Mechanistic modelling of soil-plant-atmosphere systems.

Based on the concepts of mechanistic mathematical modelling the foundations of plant growth models are explained and some examples provided. It is illustrated how model modularity can be helpful to describe more complex eco-systems and how mechanistic plant growth models can be based on a multitude of sub-models that describe the important eco-physiological processes needed to determine plant growth dynamics. Modelling concepts for the simulation of phenological development, of photosynthesis, of nutrient allocation and of water and solute transport within the soil–plant continuum are presented. Moreover, two newly developed mechanistic plant growth models will be introduced. One model is the individual-based model PLATHO, which focuses on the description of the plant internal regulation of carbon allocation and nutrient uptake, and the other model is the stand model BALANCE, which in particular considers allocation strategies of trees in dependence on competition within the canopy