Understanding the joint impacts of soil architecture and microbial dynamics on soil functions: Insights derived from microscale models

Abstract

Over the last decades, a new generation of microscale models has been developed to simulate soil microbial activity. An earlier article (Pot et al., 2021) presented a detailed review of the description of soil architecture and microbial dynamics in these models. In the present article, we summarise the main results obtained by these models according to six model outputs: growth and spatial organisation of microbial colonies, soil hydraulic conductivity, coexistence and trophic interactions of microorganisms, temporal dynamics of the amount of solid and dissolved organic matter in soil and, microbial production of CO 2 . For each of these outputs, we draw particular attention to the respective roles of soil architecture and microbial dynamics, and we report how microscale models allow for disentangling and quantifying them. We finally discuss limitations and future directions of microscale models in combination with the on-going development of highperformance imaging tools revealing the spatial heterogeneity of the actors of soil microbial activity. Highlights• We review the insights on soil functions derived from microscale models of soil microbial processes.• Microscale models disentangle the complex interactions between soil architecture and microbial dynamics.• Spatial accessibility of resources to microbes, growth and ecological interactions are key factors in soil functions.• Translation of knowledge of interactions at the microscopic scale into larger scales is still in its infancy.

Perspectives from the Fritz‐Scheffer Awardee 2021: Soil organic matter storage and functions determined by patchy and piled‐up arrangements at the microscale

“…This imposes various physicochemical constraints on soil microbes. These constraints are determined by a restricted encounter of resources and microbial consumption, which depends on the allocation of microbes across compartmentalized units (Kleber et al, 2021;Pot et al, 2022).…”

Herbivore assemblages affect soil microbial communities by altering root biomass and available nutrients in an alpine meadow

“…These results indicate that the difference in bacterial b-diversity was due to the dominant species, whereas in fungi was due to rare species. Theoretically, different plant characteristics and soil environments can create different niches (Hamid et al, 2021), and, consequently, affect specific soil microbial communities (Pot et al, 2022). In the current study, bacterial b-diversity was driven mainly by plant a-diversity and root biomass, but fungal b-diversity was driven mainly by AK and SBD.…”

Storage of soil carbon is not sequestration: Straightforward graphical visualization of their basic differences

“…Thankfully, significant technological advances over the last two decades, in particular in terms of imaging technologies and spectroscopic methods (e.g., Bacq-Labreuil et al, 2018;Baveye et al, 2018;Powlson & Neal, 2021) make it possible to supplement traditional bulk (macroscopic) measurements of soil parameters with a number of microscale characterizations of the environments in which microorganisms reside in the pore space. These insights are increasingly reflected by a new generation of mathematical models that take the microscale heterogeneity of soils explicitly into account when describing the fate of organic matter (e.g., Falconer et al, 2015;Golparvar et al, 2021;König et al, 2020;Pot et al, 2022aPot et al, , 2022bVogel et al, 2015). One can hope that, as this research amplifies in the coming years, we shall get to understand far better than we do at the moment not only what happens to crop residues incorporated into soils-a question farmers and regulatory agencies will undoubtedly keep asking in the foreseeable future-but also how this practice can help soils become rapidly more resilient to fast-progressing environmental changes (as discussed in Baveye et al, 2020).…”