Identifying Optimum Strategies for Land Management Adaptation to Climate Change - A Multiobjective Approach

Climate change is likely to alter the conditions for agricultural production with distinct regional patterns, which necessitates adaptation measures that are adjusted to local conditions, but adaptation to maximize production may increase environmental impacts. The objective of this research is to identify sustainable regional land management adaptation strategies to maximize agricultural productivity, while minimizing environmental impacts such as nutrient leaching, soil erosion and an excessive use of water resources. The study area is the Broye catchment in Western Switzerland, where water shortage is common and irrigation is already applied regularly. For this region, the generic crop model CropSyst was calibrated for the most common field crops and for grassland. To account also for livestock production, a simplified livestock model based on empirical functions was developed to estimate water consumption, nutrient loads and forage requirements. The crop model in connection with the livestock model can be applied to test a multitude of management scenarios under different conditions including soil type, slope, or current and future climate. By integrating these models into a multi-objective spatial optimization routine, we can produce a series of optimum trade-off scenarios for regional adaptation strategies with varying weights for development goals (i.e. agricultural productivity, water saving, soil protection). A selected series of such trade-off scenarios can be presented to regional planners as possible goal scenarios, showing which adaptation strategies should be promoted in order to achieve most important regional planning goals (e.g. maintain productivity while minimizing water use and environmental impact).