A critical assessment of the role of measured hydraulic properties in the simulation of absorption, infiltration and redistribution of soil water

1988 ◽  
Vol 15 (1) ◽  
pp. 73-86 ◽  
Author(s):  
D.R. Scotter ◽  
B.E. Clothier ◽  
T.J. Sauer
Keyword(s):  
Soil Water ◽  
Hydraulic Properties ◽  
Critical Assessment

Eco-hydrology interactions between trees, soil and water in terrestrial and wetland areas: The effect of tree planting on water flow dynamics in Wairarapa Wetlands, New Zealand

2021 ◽  
Author(s):  
◽  
Tapuwa Marapara
Keyword(s):  
New Zealand ◽  
Hydraulic Properties ◽  
Forested Wetlands ◽  
High Water ◽  
Flood Mitigation ◽  
Forested Wetland ◽  
Soil Hydrology ◽  
Catchment Scale ◽  
Soil And Water

<p>During the last two decades there has been increasing interest in the role of forests and wetlands as flood mitigating tools due to growing concerns regarding the sustainability of many traditional engineering flood defences such as dykes, sea walls and dams. In forests, the role is facilitated by the interaction between trees, soil and water. Specifically trees reduce surface runoff and prevent flooding through increased evapotranspiration and canopy interception and enhance physical and hydraulic properties of soil that are critical for the absorption and retention of flood waters by the soil. It is increasingly realised that the answer to flood mitigation is not a blanket recommendation to “plant trees”. This is because the role of trees varies spatially and temporally as a function of climate, topography, rainfall properties, soil type and condition, catchment scale and geology, among others. For example, where trees are present in wetlands, particularly forested wetlands, the mechanisms by which trees interact with soil and water are similar to that in forests but because of a high water table, the impact of trees may be reduced. Therefore, the mere presence of forests and forested wetlands will not necessarily deliver flood risk management.  The purpose of this study was to explore the effectiveness of trees as flood mitigating tools under various bio-geo climatic factors in forests and forested wetland environments. Three forms of investigation were followed to fulfil this purpose.  A detailed literature review was carried out to assess the role of trees and forests as flood mitigation tools under changing climate, topography, species type, rainfall properties, soil type and condition, catchment scale and geology. A field experiment was carried out to collect data and analyse the effect of trees on soil physical and hydraulic properties that include bulk density, saturated hydraulic conductivity, soil organic carbon, soil moisture content, matric potential and soil moisture retention in a previously forested wetland undergoing restoration in New Zealand. A spatially explicit decision support tool, the Land Use Capability Indicator (LUCI) was then used to determine appropriate areas where intervention can be targeted to optimise the role of trees as flood mitigating tools in previously forested wetlands undergoing restoration.  The detailed review identified a major data gap in the role of trees under hydric conditions (high water table), along with uncertainties on their effectiveness in large catchments (>˜40 km²) and in extreme rainfall events. The field experiment provided the first set of soil hydrology data from an ephemeral wetland in New Zealand showing the benefits of newly established trees in improving hydraulic conductivity of soils. The soil hydrology data is a useful baseline for continuous monitoring of the forested wetlands undergoing restoration. The use of the Land Use Capability Indicator was its first application for the optimisation of flood mitigation in a forested wetland. Its suggested target areas are not necessarily conducive for survival of some tree species, although if suitable species are established, flood risk mitigation could be maximised. Further research on what native species are best for what conditions and in what combinations is recommended, to increase survival in the proposed target areas.</p>

scholarly journals A thermodynamic formulation of root water uptake

2016 ◽  
Vol 20 (8) ◽  
pp. 3441-3454 ◽  
Author(s):  
Anke Hildebrandt ◽  
Axel Kleidon ◽  
Marcel Bechmann
Keyword(s):  
Soil Water ◽  
Water Uptake ◽  
Water Distribution ◽  
Bound Water ◽  
Root Water Uptake ◽  
Flow Path ◽  
Thermodynamic Evaluation ◽  
Entire Flow ◽  
Soil Water Distribution

Abstract. By extracting bound water from the soil and lifting it to the canopy, root systems of vegetation perform work. Here we describe how root water uptake can be evaluated thermodynamically and demonstrate that this evaluation provides additional insights into the factors that impede root water uptake. We derive an expression that relates the energy export at the base of the root system to a sum of terms that reflect all fluxes and storage changes along the flow path in thermodynamic terms. We illustrate this thermodynamic formulation using an idealized setup of scenarios with a simple model. In these scenarios, we demonstrate why heterogeneity in soil water distribution and rooting properties affect the impediment of water flow even though the mean soil water content and rooting properties are the same across the scenarios. The effects of heterogeneity can clearly be identified in the thermodynamics of the system in terms of differences in dissipative losses and hydraulic energy, resulting in an earlier start of water limitation in the drying cycle. We conclude that this thermodynamic evaluation of root water uptake conveniently provides insights into the impediments of different processes along the entire flow path, which goes beyond resistances and also accounts for the role of heterogeneity in soil water distribution.

