The interaction of soil biota and soil structure under global change

Abstract

The structural framework of soil mediates all soil processes, at all relevant scales. The spatio‐temporal heterogeneity prevalent in most soils underpins the majority of biological diversity in soil, providing refuge sites for prey against predator, flow paths for biota to move, or be moved, and localized pools of substrate for biota to multiply. Just as importantly, soil biota play a crucial role in mediating soil structure: bacteria and fungi aggregate and stabilize structure at small scales (μm–cm) and earthworms and termites stabilize and create larger‐scale structures (mm–m). The stability of this two‐way interaction of structure and biota relations is crucial to the sustainability of the ecosystem. Soil is constantly reacting to changes in microclimates, and many of the soil–plant–microbe processes rely on the functioning of subtle chemical and physical gradients. The effect of global change on soil structure–biota interactions may be significant, through alterations in precipitation, temperature events, or land‐use. Nonetheless, because of the complexity and the ubiquitous heterogeneity of these interactions, it is difficult to extrapolate from general qualitative predictions of the effects of perturbations to specific reactions. This paper reviews some of the main soil structure–biota interactions, particularly focusing on soil stability, and the role of biota mediating soil structures. The effect of alterations in climate and land‐use on these interactions is investigated. Several case studies of the effect of land‐use change are presented.

Transient dwarfism of soil fauna during the Paleocene–Eocene Thermal Maximum

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Plant: soil interactions in temperate multi-cropping production systems

“…EPS), which can affect soil binding and adhesion (soil aggregation) directly or indirectly via microbial activity; and water uptake, which affects slaking (Materechera et al 1994;Angers and Caron 1998;Pierret et al 2011). Such processes result in general packing effects around the roots (Clemente et al 2005), which are involved in the formation of macropores (Young et al 1998), especially when deeprooted species are grown. Multiple-crop systems can incorporate a range of differing root networks and structures, generally increasing depths and overall rootlength densities, compared to sole crops.…”

Improvement, calibration and validation of a distributed hydrological model over France

“…In ISBA, k sat depends only on soil texture (through the empirical equations of Clapp and Hornberger, 1978). As texture is constant with depth, ISBA does not consider the changes in hydraulic conductivity produced by structural causes, for example, the presence of macropores (which are produced by such agents as plant roots, soil cracks, or soil fauna Young et al, 1998). Therefore, the lack of representation of the structure of the soil, leads to a k sat that does not depend on depth and, therefore, to a non adequate C 3 .…”