Parametrisation of Individual Leaf Approach for Pearl Millet and Sorghum

Abstract

For the simulation of canopy leaf area development, the released sorghum model uses the total plant leaf area (TPLA) approach. This approach has descriptive parameters that capture the shape of the leaf area development function, and relies on a user defined tiller number per plant. The TPLA approach is essentially an integration of the individual leaf area (ILA) approach. In order to bring simulation of canopy leaf area development closer to the plant functionality, we attempt to develop algorithms for canopy predictions based on individual leaf area function which is a necessary prerequisite for implementation of dynamic tillering module. Since tillering is one of the key environmental adaptive mechanism of sorghum&pearl millet (e.g. vanOosterom et al 199x, Jordan et al 200x), availability of a dynamic tillering module will be a crucial feature vastly improving mechanistics of sorghum and pearl millet crop predictions and so the overall value of such modelling tool. Also, because pearl millet crop is very similar to sorghum, the pearl millet module is currently being incorporated into the sorghum/maize modelling framework. If successful, the improved tool should allow, for the first time, reliable comparison of pearl millet, sorghum and maize using the up-to-date research from the same modelling platform and so improve the APSIM model value as a decision making support in breeding programmes around the globe.