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Research article2019Peer reviewedOpen access

Quantification of the structure evolution in a garden soil over the course of two years

Koestel, John; Schlueter, Steffen

Abstract

In this proof-of-concept, we demonstrate the potential of quantifying the structural evolution in an individual soil sample with the help of X-ray imaging. The soil sample was acquired in summer 2013 after a manual seedbed preparation and scanned with X-ray CT on six occasions during the following two years. After each imaging session, the soil sample was re-installed into the field. We focused on analyzing the evolution of soil morphologic measures that are thought to be fundamental to air and water flow in soil. We also quantified deformation of the soil matrix during the experiment. Our results illustrate the effects of several biotic and abiotic processes on the evolution of soil structure. A well-connected inter-aggregate pore network after seedbed preparation was replaced by a sparser network of larger biopores. Macro-faunal burrowing activity generally increased morphological measures associated with larger air and hydraulic conductivity as well as a better aeration. Soil settling and the growth of a dandelion tap-root acted in the opposite direction. Soil settling and compaction continued during the entire experimental period, but was restricted to soil depths below 20 mm. Other noteworthy observations that appear worth investigating in follow-up experiments were i.) the strong variation in the critical pore diameter, which could explain the commonly noted large temporal variability of saturated hydraulic conductivity, ii) the much greater extent of lateral compaction due to tap root growth than macro-faunal burrowing, and iii.) the short life-span of large biopores. We conclude that the approach presented here shows great potential for quantifying soil structural dynamics pertaining to individual structure-forming and degrading processes under field conditions. This kind of data could also prove very useful for constructing and testing 'next-generation' models that link a dynamic description of soil structure to various processes and functions in the soil-plant system.

Published in

Geoderma
2019, Volume: 338, pages: 597-609 Publisher: ELSEVIER SCIENCE BV

    UKÄ Subject classification

    Soil Science

    Publication identifier

    DOI: https://doi.org/10.1016/j.geoderma.2018.12.030

    Permanent link to this page (URI)

    https://res.slu.se/id/publ/98451