scholarly journals Water stable aggregates of Japanese Andisol as affected by hydrophobicity and drying temperature

2014 ◽  
Vol 62 (2) ◽  
pp. 97-100 ◽  
Author(s):  
D.A.L. Leelamanie ◽  
Jutaro Karube
Keyword(s):  
Contact Angle ◽  
Sessile Drop ◽  
Water Drop ◽  
Aggregate Stability ◽  
Water Repellency ◽  
Water Stability ◽  
Drying Temperature ◽  
Hydrophobic Materials ◽  
Soil Hydrophobicity ◽  
Penetration Time

Abstract Hydrophobicity is a property of soils that reduces their affinity for water, which may help impeding the pressure build-up within aggregates, and reducing aggregate disruption. The purpose of this study was to examine the relation of soil hydrophobicity and drying temperature to water stability of aggregates while preventing the floating of dry aggregates using unhydrophobized and hydrophobized surface Andisol. Soil was hydrophobized using stearic acid into different hydrophobicities. Hydrophobicity was determined using sessile drop contact angle and water drop penetration time (WDPT). Water stability of aggregates (%WSA) was determined using artificially prepared model aggregates. The %WSA increased as the contact angle and WDPT increased. Contact angle and WDPT, which provided maximum %WSA showing less than 1 s of floating, was around 100° and 5 s, respectively. Although the %WSA gradually increased with increasing contact angle and WDPT above this level, high levels of hydrophobicity initiated aggregate floating, which would cause undesirable effects of water repellency. Heating at 50°C for 5 h d-1 significantly affected %WSA and hydrophobicity in hydrophobized samples, but did not in unhydrophobized samples. The results indicate that the contact angle and wetting rate (WDPT) are closely related with the water stability of aggregates. The results further confirm that high levels of hydrophobicities induce aggregate floating, and the drying temperature has differential effects on hydrophobicity and aggregate stability depending on the hydrophobic materials present in the soil.

Clay effects on the contact angle and water drop penetration time of model soils

2010 ◽  
Vol 56 (3) ◽  
pp. 371-375 ◽  
Author(s):  
D. A. L. Leelamanie ◽  
Jutaro Karube ◽  
Aya Yoshida
Keyword(s):  
Contact Angle ◽  
Water Drop ◽  
Penetration Time

Effect of secondary succession in abandoned fields on some properties of acidic sandy soils

2020 ◽  
Author(s):  
Peter Surda ◽  
Lubomir Lichner ◽  
Viliam Nagy
Keyword(s):  
Pore Size ◽  
Secondary Succession ◽  
Water Drop ◽  
Sandy Soils ◽  
Water Repellency ◽  
Organic Carbon Content ◽  
Abandoned Fields ◽  
Water Sorptivity ◽  
The Impact ◽  
Penetration Time

<p>Abandonment of agricultural lands in recent decades is occurring mainly in Europe, North America and Oceania, and changing the fate of landscapes as the ecosystem recovers during fallow stage. The objective of this study was to find the impact of secondary succession in abandoned fields on some parameters of acidic sandy soils in the Borská nížina lowland (southwestern Slovakia). We investigated soil chemical (pH and soil organic carbon content), hydrophysical (water sorptivity, and hydraulic conductivity), and water repellency (water drop penetration time, water repellency cessation time, repellency index, and modified repellency index) parameters, as well as the ethanol sorptivity of the studied soils. Both the hydrophysical and chemical parameters decreased significantly during abandonment of the three investigated agricultural fields. On the other hand, the water repellency parameters increased significantly, but the ethanol sorptivity did not change during abandonment. As the ethanol sorptivity depends mainly on soil pore size, the last finding could mean that the pore size of acidic sandy soils did not change during succession.</p>

scholarly journals Effects of a Canary pine forest wildfire (Tenerife, Canary Islands, summer 2007) on selected soil properties and their relationship with short- to medium-term soil water repellency .

2014 ◽  
Vol 2 ◽  
Author(s):  
Alexis Hernández ◽  
Natalia Rodríguez ◽  
Marcelino del Arco ◽  
Carmen Dolores Arbelo ◽  
Jesús Notario del Pino ◽  
...  
Keyword(s):  
Soil Properties ◽  
Soil Water ◽  
Forest Fires ◽  
Sampling Site ◽  
Aggregate Stability ◽  
Water Repellency ◽  
Pine Forest ◽  
Soil Water Repellency ◽  
Soil Hydrophobicity ◽  
The Impact

