scholarly journals Decadal-scale shifts in soil hydraulic properties as induced by altered precipitation

2019 ◽  
Vol 5 (9) ◽  
pp. eaau6635 ◽  
Author(s):  
Joshua S. Caplan ◽  
Daniel Giménez ◽  
Daniel R. Hirmas ◽  
Nathaniel A. Brunsell ◽  
John M. Blair ◽  
...  
Keyword(s):  
Hydraulic Properties ◽  
Terrestrial Ecosystems ◽  
Soil Hydraulic Properties ◽  
Infiltration Rates ◽  
Precipitation Regimes ◽  
Decadal Scale ◽  
Pore Blockage ◽  
Plant Available Water ◽  
Soil Hydraulic ◽  
Precipitation Manipulation Experiment

Soil hydraulic properties influence the partitioning of rainfall into infiltration versus runoff, determine plant-available water, and constrain evapotranspiration. Although rapid changes in soil hydraulic properties from direct human disturbance are well documented, climate change may also induce such shifts on decadal time scales. Using soils from a 25-year precipitation manipulation experiment, we found that a 35% increase in water inputs substantially reduced infiltration rates and modestly increased water retention. We posit that these shifts were catalyzed by greater pore blockage by plant roots and reduced shrink-swell cycles. Given that precipitation regimes are expected to change at accelerating rates globally, shifts in soil structure could occur over broad regions more rapidly than expected and thus alter water storage and movement in numerous terrestrial ecosystems.

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>

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

scholarly journals Pinhole Multistep Centrifuge Outflow Method for Estimating Unsaturated Hydraulic Properties with Small Volume Soil Samples

Water ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1169
Author(s):  
Long Thanh Bui ◽  
Yasushi Mori
Keyword(s):  
Hydraulic Properties ◽  
Volcanic Ash ◽  
Small Volume ◽  
Clayey Soil ◽  
Soil Hydraulic Properties ◽  
Retention Curve ◽  
Volcanic Ash Soil ◽  
Equilibrium Data ◽  
Soil Hydraulic ◽  
Water Holding

If soil hydraulic conductivity or water holding capacity could be measured with a small volume of samples, it would benefit international fields where researchers can only carry a limited amount of soils out of particular regions. We performed a pinhole multistep centrifuge outflow method on three types of soil, which included granite decomposed soil (Masa soil), volcanic ash soil (Andisol soil), and alluvial clayey soil (paddy soil). The experiment was conducted using 2 mL and 15 mL centrifuge tubes in which pinholes were created on the top and bottom for air intrusion and outflow, respectively. Water content was measured at 5, 15, and 30 min after applying the centrifuge to examine the equilibrium time. The results showed that pinhole drainage worked well for outflow, and 15 or 30 min was sufficient to obtain data for each step. Compared with equilibrium data, the retention curve was successfully optimized. Although the curve shape was similar, unsaturated hydraulic conductivities deviated largely, which implied that Ks caused convergence issues. When Ks was set as a measured constant, the unsaturated hydraulic properties converged well and gave excellent results. This method can provide soil hydraulic properties of regions where soil sampling is limited and lacks soil data.

scholarly journals The effects of long-term fertilizations on soil hydraulic properties vary with scales

2021 ◽  
Vol 593 ◽  
pp. 125890
Author(s):  
Xiaoxian Zhang ◽  
Andrew L. Neal ◽  
John W. Crawford ◽  
Aurelie Bacq-Labreuil ◽  
Elsy Akkari ◽  
...  
Keyword(s):  
Hydraulic Properties ◽  
Soil Hydraulic Properties ◽  
Soil Hydraulic
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