Combining new techniques to investigate water dynamics above a shallow restrictive layer.

2021 ◽  
Author(s):  
Giorgio Capello ◽  
Marcella Biddoccu ◽  
Simone Di Prima ◽  
Laurent Lassabatere
Keyword(s):  
Root System ◽  
Measurement Techniques ◽  
Penetration Resistance ◽  
Water Dynamics ◽  
Dense Layer ◽  
Soil Core ◽  
Undisturbed Soil ◽  
Soil Matrix ◽  
Infiltration Test ◽  
Viscous Solution

<p>Adopting integrated measurement techniques may enhance our understanding of hydropedological processes within the critical zone. To investigate lateral subsurface flow due to lithological discontinuities, a ponding infiltration test, two GPR surveys, and soil penetration resistance (PR) measurements were conducted on a 1 m<sup>2</sup> plot in a vegetated area located in the university campus of Doua (Lyon, France). A GPR grid with 0.2 m intervals was established. In the center of the grid, around the root system of a hawthorn shrub, an infiltration test was conducted using an automated single-ring infiltrometer proposed by Concialdi et al. (2020), to infiltrate a shear-thinning viscous solution (1 g L<sup>−1</sup> Xanthan gum powder). The viscous solution was expected to fill preferential pathways due to the roots, with limited infiltration into the soil matrix, and thus reveal complex geometries or macropore networks in highly heterogeneous soils. To create three-dimensional (3D) representations of the infiltrated solution, two GPR surveys were carried out just before and 20 min after the infiltration test, using a GSSI (Geophysical Survey System Inc., Salem, NH) SIR 3000 system with a 900 MHz antenna. A total of 24 radargrams were collected in time mode by moving the antenna along the survey lines and recording the markers position along the survey line intersections. After the second GPR survey, PR was measured at each of the 36 intersection points of the grid using an electronic hand-pushed cone penetrometer. The cone had a 30° angle and a base area of 1 cm<sup>2</sup>, inserted into the soil at a constant speed of 2 cm s<sup>−1</sup> to a depth of 0.8 m. These measurements were aimed to highlight contrasting penetration resistance characteristics between different soil horizons. We also determined the soil bulk density from 24 undisturbed soil cores (~ 100 cm<sup>3</sup>) collected at different depths from 0 to 50 cm. Finally, an auger was used to extract a 0.69-m-depth soil core for the direct observation of lithological heterogeneities.</p><p>Differenced radargrams from pre- and post-infiltration surveys allowed to detect the 3D infiltration bulb, which was vertically elongated and irregularly shaped, but with an evident horizontal divergence between the depth of 20 and 30 cm. Below 30 cm depth, a significant increasing of soil PR and BD (respectively higher than 2.5 MPa and 1.50 g cm<sup>-3</sup>, between 30 and 50 cm depth) was detected, indicating the presence of a underlying layer, which was also identifiable by visual observation of the soil core. This dense layer impeded water flow. Consequently, the liquid solution partially diverged laterally and accumulated upside this layer, and partially infiltrated into the dense layer along preferential flow paths in correspondence with the plant root system, as detected by the 3D GPR diagram. Summing up and considering every aspect, this study allowed to identify water perching above a shallow restrictive layer for a better understanding of the water dynamics of the investigated soil. This study shows the benefits to couple different types of soil physics approaches to relate hydrological processes to the soil hydraulic and mechanical properties.</p>

scholarly journals Alternative method for volumetric core removal in hardsetting soils

2005 ◽  
Vol 62 (5) ◽  
pp. 493-497 ◽  
Author(s):  
Herdjania Veras de Lima ◽  
Álvaro Pires da Silva ◽  
Sílvia Imhoff ◽  
Afrânio Ferreira Neves Junior
Keyword(s):  
Soil Bulk Density ◽  
Field Method ◽  
Laboratory Method ◽  
Soil Samples ◽  
Soil Core ◽  
Hydraulic Pump ◽  
Undisturbed Soil ◽  
Alternative Method ◽  
Moisture Conditions ◽  
Large Soil