Forest fires modify the soil environment, often triggering severe soil degradation. In this paper, we studied the impact of a large northern Tenerife Canariy pine forest wildfire on a set of relevant soil properties, focusing on their evolution in time and relationship with soil water repellency. To do this, soils were sampled at four sites (burned and non-burned) and several soil physical and chemical parameters were measured. The results show significant variations for soil pH, electric conductivity (CE<sub>1:5</sub>), and NH<sub>4</sub><sup>+</sup>-N between burned and non-burned samples, whereas non-significant increases were found in burned soils for oxidizable carbon (C<sub>ox</sub>), total nitrogen (N<sub>tot</sub>) , Ca<sup>2+</sup>, Mg<sup>2+</sup>, Na<sup>+</sup> and K<sup>+</sup>, and soil hydrophobicity. The differences caused by the fire were no longer evident one year later. Furthermore, in one sampling site (Vitric Leptosols under low pine forest with a mixed heath/beech tree understory) a wide variation in the content of C<sub>ox</sub> and N<sub>tot</sub> and high water repellency was observed relative to the other sites. These differences can be attributed to the composition of the understory vegetation. Significant correlations between soil hydrophobicity with CE<sub>1:5</sub>, aggregate stability and the contents of C<sub>ox</sub>, N<sub>tot</sub>, NH<sub>4</sub><sup>+</sup>-N, Ca<sup>2+</sup>, Mg<sup>2+</sup>, Na<sup>+</sup> and K<sup>+</sup> were found.

How are mineral and organic phases regulating burning-induced soil water repellency? Unravelling the crucial dynamics occurring in the Alps even at moderate fire intensities.

2021 ◽  
Author(s):  
Sara Negri ◽  
Beatrice Giannetta ◽  
Daniel Said-Pullicino ◽  
Luisella Celi ◽  
Eleonora Bonifacio
Keyword(s):  
Water Drop ◽  
Aggregate Stability ◽  
Water Repellency ◽  
Beech Forest ◽  
Mineral Surfaces ◽  
Litter Cover ◽  
Coarse Texture ◽  
Fe Speciation ◽  
Ft Ir ◽  
Terrestrial Biomes

&lt;p&gt;Wildfires play the role of ecosystem shapers in the majority of terrestrial biomes, altering canopy and litter cover and imposing strong modifications on soils. Organic matter (OM) content and composition, mineralogy, pH, aggregate stability and water repellency (WR) are among the main edaphic properties to be affected by heat. Various studies dealt with occurrence, extent and persistence of burning-induced soil WR, but the dynamics at the basis of its formation (and loss) are still widely unclear. In addition, the vast majority of research on this topic has been carried out in the Mediterranean, even if alpine environments are far from being untouched by fires. Our aims were therefore to provide insight into the key mechanisms regulating WR thermal alterations in a relatively understudied environment.&lt;/p&gt;&lt;p&gt;Our sampling design aimed at collecting soils representative of the Western Italian Alps. Charring was simulated in the lab, at increasing temperatures (up to 300&amp;#176; C), on a set of A soil horizons developed under pine and beech forest covers. Water drop penetration time (WDPT) was employed to test WR persistence. Soils were analyzed in terms of organic carbon (OC) and nitrogen contents, pH, texture and iron (Fe) oxides composition (Fe-DCB and Fe-pyrophosphate extracted). Fe-speciation and OM composition of some selected samples were further characterized using Fe K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy and Fourier transform-infra red (FT-IR) spectroscopy, respectively.&lt;/p&gt;&lt;p&gt;WR was found to be extremely variable, event at room temperature. For samples exhibiting an increase in WR upon burning intensity, maximum repellency was observed at 200&amp;#176; C. OC abundance (%) and coarse texture were found to be the main drivers of hydrophobicity in soil. WR was drastically lost when samples were exposed to temperatures higher than 200&amp;#176;C. Above this threshold, pH systematically increased and OC (%) sharply decreased. The increasingly negative charge of mineral surfaces, mirrored by pH increase, seems to result in a significant C volatilization by OM desorption, eventually leading to a super-hydrophilic behavior in soil.&lt;/p&gt;&lt;p&gt;Fe EXAFS allowed to evaluate different thermal-dictated pathways of Fe-speciation. The formation of more crystalline Fe-forms (e.g. hematite, meghemite) was observed above 200&amp;#176; C. Even though a reduction in surface area should be expected when observing an increase in crystallization degree (potentially giving rise to greater WR), OM adhesion to mineral surfaces seems to be inhibited by the change induced in their charge. A reduction in the OM-bound Fe pool (pyrophosphate extracted) above 200&amp;#176; C could be appreciated, supporting the interpretation of oxy-hydroxides transformations and OC (%) loss. &amp;#160;&lt;/p&gt;&lt;p&gt;The current investigation has been carried out to capture an in-depth picture of wildfire impacts on alpine soils, targeting factors responsible for WR enhancement and shred. Identifying the mechanisms regulating wildfire-related WR is a key issue, as the formation of hydrophobic layers in soil highly favors its erosion. Addressing such matters is crucial to tackle the issue of ecosystems recovery, considering that climate-change-related alterations in wildfires regimes are already causing the occurrence of more frequent and disruptive fires.&lt;/p&gt;

scholarly journals Soil hydrophobicity: comparative study of usual determination methods

