Invited Talk: Structural-Functional Model SimRoot and its Applications

SimRoot is a structural-functional model with, in contrast to most structural-functional models, emphasis on the architecture and function of the root system. We use SimRoot as a heuristic tool in our efforts to understand the function of different root traits for acquisition of nutrients and water in low fertility soils and drought environments. We parameterized SimRoot for both maize and bean and are currently able to simulate nutrient uptake for phosphorus and nitrogen in combination with water uptake and photosynthesis. SimRoot is designed to simulate stress responses in a virtual plant with a ´sound´ carbon balance sheet. SimRoot is a modular model and can be run in different configurations. The main modules are root growth and shoot growth modules, carbon module, nutrient and water uptake and stress modules. The carbon module is based on LinTul. Both the Barber-Cushman model and Simunek´s SWMS can be used for simulating nutrient uptake & transport in the soil. Nutrient stress effects growth by reducing for example the leaf area expansion rate or photosynthetic efficiency of the leaves. SimRoot is designed to work with measurable parameters and uses a predictor-corrected integration method to obtain accurate results, even when positive feedbacks are simulated.