Exploring the impacts of field interactions on an integrated assessment of terraced crop systems in the Peruvian Andes

This study explores a modelling approach to investigate the interactions between terracing, water availability, and land use decisions and farmers' incomes in a study area in the Peruvian Andes. We tested the hypothesis that these interactions affect the simulated spatial distribution of impacts because of technology changes as well as aggregate impacts. To do this a model simulating water redistribution at the catchment scale is linked to a site-specific model of land use and management, using the trade-off analysis modelling system. The results indicate that the interactions do not affect the aggregate impacts but they do result in different spatial patterns of land use and farm income in the study area. The simulated effects of terraces on productivity are affected by the spatial patterns of terracing. These findings suggest that, although field-level interactions may average out in aggregate analysis, the effects they have on the spatial pattern of land use allocation and income may be relevant for analysis of environmental impact and equity studies in which the spatial distribution of effects is important