Due to the narrow window of ideal moisture conditions required for collecting undisturbed soil samples from hardsetting horizons in the field, this study compared the efficiency of an alternative method of soil core removal in the laboratory with that of the traditional field method by using measurements of soil bulk density data (Db). In a first sampling, cylinders were removed with a soil sampler in the field. In a second sampling, large soil blocks were removed with Kubiena-type zinc (brass) boxes in the field. Volumetric core cylinder samples were removed from these blocks in the laboratory with a manual hydraulic pump. There were no differences between the Db values determined from the laboratory and the field coring method. The laboratory method was considered more efficient than the field method because it allowed reductions in the errors made by operators in the field, and those caused by differences in soil water content. The laboratory method allows sampling in hardsetting horizons throughout the year, and collecting soil core samples under conditions of controlled moisture and applied force.

Biophysical interactions at the root–soil interface: a review

1998 ◽  
Vol 130 (1) ◽  
pp. 1-7 ◽  
Author(s):  
I. M. YOUNG
Keyword(s):  
Crop Yields ◽  
Farming Systems ◽  
Root Surface ◽  
Biological Properties ◽  
Water Dynamics ◽  
Limited Attention ◽  
Small Scale ◽  
Soil Matrix ◽  
Increased Risk ◽  
Soil Interface

Soil close to roots generally has chemical, physical and biological properties which are significantly different from those of soil located some distance away (Jenny & Grossenbacher 1963; Hawes & Pueppke 1986; Young 1995). The root–soil interface is defined as soil near to or adhered to the root surface to some small distance into the soil matrix. This distance may vary between <1 mm and c. 10 mm. Working definitions include rhizosphere, where ‘zones of influence’ are inferred, and rhizosheath, when soil adhered to the root is discussed. Most work carried out at the root–soil interface has concentrated on biological or chemical processes, due both to the fact that the relevant techniques required to examine these processes have been more advanced than the physical techniques, and also because the farmer is generally offered either biological or chemical solutions to his everyday problems, as these are readily accessible, easy to use and cheap. The main manipulation of soil physical conditions occurs during cultivations, and the addition or removal of water from the soil profile. Intensive cultivations are a regular occurrence in many farming systems, despite the potential drawbacks: damage of the soil structure, leading to reduced crop yields and an increased risk of erosion.The main aim of this review is not to cover all the complex issues related to the root–soil interface. Instead, it concentrates on the biophysical processes which, compared with conventional plant physiological and soil microbiological research, have attracted relatively limited attention (e.g. see Waisel et al. 1996). The review examines small-scale (μm-mm) interactions and, where possible, links their impact to the larger scale. Three interacting areas are investigated: the physical structure of the soil and root growth, water dynamics and microbial dynamics.

Dual permeability soil water dynamics and water uptake by roots in irrigated potato fields

Biologia ◽  
2007 ◽  
Vol 62 (5) ◽  
Author(s):  
František Doležal ◽  
David Zumr ◽  
Josef Vacek ◽  
Josef Zavadil ◽  
Adriano Battilani ◽  
...  
Keyword(s):  
Soil Water ◽  
Field Experiments ◽  
Preferential Flow ◽  
Water Movement ◽  
Root Zone ◽  
Water Pressure ◽  
Boundary Curve ◽  
Water Dynamics ◽  
Permeability Model ◽  
Soil Matrix

