Mitarbeitende

Climate change signficantly affects agricultural production throughout the world, inter alia with shifts of the suitable areas for certain crops. This includes soybeans, which could become increasingly suitable for cultivation in the northern latitudes of Europe. Soybeans are already grown on the Swiss Plateau on a small scale, but an increase in soybean cultivation is currently witnessed. The objective of this thesis is to assess the impacts of climate change on soybean yields on the Swiss Plateau with a modelling approach. The crop growth model WOFOST was evaluated at two study sites (Reckenholz and Changins) and then applied with climate projection data under RCP4.5 and 8.5. The model was evaluated with yield reference data and measurement data of the leaf area index and soil moisture from Reckenholz 2022. The evaluation showed a satisfactory performance regarding yield simulation, but LAI and soil moisture were not simulated accurately. Based on their simulation performance, the crop parameter files ‘SOY0906.CAB’ and ‘SOYBEAN.W41’ were chosen as inputs for the model application The outputs of the model application focusing on climate impacts differed mainly regarding the two crop parameter files. With crop file w41, a general increase in soybean yield was simulated under climate change scenarios, while with 906, a decline was projected. The main difference between the study sites was, that a higher amount of dry stress days was simulated for Changins, which lead to the conclusion that additional irrigation might become necessary at this site in the near future. In all scenarios and at both locations, a shift towards earlier projected flowering and maturity dates was observed. Due to limitations and uncertainties of the model simulations and climate change projections, further research is recommended. This concerns, inter alia, the parameterization of the model with additional data, and a consideration of CO2 fertilization effects.