The role of tree stem proximity in the spatial variability of soil water repellency in a eucalypt plantation in coastal Portugal

Soil Research ◽  
2005 ◽  
Vol 43 (3) ◽  
pp. 251 ◽  
Author(s):  
J. J. Keizer ◽  
A. J. D. Ferreira ◽  
C. O. A. Coelho ◽  
S. H. Doerr ◽  
M. C. Malvar ◽  
...  
Keyword(s):  
Soil Water ◽  
Water Repellency ◽  
Soil Water Repellency ◽  
Individual Measurement ◽  
Hydrophobic Compounds ◽  
Ethanol Droplet ◽  
Central Portugal ◽  
Living Organisms ◽  
Tree Stem

Certain organic compounds derived from living organisms or their decaying parts are generally accepted to induce soil water repellency. Water repellency may therefore be expected to increase with proximity to organisms releasing hydrophobic compounds. This hypothesis is tested here for Eucalyptus globulus trees, since eucalypt species are frequently associated with elevated repellency levels. In a young, first-rotation plantation on coastal dune sands in central Portugal, repeat measurements of water repellency using the ‘Molarity of an Ethanol Droplet’ (MED) test were carried out in situ between April 2001 and May 2002. On 25 dates, repellency was measured at initially 2 and later 3 distances on 2 sides of 8–11 randomly selected trees. On 15 occasions, additional repellency measurements were performed within small grids aside 3 of the selected trees. The postulated decrease in topsoil water repellency with increased distance from eucalypt tree stems was found to apply on several individual measurement dates, as well as, more unexpectedly since repellency usually is a transient phenomenon, for the study period as a whole. The results confirm the general association of eucalypt trees with water repellency, and indicate that tree stem proximity is an important but not sufficient factor to explain repellency distribution in topsoil.

scholarly journals The Catch of the Hyperreal: Yossarian and the Ideological Vicissitudes of Hyperreality

Text Matters ◽  
2018 ◽  
pp. 386-410
Author(s):  
Abdolali Yazdizadeh
Keyword(s):  
Twentieth Century ◽  
Cultural Theory ◽  
Critical Assessment ◽  
Vantage Point ◽  
The Novel ◽  
Fictional World ◽  
American Life ◽  
Ideological Discourse ◽  
Catch 22

Hyperreality is a key term in Jean Baudrillard’s cultural theory, designating a phase in the development of image where it “masks the absence of a profound reality.” The ambiance of Joseph Heller’s Catch-22 (1961) closely corresponds to Baudrillard’s notion of the hyperreal as images persist to precede reality in the fictional world of the novel. Since for Baudrillard each order of simulacra produces a certain mode of ideological discourse that impacts the perception of reality, it is plausible that the characters of this fictional context should be ideologically impacted by the hyperreal discourse. From this vantage point it is possible to have a new critical assessment of Yossarian’s (protagonist) antiheroic stance and study the role of the “business of illusion,” whose ideological edifice is based on the discourse of the hyperreal, on his antiheroic stance and actions. By drawing on Baudrillard’s cultural theory this paper aims to read Heller’s novel as a postmodern allegory of rebellion against the hyperreality of the twentieth-century American life and trace its relevance to modern-day U.S.

scholarly journals Raja yoga within the system of religious-ethical philosophy Of M. V. Lodyzhensky

2020 ◽  
pp. 64-90
Author(s):  
Oleg Viktorovich Solopov
Keyword(s):  
Critical Review ◽  
Scientific Literature ◽  
Critical Assessment ◽  
Special Role ◽  
The Novel ◽  
Ethical Philosophy ◽  
Knowledge Ontology ◽  
Comprehensive Study