AbstractWater movement and uptake by roots in a drip-irrigated potato field was studied by combining field experiments, outputs of numerical simulations and summary results of an EU project (www.fertorganic.org). Detailed measurements of soil suction and weather conditions in the Bohemo-Moravian highland made it possible to derive improved estimates of some parameters for the dual permeability model S1D_DUAL. A reasonably good agreement between the measured and the estimated soil hydraulic properties was obtained. The measured root zone depths were near to those obtained by inverse simulation with S1D _DUAL and to a boundary curve approximation. The measured and S1D _DUAL-simulated soil water pressure heads were comparable with those achieved by simulations with the Daisy model. During dry spells, the measured pressure heads tended to be higher than the simulated ones. In general, the former oscillated between the simulated values for soil matrix and those for the preferential flow (PF) domain. Irrigation facilitated deep seepage after rain events. We conclude that several parallel soil moisture sensors are needed for adequate irrigation control. The sensors cannot detect the time when the irrigation should be stopped.

scholarly journals Digital, Three-Dimensional Visualization of Root Systems in Peat

Soil Systems ◽  
2020 ◽  
Vol 4 (1) ◽  
pp. 13 ◽  
Author(s):  
Stella Gribbe ◽  
Gesche Blume-Werry ◽  
John Couwenberg
Keyword(s):  
Root System ◽  
3D Visualization ◽  
Large Diameter ◽  
3D Structure ◽  
Three Dimensional ◽  
Plant Morphology ◽  
Dimensional Structure ◽  
Valuable Insight ◽  
Similar Data ◽  
Soil Matrix

Belowground plant structures are inherently difficult to observe in the field. Sedge peat that mainly consists of partly decayed roots and rhizomes offers a particularly challenging soil matrix to study (live) plant roots. To obtain information on belowground plant morphology, research commonly relies on rhizotrons, excavations, or computerized tomography scans (CT). However, all of these methods have certain limitations. For example, CT scans of peat cores cannot sharply distinguish between plant material and water, and rhizotrons do not provide a 3D structure of the root system. Here, we developed a low-cost approach for 3D visualization of the root system in peat monoliths. Two large diameter (20 cm) peat cores were extracted, frozen and two smaller peat monoliths (47 × 6.5 × 13 cm) were taken from each core. Slices of 0.5 mm or 1 mm were cut from one of the frozen monoliths, respectively, using a paper block cutter and the freshly cut surface of the monolith was photographed after each cut. A 3D model of the fresh (live) roots and rhizomes was reconstructed from the resulting images of the thinner slices based on computerized image analysis, including preprocessing, filtering, segmentation and 3D visualization using the open-source software Fiji, Drishti, and Ilastik. Digital volume measurements on the models produced similar data as manual washing out of roots from the adjacent peat monoliths. The constructed 3D models provide valuable insight into the three-dimensional structure of the root system in the peat matrix.

How representative is the conventional undisturbed soil core sample in terms of fllow properties?

2020 ◽  
Author(s):  
Kirill Gerke ◽  
Marina Karsanina
Keyword(s):  
Hydraulic Conductivity ◽  
Boundary Conditions ◽  
Image Fusion ◽  
Correlation Functions ◽  
Physical Review ◽  
Soil Samples ◽  
Soil Core ◽  
Pore Scale ◽  
Undisturbed Soil ◽  
Multi Scale

