Functional-structural plant modelling in crop production

The role acquired by modelling in plant sciences includes integration of knowledge, exploration of the behaviour of the plant system beyond the range of conditions covered experimentally and decision support. The purpose of the model determines its structure. Initially process-based models (PBM) were developed separately from structural (or: architectural or morphological) plant models (SPM). Combining PBMs and SPM into functional-structural plant models (FSPM) or virtual plants has become feasible. This adds a dimension to classical crop growth modelling. FSPM are particularly suited to analyse problems in which the spatial structure of the system is an essential factor contributing to the explanation of the behaviour of the system of study. Examples include intra-specific and interspecific competition phenomena, analyses of mechanisms of physiological response to environmental signals that affect allocation of carbon and nitrogen in the plant, and exploration of alternative, manipulated plant architectures on production of fruits or flowers. Good modelling practice involves different steps in model development. These steps are discussed and include the conceptual modelling, data collection, model implementation, model verification and evaluation, sensitivity analysis and scenario studies.