This article is dedicated to examination of the characteristics of the doctrine of Raja yoga in interpretation Of M. V. Lodyzhensky. The goal consists in the analysis and reconstruction of the system of Raja yoga within the religious-ethical philosophy of the thinker. In the course of this research, the author resolves a number of problems: examines the system of primary elements of religious-ethical philosophy of M. V. Lodyzhensky; analyzes the sources that affected the formation of views of the philosopher upon Raja yoga; reveals main characteristics of the system of Raja yoga within Lodyzhensky&rsquo;s philosophy; determines the peculiarities of religious-mystical practice of Raja yoga in the philosophy of M. V. Lodyzhensky; defines the role of Raja-yoga within the system of religious-ethical philosophy of the thinker. The novelty lies in determination of the novel in comparison to the existing in scientific literature categories of M. V. Lodyzhensky&rsquo;s philosophy and their analysis in the context of system of fundamental sections of philosophical knowledge (ontology, theology, anthropology, epistemology, axiology, ethics); as well as in comprehensive study of the system of Raja yoga in interpretation Of M. V. Lodyzhensky and determination of its role within the structure of his philosophy. It is established that the &ldquo;core&rdquo; of the system of religious-ethical philosophy of M. V. Lodyzhensky is the ethics develop ethics and axiology of Hesychasm developed by him. It is proven that the system of metaphysical categories and ideas of the thinker is of synthetic nature and leans on various cultural trends and traditions. The article demonstrates that special role within the system of Lodyzhensky&rsquo;s philosophy is played by the apologetics of Hesychasm that implies critical review of the non-Christian mystical practices, among which is the examination of Raja yoga. The author underlines the uniqueness of interpretation of Raja yoga in the philosophy M. V. Lodyzhensky, as well as provides critical assessment to his interpretation of the system of Raja yoga.

scholarly journals Inverse estimation of soil hydraulic properties and water repellency following artificially induced drought stress

2018 ◽  
Vol 66 (2) ◽  
pp. 170-180 ◽  
Author(s):  
Vilim Filipović ◽  
Thomas Weninger ◽  
Lana Filipović ◽  
Andreas Schwen ◽  
Keith L. Bristow ◽  
...  
Keyword(s):  
Soil Water ◽  
Inverse Modeling ◽  
Hydraulic Properties ◽  
Global Climate ◽  
Water Repellency ◽  
Irrigation Event ◽  
Water Infiltration ◽  
Soil Hydraulic Properties ◽  
Soil Water Repellency ◽  
Soil Hydraulic

AbstractGlobal climate change is projected to continue and result in prolonged and more intense droughts, which can increase soil water repellency (SWR). To be able to estimate the consequences of SWR on vadose zone hydrology, it is important to determine soil hydraulic properties (SHP). Sequential modeling using HYDRUS (2D/3D) was performed on an experimental field site with artificially imposed drought scenarios (moderately M and severely S stressed) and a control plot. First, inverse modeling was performed for SHP estimation based on water and ethanol infiltration experimental data, followed by model validation on one selected irrigation event. Finally, hillslope modeling was performed to assess water balance for 2014. Results suggest that prolonged dry periods can increase soil water repellency. Inverse modeling was successfully performed for infiltrating liquids, water and ethanol, withR2and model efficiency (E) values both > 0.9. SHP derived from the ethanol measurements showed large differences in van Genuchten-Mualem (VGM) parameters for the M and S plots compared to water infiltration experiments. SWR resulted in large saturated hydraulic conductivity (Ks) decrease on the M and S scenarios. After validation of SHP on water content measurements during a selected irrigation event, one year simulations (2014) showed that water repellency increases surface runoff in non-structured soils at hillslopes.

Root effects on soil water and hydraulic properties

Biologia ◽  
2007 ◽  
Vol 62 (5) ◽  
Author(s):  
Horst Gerke ◽  
Rolf Kuchenbuch
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Water Content ◽  
Bulk Density ◽  
Soil Water ◽  
Soil Water Content ◽  
Hydraulic Properties ◽  
Soil Hydraulic Properties ◽  
Soil Hydraulic ◽  
Root Effects

AbstractPlants can affect soil moisture and the soil hydraulic properties both directly by root water uptake and indirectly by modifying the soil structure. Furthermore, water in plant roots is mostly neglected when studying soil hydraulic properties. In this contribution, we analyze effects of the moisture content inside roots as compared to bulk soil moisture contents and speculate on implications of non-capillary-bound root water for determination of soil moisture and calibration of soil hydraulic properties.In a field crop of maize (Zea mays) of 75 cm row spacing, we sampled the total soil volumes of 0.7 m × 0.4 m and 0.3 m deep plots at the time of tasseling. For each of the 84 soil cubes of 10 cm edge length, root mass and length as well as moisture content and soil bulk density were determined. Roots were separated in 3 size classes for which a mean root porosity of 0.82 was obtained from the relation between root dry mass density and root bulk density using pycnometers. The spatially distributed fractions of root water contents were compared with those of the water in capillary pores of the soil matrix.Water inside roots was mostly below 2–5% of total soil water content; however, locally near the plant rows it was up to 20%. The results suggest that soil moisture in roots should be separately considered. Upon drying, the relation between the soil and root water may change towards water remaining in roots. Relations depend especially on soil water retention properties, growth stages, and root distributions. Gravimetric soil water content measurement could be misleading and TDR probes providing an integrated signal are difficult to interpret. Root effects should be more intensively studied for improved field soil water balance calculations.

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