&lt;p&gt;Classic soil physics relies heavily on the concept of representative elementary volume (REV), which is necessary to perform upscaling from the studied soil samples and parameterize continuum scale hydrological models (e.g., based on Richards equation). In this paper we explore the boundaries of the classic REV concept and conventional representativity studies that claim REV for a given physical property if its values converge to a steady value with increasing sample&amp;#8217;s volume. We chose two conventional undisturbed soil samples from Ah and B horizons and performed pore-scale flow simulations based on their X-ray microtomography scans. The volumes of the simulation domains were 729 million of voxels with a physical volume within the order of magnitude of the whole soil core. Based on 3D pore geometry images and resulting flow velocity and pressure fields we performed REV analysis for saturated hydraulic conductivity and porosity. To further facilitate the REV analysis, we also evaluated the stationarity of pore structures by computing directional correlation functions for studied images. We concluded that neither of the studied samples can be considered to be representative due to its structural non-stationarity, which reflects on the behavior of Ksat values within the subcubes of different volume within the samples. In this contribution we extensively discuss the implications of such results. While it was possible to show that studied soil samples are not REVs for saturated hydraulic conductivity, we were unable to establish any relevant domain length scale. The latter may require tensorial flow property analysis with correct boundary conditions (Gerke et al., 2019), multi-scale soil structure imaging (Gerke et al., 2015; Karsanina et al., 2018; Karsanina and Gerke, 2018) and pore-scale simulations on fused multi-scale images (Miao et al., 2017; Gerke et al., 2018).&lt;/p&gt;&lt;p&gt;This work was supported by Russian Foundation for Basic Research grant 20-54-12030 &amp;#1053;&amp;#1053;&amp;#1048;&amp;#1054;_&amp;#1072; and 18-34-20131 &amp;#1084;&amp;#1086;&amp;#1083;_&amp;#1072;_&amp;#1074;&amp;#1077;&amp;#1076;.&lt;/p&gt;&lt;p&gt;References:&lt;/p&gt;&lt;p&gt;Karsanina, M. V., Gerke, K. M., Skvortsova, E. B., Ivanov, A. L., &amp; Mallants, D. (2018). Enhancing image resolution of soils by stochastic multiscale image fusion. Geoderma, 314, 138-145.&lt;/p&gt;&lt;p&gt;Gerke, K. M., Karsanina, M. V., &amp; Mallants, D. (2015). Universal stochastic multiscale image fusion: an example application for shale rock. Scientific reports, 5, 15880.&lt;/p&gt;&lt;p&gt;Gerke, K. M., Vasilyev, R. V., Khirevich, S., Collins, D., Karsanina, M. V., Sizonenko, T. O., Korost D.V., Lamontagne S., &amp; Mallants, D. (2018). Finite-difference method Stokes solver (FDMSS) for 3D pore geometries: Software development, validation and case studies. Computers &amp; Geosciences, 114, 41-58&lt;/p&gt;&lt;p&gt;Karsanina, M. V., &amp; Gerke, K. M. (2018). Hierarchical Optimization: Fast and Robust Multiscale Stochastic Reconstructions with Rescaled Correlation Functions. Physical Review Letters, 121(26), 265501.&lt;/p&gt;&lt;p&gt;Miao, X., Gerke, K. M., &amp; Sizonenko, T. O. (2017). A new way to parameterize hydraulic conductances of pore elements: A step towards creating pore-networks without pore shape simplifications. Advances in Water Resources, 105, 162-172.&lt;/p&gt;&lt;p&gt;Gerke, K. M., Karsanina, M. V., &amp; Katsman, R. (2019). Calculation of tensorial flow properties on pore level: Exploring the influence of boundary conditions on the permeability of three-dimensional stochastic reconstructions. Physical Review E, 100(5), 053312.&lt;/p&gt;

Undisturbed soil-core sampler for submerged puddled soils

1991 ◽  
Vol 4 (3) ◽  
pp. 315-317
Author(s):  
P.K. Sharma ◽  
R.M. Bhagat
Keyword(s):  
Soil Core ◽  
Undisturbed Soil ◽  
Core Sampler

High soil penetration resistance reduces sugarcane root system development

2011 ◽  
Vol 117 ◽  
pp. 201-210 ◽  
Author(s):  
R. Otto ◽  
A.P. Silva ◽  
H.C.J. Franco ◽  
E.C.A. Oliveira ◽  
P.C.O. Trivelin
Keyword(s):  
Root System ◽  
System Development ◽  
Penetration Resistance ◽  
Root System Development ◽  
Soil Penetration Resistance ◽  
High Soil

