Down to the root of vegetated soil: challenges and the state-of-the-art

Vegetated soil plays an essential role in confronting climate change. Soil, together with its ecosystem, stores vast amounts of carbon; it is also the construction material most widely used for the built environment. The expected impacts of climate change, such as extreme wetting-drying cycles, pose an urgent need to understand the interplay between soil deformation, root growth, and water/solute uptake. The key to this challenge lies in the extension of unsaturated soil mechanics to incorporate bio-hydrological processes, such as root growth and water uptake. In this paper, we first provide an overview of the state-of-the-art knowledge of root-zone mechanics and bio-hydrology. We identify the main knowledge gaps and suggest an integrated, bottom-to-top approach to develop a multidisciplinary understanding of soil-water-root interaction. We explain how emerging experimental and numerical methods can be used to study rooted soil under wetting-drying cycles. We focus on the biophysical processes at the scale of plant roots, soil particles and their interfaces, and discuss potential up-scaling to the continuum/field scale. An outlook on possible further research involves effects of temperature and microbial activities.

Automated summary

Vegetated soil, as a storage of carbon and widely used construction material, plays a crucial role in tackling climate change. Understanding the interaction between soil deformation, root growth, and water/solute uptake is urgently needed due to the expected impacts of climate change. This paper provides an overview of the latest knowledge in root-zone mechanics and bio-hydrology, identifies knowledge gaps, and proposes an integrated approach to study soil-water-root interaction.