Field methods to study the spatial root density distribution of individual plants

Robust Estimation of Absorbing Root Surface Distributions From Xylem Water Isotope Compositions With an Inverse Plant Hydraulic Model

“…Unfortunately, data on root distributions in general-and on A R in specific-is scarce, and little is known about the intraand interspecific variability in A R across different environments (Böhm, 2012). This paucity is caused in part by the available techniques to study root distributions of individual plants, which are often destructive, expensive, and labor intensive (Cabal et al, 2021). Root excavation, for example, holds the highest promise of most accurately characterizing a plant's natural root distribution (Böhm, 2012).…”

“…As an illustration, Preston (1942) estimated that one laborer requires approximately 5 weeks to fully excavate and examine the root system of single 15-year-old lodgepole pine. These time and labor disadvantages have led to the development of many other direct and indirect in situ techniques, such as rhizotron systems, acoustic and electromagnetic tomography, the auger method, or the use of non-radioactive tracers (reviewed in Cabal et al, 2021). However, while these techniques provide a less invasive alternative to root excavation, they generally fall short in the level of details they can provide on the distribution of the individual absorbing root surfaces.…”

Electrical Capacitance versus Minirhizotron Technique: A Study of Root Dynamics in Wheat–Pea Intercrops

“…Nevertheless, some studies revealed the inconsistencies with Dalton's proposals, and questioned the feasibility of the C R method [7]. Dietrich et al [8,9] suggested a revised model, and explored that C R was dominated by the stem base between the plant electrode and the substrate surface (with a negligible contribution of the roots), and was correlated with a stem cross-sectional area.…”

“…However, MR represents only part of the root system, with limited resolution for the fine roots that are responsible for water uptake [22]. The main biases are attributed to the artificial MR tube surface and the poor soil-tube wall contact (including soil gaps), which may result in modified temperature conditions, altered water flow and decreased soil penetration resistance, potentially changing the observed root density and traits [7,23]. The critical points in the MR technique are the assessment of root physiological status (activity) by visual evaluation (e.g., color, shrinking, contour smoothing, blotting), and the differentiation between the roots of individual plants [21].…”

Editorial: Modulation of Growth and Development of Tree Roots in Forest Ecosystems

“…Much of this disparity is likely ascribable to the methodological difficulties of studying plant roots, the associated rhizosphere, and related traits (Freschet et al, 2021a ). During the past two decades, a focus on methodological advancements has rendered root investigations more feasible and more standardized in terms of quantitative approaches (Bao et al, 2018 ; Montagnoli et al, 2018 ; Atkinson et al, 2019 ; Chiatante et al, 2019 ; Cabal et al, 2021 ; Freschet et al, 2021b ). This has allowed and encouraged a greater number of scientists to examine the hidden half of plants, thereby helping to reduce this long-standing knowledge discrepancy (Ryan et al, 2016 ; Freschet et al, 2021b ).…”