We need to understand the underlying dynamics of the soil system if we are to exploit the ecosystem services it provides in a sustainable way. We already know that the physical, chemical and biological components of the system are strongly interrelated and that the interactions between them are key internal drivers of change. Unfortunately, not enough is known about the details of these interactions to develop a unifying conceptual framework in which theoreticians and experimentalists can operate to understand the consequences for the dynamics of the soil system. To some extent this has been frustrated by the division of soil science into separate disciplines that has been driven by the desire to simplify seemingly overwhelming complexity. However, recent progress is beginning to reveal important features of a unifying framework, and in particular that the complexity of the system should be embraced as an essential characteristic rather than designed out. Not only might this complexity provide clues to help identify the underlying dynamical processes, but it may also be the only basis for deciding the nature of the data and logical endpoint to the level of detail required from the different disciplines in soil science to inform issues of sustainability. 

This lecture will explore these ideas and will present the challenges facing us. The importance of increased understanding of pore-scale processes in soil for developing an integrated picture of its larger-scale emergent behaviour will be argued. Modelling will play a crucial role in incorporating the required complexities and new opportunities will be presented. The challenge of non-destructively measuring the spatio-temporal behaviour of soil will be outlined and a range of techniques discussed. Finally, we will provide working examples of what an integrated pore-scale model for soil might look like.