Modelling Root Water Uptake: From 3-D Root Scale Models to 1-D Field Scale Effective Approaches.

Numerous approaches exist to model soil water extraction by plant roots. They mainly differ in terms of dimensionality (from 1-D to 3-D) and in the degree of detail involved in the geometry and hydraulic behavior of roots. One-dimensional models consider 1-D root length density profiles and assume uniform horizontal soil water distribution and are computationally very efficient. On the opposite, very detailed 3-D approaches, which consider explicitly the root architecture and the root water flow, may need more computation power and time. In between these two extreme cases, other approaches exist, which may be equally accurate and less computationally demanding. Our objective is to compare different modeling approaches to data and check how their implicit or explicit simplifications or assumptions affect the root water uptake (RWU) predictions.