. After providing some example results,the chapter concludes with a comparison of the relative merits of each methodology.