1] Three dimensional soil-root water transfer models require a fine soil and root discretization in order to obtain accurate results. This goes along with a considerable computational effort. One way of reducing the computational effort is the usage of grid refinement techniques. With such techniques irregular grids are obtained that combine the accuracy of a fine grid resolution with a considerable reduction in computational costs. As a consequence of plant transpiration roots take up water

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... large soil water potential gradients around roots are created. Especially in these regions a fine soil discretization is needed. The root spatial distribution can therefore be used for refinement of the soil grid, a priori. Simulations show that the accuracy is indeed maintained for a priori refined grids but with reduced computational costs as compared to regular fine grids. Comparison with a well recognized a posteriori error estimate strengthen these results. Citation: Schröder, T., L. Tang, M. Javaux, J. Vanderborght, B. Körfgen, and H. Vereecken (2009), A grid refinement approach for a three-dimensional soil-root water transfer model, Water Resour. Res., 45, W10412,