Model simulation of effects of changes in climate and atmospheric CO2 and O3 on tuber yield potential of potato (cv Bintje) in the European Union

A simple simulation model for potato growth was improved on the basis of the experimental results from the EU-project CHIP. To test if the model works well for the different CO2 and O3 treatments under a range of environmental conditions in the EU, the experimental results from all treatments at the sites within this project were compared with the simulated results. A detailed analysis was done first for Rapolano, Italy and Tervuren, Belgium. This showed that in general the time courses of the observed CO2 and O3 effects on tuber yields at Tervuren and of the CO2 effect at Rapolano were simulated well. Next, crop variables as observed at the final harvest in all experiments within this project were compared with the simulated results. This showed that the total radiation interception was simulated well. Radiation use efficiency (RUE), however, was simulated well for only half of the sites. As a consequence, total biomass and tuber yields could only be simulated well for all sites, if photosynthetic parameters in the model were calibrated separately for half of the sites. These and other difficulties in the development and testing of the potato model on the basis of the CHIP experimental data set were discussed.