Carbon mineralisation and pore size classes in undisturbed soil cores

Soil Research ◽  
2013 ◽  
Vol 51 (1) ◽  
pp. 14 ◽  
Author(s):  
Liesbeth Bouckaert ◽  
Steven Sleutel ◽  
Denis Van Loo ◽  
Loes Brabant ◽  
Veerle Cnudde ◽  
...  
Keyword(s):  
Organic Matter ◽  
Pore Network ◽  
Order Kinetic ◽  
Soil Cores ◽  
Undisturbed Soil ◽  
Soil Matrix ◽  
X Ray ◽  
C Mineralisation ◽  
The Impact ◽  
Undisturbed Soil Cores

Soil pore network effects on organic matter turnover have, until now, been studied indirectly because of lack of data on the 3D structure of the pore network. Application of X-ray computed tomography (X-ray CT) to quantify the distribution of pore neck size and related pore sizes from undisturbed soil cores, with simultaneous assessment of carbon (C) mineralisation, could establish a relationship between soil organic matter (SOM) decomposition and soil pore volumes. Eighteen miniature soil cores (diameter 1.2 cm, height 1.2 cm) covering a range of bulk densities were incubated at 20°C for 35 days. Respiration was modelled with a parallel first- and zero-order kinetic model. The cores were scanned at 9.44 µm resolution using an X-ray CT scanner developed in-house. Correlation analysis between the slow pool C mineralisation rate, ks, and pore volume per pore neck class yielded significant (P < 0.05) positive correlations: r = 0.572, 0.598, and 0.516 for the 150–250, 250–350, and >350 µm pore neck classes, respectively. Because larger pores are most probably mainly air-filled, a positive relation with ks was ascribed to enhanced aeration of smaller pores surrounding large pores. The weak and insignificant relationship between the smallest pore neck class (<9.44 µm) and ks could be explained by obstructed microbial activity and mobility or diffusion of exo-enzymes and hydrolysis products as a result of limited oxygen availability. This study supports the hypothesis that the impact of soil structure on microbial processes occurs primarily via its determination of soil water distribution, which is possibly the main driver for the location of C mineralisation in the soil matrix.

Use of natural heterogeneity in a small field site to explore the influence of the soil matrix on nitrogen mineralisation and nitrification

Soil Research ◽  
1997 ◽  
Vol 35 (3) ◽  
pp. 579 ◽  
Author(s):  
D. T. Strong ◽  
P. W. G. Sale ◽  
K. R. Helyar
Keyword(s):  
Soil Properties ◽  
Multiple Regression ◽  
Multiple Regression Equation ◽  
Regression Equations ◽  
Small Field ◽  
Undisturbed Soil ◽  
Soil Matrix ◽  
Ph Buffering ◽  
Functional Relationships ◽  
Physical Scale

The influence of soil properties on microbiological processes is often examined by comparing the behaviour of taxonomically disparate soils. One of the limitations of this approach is that the results can be confounded by the unmeasured properties which vary between soils of different type or between soils which have had different climatic and management histories. This study tested the hypothesis that the heterogeneity between 100 small contiguous undisturbed soil cubes (about 1·7 cm3), sampled from the surface of a very small field plot (14 by 14 cm), was sufficiently large to use for the exploration of how soil properties influence biological processes. After incubation of the soil for 35 days, the coefficients of variation for nitrate (NO3), ammonium (NH4), gravimetric water content (θg), bulk density (BD), pH buffering capacity (pHBC), and pH were 28, 39, 27, 10, 13, and 2%, respectively. A multiple regression equation predicting nitrate concentration had an r2 value of 0·89 and significantly included 4 predictor variables, with only pH being non-significant. These analyses confirmed the hypothesis. When the values of measured soil properties of adjoining soil cubes were meaned to estimate values for larger soil volumes, the multiple regression equations for predicting NO3 concentration explained more of the variation (r2 values as high as 0·99). However, information concerning the influence of certain soil properties on N mineralisation and nitrification was lost, with only pHBC and BD remaining significant in the regression model. It was concluded that at a given physical scale of investigation, the structure of the spatial variability may determine whether or not a relationship between 2 variables is observed. Smaller samples are more likely to identify functional relationships which may exist between measured variables at the microscale.

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