Timothy growth in Scandinavia: combining quantitative information and simulation modelling

Timothy (Phleum pratense) is the most widely grown sown grass species for s ilage and hay production in the Nordic countries; it is also common in many other areas with a cold maritime climate. Research on timothy has identifi ed many environmental factors and plant characteristics that determine timo thy growth. However, much of the literature that analyses timothy growth pr esents only qualitative estimates of the importance of the different growth -determining factors. Here we present a review of quantitative information on timothy. Moreover, we analyse to what extent this quantitative informati on is sufficient to permit the construction of a simple process-based model of timothy growth. We then use such a model to identify the major growth-d etermining factors. Simulations with the model showed that the major proces ses to be elucidated in future research on timothy are tillering dynamics a nd the formation and loss of leaves from tillers. We conclude that a combin ation of literature review and analysis by means of simulation modelling, s uch as we attempted here, is an effective approach to identify and prioriti ze research goals. (C) New Phytologist.