Quantification of soil structural changes induced by cereal anchorage failure: Image analysis of thin sections

Abstract

Cereal anchorage failure, or lodging, is the permanent displacement of a crop from the vertical and results in significant annual yield losses globally. Several factors have been identified as contributors to this phenomenon but the precise mechanisms of failure are still largely unknown because of difficulties in observing these processes as they occur in situ. To identify potential soil management practices to minimize losses associated with cereal root failure, an understanding of the nature of root-soil interactions attributed to lodging is needed. An experiment was conducted that involved field impregnation and subsequent thin sectioning of lodged and unlodged root-soil complexes from contrasting soils, cereal crops, and management practices to elucidate the effects of lodging on soil structure and porous architecture. Using image analysis, size and distribution of pores in soils were quantified at both meso-(100-30 lm) and microscales (<30 lm). A significant effect of lodging on porosity was recorded whereby lodging reduced total porosity through compaction created by movement of the stem base, although this was variable among soil types. Pore-size distributions comprehensively supported these trends since alteration in the relative frequency of pores within specific size classes was clearly observed. The effects of lodging were more pronounced at the mesoscale because the data were more susceptible to variations created by natural soil heterogeneity at the microscale. These data suggested that sideways movement of the subterranean stem within the soil is a significant factor which is likely to affect the propensity for a cereal plant to lodge, indicating soil strength in the upper part of the soil profile is crucial.

Intra‐aggregate Pore Characteristics: X‐ray Computed Microtomography Analysis

“…This is a significant step in characterizing heterogeneity of soil environments at micro-scales, as it allows obtaining more precise information regarding the physical structure of the soil aggregate matrix in three dimensions (3D). Solid-pore structures of intact soil matrix have been characterized by extracting fractal dimensions or multifractal spectra (e.g., Dathe and Thullner, 2005;Dathe et al, 2006;Gibson et al, 2006) and by conducting morphological characterization of soil macropore networks (Pierret et al, 1999(Pierret et al, , 2002De Gryze et al, 2004;Mooney et al, 2006Mooney et al, , 2007Mooney and Morris, 2008;Peth et al, 2008;Udawatta et al, 2008). Nunan et al (2006) applied geostatistical tools to quantify pore geometry for soil aggregates 1 to 3 mm in size at a scanning resolution of 4.4 [im.…”

Micromorphological analysis of soil structure under no tillage management in the black soil zone of Northeast China

“…Pore space was extracted mainly according to Mooney et al (2007). But in order to overcome the overestimate of pore space caused by transparent minerals, the CPL images taken at 0° and 45° directions of same field of view were used in this study.…”

Developing X-ray Computed Tomography to non-invasively image 3-D root systems architecture in soil

“…This voxel data can easily be separated into horizontal, planar slices, mimicking the physical slicing of soil cores e.g. Mooney et al (2007). If a given slice is displayed as a 2-D grey level image, the root system will appear as a set of (usually) elliptical regions.…”

“…Mooney et al (2007) successfully used soil thin sections to look at undisturbed root-soil interactions and explore the mechanisms of cereal root lodging. This technique is, however, limited to 2-D (unless many serial sections are taken) and extremely laborious as one thin section can take several weeks to prepare.…”