Does water repellency of pyrochars and hydrochars counter their positive effects on soil hydraulic properties?

Geoderma ◽  
2015 ◽  
Vol 245-246 ◽  
pp. 31-39 ◽  
Author(s):  
Nina Eibisch ◽  
Wolfgang Durner ◽  
Michel Bechtold ◽  
Roland Fuß ◽  
Robert Mikutta ◽  
...  
Keyword(s):  
Hydraulic Properties ◽  
Water Repellency ◽  
Soil Hydraulic Properties ◽  
Positive Effects ◽  
Soil Hydraulic

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.

Microplastic enhances water repellency of soils

2020 ◽  
Author(s):  
Andreas Cramer ◽  
Ursula Bundschuh ◽  
Pascal Bernard ◽  
Mohsen Zarebanadkouki ◽  
Andrea Carminati
Keyword(s):  
Hydraulic Properties ◽  
Sessile Drop ◽  
Chemical Properties ◽  
Water Repellency ◽  
Terrestrial Ecosystems ◽  
Contact Angles ◽  
Water Retention Curve ◽  
Soil Hydraulic Properties ◽  
Soil Hydraulic ◽  
The Impact

<p>Soils are the largest sink of microplastic particles (MPP) in terrestrial ecosystems. However, there is little knowledge on the implication of MPP contaminating soils. In particular, we don’t know how MPP move and, on the other hand, how they affect soil hydraulic properties and soil moisture dynamics.</p><p>Among the expected effects of MPP on soil hydraulic properties is the likelihood that MPP enhances soil water repellency. This emerges from (1) the MPP surface chemical properties as well as (2) their surface physical properties like size and shape. Here, we tested mixtures of MPP and a model porous media. The Sessile Drop Method was applied and apparent contact angles were measured. We are able to show enlarged contact angles with rising concentrations of MPP. Already in relatively low concentrations of MPP the contact angels exhibit a steep increase and are rapidly reaching areas of super-hydrophobicity. Furthermore, we provide the physical explanation of the apparent contact angles resulting from the three-phase contact line between solid composite surfaces, water and air. The considered modes of a droplet lying on a surface are Wenzel, Cassie-Baxter and Young. The goal here was to differentiate between the involved surfaces building up the apparent contact angle and to pin down the impact of MPP in these systems.</p><p>Thinking about the implications of these results, an increased water repellency alters soil hydraulic properties towards less water content resulting in a shift in the water retention curve. Less water in soils especially at sites of high MPP concentrations leads to a limitation of degradation of MPP by hydrolysis. Additionally, microorganisms themselves and their enzymes cannot migrate in the liquid phase towards the MPP even elongating the process of natural purification.</p>

Relations between soil hydraulic properties and burn severity

2016 ◽  
Vol 25 (3) ◽  
pp. 279 ◽  
Author(s):  
John A. Moody ◽  
Brian A. Ebel ◽  
Petter Nyman ◽  
Deborah A. Martin ◽  
Cathelijne Stoof ◽  
...  
Keyword(s):  
Hydraulic Properties ◽  
Water Repellency ◽  
Threshold Value ◽  
Burn Severity ◽  
Soil Cores ◽  
Soil Hydraulic Properties ◽  
Empirical Relations ◽  
Cumulative Infiltration ◽  
Soil Hydraulic ◽  
Inverse Functions

Wildfire can affect soil hydraulic properties, often resulting in reduced infiltration. The magnitude of change in infiltration varies depending on the burn severity. Quantitative approaches to link burn severity with changes in infiltration are lacking. This study uses controlled laboratory measurements to determine relations between a remotely sensed burn severity metric (dNBR, change in normalised burn ratio) and soil hydraulic properties (SHPs). SHPs were measured on soil cores collected from an area burned by the 2013 Black Forest fire in Colorado, USA. Six sites with the same soil type were selected across a range of burn severities, and 10 random soil cores were collected from each site within a 30-m diameter circle. Cumulative infiltration measurements were made in the laboratory using a tension infiltrometer to determine field-saturated hydraulic conductivity, Kfs, and sorptivity, S. These measurements were correlated with dNBR for values ranging from 124 (low severity) to 886 (high severity). SHPs were related to dNBR by inverse functions for specific conditions of water repellency (at the time of sampling) and soil texture. Both functions had a threshold value for dNBR between 124 and 420, where Kfs and S were unchanged and equal to values for soil unaffected by fire. For dNBRs >~420, the Kfs was an exponentially decreasing function of dNBR and S was a linearly decreasing function of dNBR. These initial quantitative empirical relations provide a first step to link SHPs to burn severity, and can be used in quantitative infiltration models to predict post-wildfire infiltration and resulting runoff.

scholarly journals Estimation of the soil hydraulic properties from the transient infiltration curve measured on soils affected by water repellency

CATENA ◽  
2019 ◽  
Vol 178 ◽  
pp. 298-306 ◽  
Author(s):  
D. Moret-Fernández ◽  
B. Latorre ◽  
M.L. Giner ◽  
J. Ramos ◽  
C.L. Alados ◽  
...  
Keyword(s):  
Hydraulic Properties ◽  
Water Repellency ◽  
Soil Hydraulic Properties ◽  
Soil Hydraulic

A modified upward infiltration method for characterizing soil hydraulic properties

2002 ◽  
Vol 66 (1) ◽  
pp. 57 ◽  
Author(s):  
M. H. Young ◽  
A. Karagunduz ◽  
J. Šimůnek ◽  
K. D. Pennell
Keyword(s):  
Hydraulic Properties ◽  
Soil Hydraulic Properties ◽  
Soil Hydraulic ◽  
Infiltration Method
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