2015 ◽  
Vol 45 (2) ◽  
pp. 260-266 ◽  
Author(s):  
Eduardo Saldanha Vogelmann ◽  
José Miguel Reichert ◽  
Juliana Prevedello ◽  
Gabriel Oladele Awe ◽  
Dalvan José Reinert
Keyword(s):  
Water Drop ◽  
Soil Layer ◽  
Organic Matter Content ◽  
Soil Samples ◽  
Water Infiltration ◽  
Water Repellent ◽  
Hydrophobicity Index ◽  
Coefficients Of Variation ◽  
Soil Hydrophobicity ◽  
Penetration Time

Hydrophobic or water repellent soils slowly absorb water because of the low wett ability of the soil particles which are coated with hydrophobic organic substances. These pose significant effects on plant growth, water infiltration and retention, surface runoff and erosion. The objective of this study was to compare the performance of tension micro-infiltrometer(TMI) and the water drop penetration time (WDPT) methods in the determination of the hydrophobicity index of eighteen soils from southern Brazil. Soil samples were collected from the 0-5cm soil layer to determine particle size distribution, organic matter content, hydrophobicity index of soil aggregates and droplet penetration time of disaggregated and sieved soil samples. For the TMI method the soil samples were subjected to minor changes due to the use of macroaggregates to preserve the distribution of solid constituents in the soil. Due to the homogeneity of the soil samples the WDPT method gave smaller coefficients of variation unlike the TMI method where the soil structure is preserved. However, both methods had low coefficients of variation, and are thus effective for determining the soil hydrophobicity, especially when the log hydrophobicity index or log WDPT is >1.

Water repellency of soils with various content of organic matter in north-eastern Poland

2013 ◽  
Vol 64 (2) ◽  
pp. 30-33 ◽  
Author(s):  
Mirosław Orzechowski ◽  
Sławomir Smólczyński ◽  
Paweł Sowiński ◽  
Beata Rybińska
Keyword(s):  
Organic Matter ◽  
Water Drop ◽  
Peat Soil ◽  
Water Repellency ◽  
Organic Soil ◽  
Soil Protection ◽  
North Eastern ◽  
Time Test ◽  
Penetration Time ◽  
Properties Of Soil

Abstract The objective of the work was to investigate hydrophobic properties of soil formations with various amounts of organic matter and occurring in young glacial landscape. The research was carried out in mineral, mineral-organic and organic (slightly and strongly silted mucks, sedge peat, alder wood peat, reed peat) soil formations. Water repellency is very important in soil protection. It favors the formation of stable aggregates and prevents from soil erosion. The study was carried out applying two methods . water drop penetration time test (WDPT) and alcohol percentage test (AP). Among 51 analyzed soil samples in WDPT test, 64.7% of mineral and mineral-organic soil formations were hydrophilic. Among organic soil formations 37.6% was slightly and strongly hydrophobic and they represented strongly silted mucks. Unsilted and slightly silted mucks, weakly and strongly decomposed peats, were very strongly (18.8%) and extremely (43.6%) hydrophobic. AP test showed that strongly silted mucks were moderately and very strongly hydrophobic. Slightly silted mucks, and peats were very strongly and extremely hydrophobic. It can be stated that water repellency decreases simultaneously with the degree of siltation of organic soil formations.

The impact of heating on the hydraulic properties of soils sampled under different plant cover

Biologia ◽  
2009 ◽  
Vol 64 (3) ◽  
Author(s):  
Viliam Novák ◽  
Ľubomír Lichner ◽  
Bin Zhang ◽  
Karol Kňava
Keyword(s):  
Hydraulic Conductivity ◽  
Soil Water ◽  
Water Retention ◽  
Water Drop ◽  
Sampling Site ◽  
Water Repellency ◽  
Saturated Hydraulic Conductivity ◽  
Soil Water Repellency ◽  
The Impact ◽  
Penetration Time

AbstractThe impact of heating on the peristence of water repellency, saturated hydraulic conductivity, and water retention characteristics was examined on soils from both forest and meadow sites in southwest Slovakia shortly after a wet spell. The top 5 cm of meadow soils had an initial water drop penetration time WDPT at 20°C of 457 s, whereas WDPT in the pine forest was 315 s for the top 5 cm and 982 s if only the top 1 cm was measured. Heating soils at selected temperatures of 50, 100, 150, 200, 250 and 300°C caused a marked drop in water drop penetration time WDPT from the initial value at 20°C. However, samples collected in different years and following an imposed cycle of wetting and drying showed much different trends, with WDPT sometimes initially increasing with temperature, followed by a drop after 200–300°C. The impact of heating temperature on the saturated hydraulic conductivity of soil was small. It was found for both the drying and wetting branches of soil water retention curves that an increase in soil water repellency resulted in a drop in soil water content at the same matric potential. The persistence of soil water repellency was strongly influenced by both the sampling site and time of sampling, as it was characterized by the results of WDPT tests.

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