Modelling water dynamics in the rhizosphere

We review the recent progress in the use of image based modelling to describe water dynamics in the rhizosphere. In addition, we describe traditional modelling and experimental methods, and how images obtained from X-ray Computed Tomography can be used in combination with direct pore-scale modelling to answer questions on water movement in the rhizosphere. The focus of this review is on the need for micro-scale experiments to parameterize image-based modelling on the pore-scale, and to show how variations in these parameters can lead to different macroscopic parameters when considering the movement of water on the plant scale. We finish the review with an illustrative example which highlights the importance of fluid-to-fluid contact angle, and the need for care in image preparation when using detailed models of this type.