Assessment of interactions between land use change and carbon and nutrient fluxes in Ecuador

Changes in land use affect input and output fluxes of nutrients and carbon in soils and vegetation. This can lead to changing soil fertility, which in turn will affect biomass production and human decisions in land management. Next to a local impact on land quality, changing biogeochemical cycles can also have a global impact through the emission of greenhouse gasses. The drivers and processes of land use change related nutrient and carbon fluxes are scale-dependent. In this paper, we propose a conceptual dynamic approach (CLUE-Nuts) for the modelling of the interaction between land use change and nutrient and carbon fluxes. It is based on the integration of a spatially explicit multi-scale land use change model (CLUE) with a nutrient monitoring approach (NUTMON). Near future changes in the areas of agricultural crops and natural vegetation can be modelled in scenarios and their effects on soil nutrient and carbon status estimated. Feedback mechanisms for major crops can be included, taking into account that matter fluxes can alter carbon and nutrient stocks considerably. The feasibility of the new approach is illustrated with data from a case study for Ecuador. From these preliminary results it is concluded that CLUE-Nuts is a powerful tool to predict crop specific near future land use and related nutrient fluxes. The suggested feedback mechanisms are suitable for major crops with excellent data representation, and are subject of further refinement and research. (C) 2001 Elsevier Science B.V. All rights reserved.