Backscattered Electron Scanning Images of Soil Porosity for Analyzing Soil Compaction around Roots

Bruand, Ary; Cousin, Isabelle; Nicoullaud, Bernard; Duval, Odile; Begon, J.C.

doi:10.2136/sssaj1996.03615995006000030031x

Cited by 146 publications

(78 citation statements)

References 12 publications

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“…This may be due to the presence of clay coatings that limited the interaction between the matrix pores and pore domain originated by roots and soil organisms. Another reason for flow limitation between the two pore domains may be the soil densification around the roots that was described by Bruand et al (1996). The impact of a proper description of the multimodal flow domain on water and herbicide transport was shown by Kodešová et al (2005).…”

Section: Discussionmentioning

confidence: 99%

Impact of plant roots and soil organisms on soil micromorphology and hydraulic properties

et al. 2006

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A soil micromorphological study was performed to demonstrate the impact of soil organisms on soil pore structure. Two examples are shown here. First, the influence of earthworms, enchytraeids and moles on the pore structure of a Greyic Phaeozem is demonstrated by comparing two soil samples taken from the same depth of the soil profile that either were affected or not affected by these organisms. The detected image porosity of the organism-affected soil sample was 5 times larger then the porosity of the not-affected sample. The second example shows macropores created by roots and soil microorganisms in a Haplic Luvisol and subsequently affected by clay coatings. Their presence was reflected in the soil water retention curve, which displayed multiple S-shaped features as obtained from the water balance carried out for the multi-step outflow experiment. The dual permeability models implemented in HYDRUS-1D was applied to obtain parameters characterizing multimodal soil hydraulic properties using the numerical inversion of the multi-step outflow experiment.

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Section: Discussionmentioning

confidence: 99%

Impact of plant roots and soil organisms on soil micromorphology and hydraulic properties

et al. 2006

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“…Deformation of the rhizosphere will be greatest where roots have historically exerted most mechanical stress on the surrounding soil. Such deformations can be large and estimates of local density around maize roots indicate dry bulk densities as great as 1.8 g cm −3 next to the root surface, as compared with 1.54 g cm −3 in the bulk soil (Bruand et al 1996;Young 1998). The variation in soil porosity has been modelled as decreasing exponentially away from the root surface (Dexter 1987), although this form of model is derived mainly from empirical fits to the data available, rather than to a mechanically based model.…”

Section: Ecological Consequences Of Rhizosphere Strengthmentioning

confidence: 99%

Rhizosphere: biophysics, biogeochemistry and ecological relevance

Bengough²,

et al. 2009

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Life on Earth is sustained by a small volume of soil surrounding roots, called the rhizosphere. The soil is where most of the biodiversity on Earth exists, and the rhizosphere probably represents the most dynamic habitat on Earth; and certainly is the most important zone in terms of defining the quality and quantity of the Human terrestrial food resource. Despite its central importance to all life, we know very little about rhizosphere functioning, and have an extraordinary ignorance about how best we can manipulate it to our advantage. A major issue in research on rhizosphere processes is the intimate connection between the biology, physics and chemistry of the system which exhibits astonishing spatial and temporal heterogeneities. This review considers the unique biophysical and biogeochemical properties of the rhizosphere and draws some connections between them. Particular emphasis is put on how underlying processes affect rhizosphere ecology, to generate highly heterogeneous microenvironments. Rhizosphere ecology is driven by a combination of the physical architecture of the soil matrix, coupled with the spatial and temporal distribution of rhizodeposits, protons, gases, and the role of roots as sinks for water and nutrients. Consequences for plant growth and whole-system ecology are considered. The first sections address the physical architecture and soil strength of the rhizosphere, drawing their relationship with key functions such as the movement and storage of elements and water as well as the ability of roots to explore the soil and the definition of diverse habitats for soil microorganisms. The distribution of water and its accessibility in the rhizosphere is considered in detail, with a special emphasis on spatial and temporal dynamics and heterogeneities. The physical architecture and water content play a key role in determining the biogeochemical ambience of the rhizosphere, via their effect on partial pressures of O 2 and CO 2 , and thereby on redox potential and pH of the rhizosphere, respectively. We address the Plant Soil

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“…Because of larger diameters of roots than soil pores, roots can also increase the bulk density of the soil near the roots during the root penetration (Dexter 1987) and this phenomenon can change the physical, biological, and chemical aspects of the soil near the roots (Glinski and Lipiec 1990). Change in micro-and mesoporosity around roots can also be quantified by scanning electron microscopy (Bruand et al 1996). Fig.…”

Section: Rootsmentioning

confidence: 99%