Soil is a highly diverse ecosystem which supports a plethora of intertwined biophysical and biochemical processes. Soil structure is a determinant of soil biodiversity as it provides habitat for soil biological activity and permits the transport of essential resources. On the other hand, soil biological activity maintainins essential soil functions through the formation and preservation of soil structure and fertility.

In this paper, we focus on root-soil interactions and associated processes. A wide and complex range of specific physico-chemical processes occur in the vicinity of roots, an environment known as the rhizosphere. Through elongation, radial growth, and the diverse exchanges they have with their immediate environment (i.e. water and mineral nutrient absorption, respiration and other gas exchanges, exudation of chemical compounds - mineral ions and organic compounds -), roots modify soil physico-chemical conditions, at least locally. In parallel, as they develop, roots are exposed to highly heterogeneous soil conditions, both in space and time, which affect root functioning. Based on our results and the literature record, we first discuss the complexity and heterogeneity of soil ecosystems as examplified by the interactions between root distributions – soil structure – soil chemical properties and soil microbial activity. Despite the conspicuous prevalence of such interactions, knowledge on soil ecosystems is still mostly gained through research in the fields of soil biology, soil chemistry, soil physics and plant physiology, operating as independent disciplines.

In this context, we then examine how unifying modelling approaches of root-soil interactions and processes can help better integrate existing knowledge and make more decisive progress with our understanding of soil ecosystems. Specifically, we show how so-called 'root architectural models' can be used to investigate soil and plant processes involved in uptake processes at the scale of the whole root system while taking explicit account of individual roots and of local soil-root interactions.