The role of naturally occurring organic compounds in causing soil water repellency

2013 ◽  
Vol 64 (5) ◽  
pp. 667-680 ◽  
Author(s):  
K. Mainwaring ◽  
I. L. Hallin ◽  
P. Douglas ◽  
S. H. Doerr ◽  
C. P. Morley
Keyword(s):  
Soil Water ◽  
Organic Compounds ◽  
Water Repellency ◽  
Soil Water Repellency ◽  
Naturally Occurring

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.

Water Shedding Properties of Oil Impregnated Hydrophobic Soils

2020 ◽  
Author(s):  
Rebecca McCerery ◽  
John Woodward ◽  
Glen McHale ◽  
Kate Winter
Keyword(s):  
Soil Water ◽  
Silicone Oil ◽  
Water Repellency ◽  
Contact Angles ◽  
Water Infiltration ◽  
Natural Soil ◽  
Particle Sizes ◽  
Soil Water Repellency ◽  
Water Contact ◽  
Naturally Occurring

<p>Hydrophobic soils and sediments have gained significant interest in soil science due to negatively influencing biomass production and as drivers of landslides and enhanced erosion. Whilst natural and fire-induced soil water repellency have been studied, little work has considered how the sediment-water interaction with naturally occurring hydrophobic sediments might change in the presence of oil. Recent advances in materials physics have shown bio-inspired slippery liquid infused porous surfaces (SLIPS) and lubricant impregnated surfaces (LIS) can produce super slippery surfaces with excellent water shedding properties. Here we apply this new understanding to the physics of soil water repellency and address how the presence of oil, whether from contamination or otherwise, might influence water infiltration. We hypothesise that oil impregnating a hydrophobic soil may create stable oil coatings and/or layers that create soil surfaces resistant to water infiltration and with enhanced run-off of water. Using monolayers of sand, silt and clay particles treated with a commercial hydrophobising agent and silicone oil, we created model (oil-free) hydrophobic and oil impregnated hydrophobic soils. Static water contact angles and droplet sliding angles were used to classify their degree of hydrophobicity and ability to shed water. Our results show that in the absence of oil, model hydrophobic soil surfaces with particle sizes below 63μm are superhydrophobic with water droplet contact angles above 150 degrees. In the presence of oil, we observed a sediment-based SLIP/LI surface on particle sizes below 63μm with water contact angles of 90 degrees and droplet sliding angles of below 5 degrees. We also achieved reduced sliding angles compared to the oil-free surfaces, and a conformal layer of oil on all particle sizes. These results support our hypothesis that SLIPS/LIS may occur in natural soil systems. These results have implications for soil water repellency, oil clean up from soil and for processes occurring in other sedimentary environments caused by both naturally occurring and anthropogenic contamination of oils.</p>

scholarly journals Predicting soil water repellency by hydrophobic organic compounds and their vegetation origin

2015 ◽  
Vol 2 (1) ◽  
pp. 153-186
Author(s):  
J. Mao ◽  
K. G. J. Nierop ◽  
M. Rietkerk ◽  
S. C. Dekker
Keyword(s):  
Fatty Acid ◽  
Soil Water ◽  
Organic Compounds ◽  
Hydroxy Fatty Acid ◽  
Soluble Fraction ◽  
Water Repellency ◽  
Primary Role ◽  
Plant Leaves ◽  
Hydrophobic Organic Compounds ◽  
Soil Water Repellency

Abstract. It is widely accepted that soil water repellency (SWR) is mainly caused by plant-derived hydrophobic organic compounds in soils; such hydrophobic compounds are defined as SWR-markers. However, the detailed influence of SWR-markers on SWR is yet unclear and the knowledge of their original sources is still limited. The aims of this study are to select important SWR-markers to predict SWR based on their correlation with SWR and to determine their origin. In our study, sandy soils with different SWR were collected, along with their covering vegetation, i.e. plant leaves/needles and roots. A sequential extraction procedure was applied to the soils to obtain three organic fractions: DCM / MeOH soluble fraction (D), DCM / MeOH insoluble fraction of IPA / NH3 extract (AI) and DCM / MeOH soluble fraction of IPA / NH3 extract (AS), which were subdivided into ten dominant SWR-marker groups: (D) fatty acid, (D) alcohol, (D) alkane, (AI) fatty acid, (AI) alcohol, (AI) ω-hydroxy fatty acid, (AI) α, ω-dicarboxylic acid, (AS) fatty acid, (AS) alcohol and (AS) ω-hydroxy fatty acid. Waxes and biopolyesters of the vegetation were also sequentially extracted from plants. In short, the soils with higher SWR have significantly higher relative concentrations of (AS) alcohols. A number of indications suggest that (AS) alcohols are mainly derived from roots and most likely produced by microbial hydrolysis of biopolyesters/suberins. In addition, the strong correlation between the biomarkers of plant tissues and SWR-markers in soils suggests that it is more accurate to predict SWR of topsoils using ester-bound alcohols from roots, and to predict SWR of subsoils using root-derived ω-hydroxy fatty acids and α, ω-dicarboxylic acids. Our analysis indicates that plant roots have a primary role influencing SWR relative to plant leaves.

The Role of Drop Volume and Number on Soil Water Repellency Determination

2013 ◽  
Vol 77 (5) ◽  
pp. 1732-1743 ◽  
Author(s):  
I. Hallin ◽  
P. Douglas ◽  
S.H. Doerr ◽  
R. Bryant
Keyword(s):  
Soil Water ◽  
Water Repellency ◽  
Drop Volume ◽  
Soil Water Repellency

Role of Divalent Fatty Acid Salts in Soil Water Repellency

2009 ◽  
Vol 73 (2) ◽  
pp. 541-549 ◽  
Author(s):  
E. R. Graber ◽  
S. Tagger ◽  
R. Wallach
Keyword(s):  
Fatty Acid ◽  
Soil Water ◽  
Water Repellency ◽  
Soil Water Repellency ◽  
Fatty Acid Salts ◽  
Acid Salts

scholarly journals Molecular Characterization of Burned Organic Matter at Different Soil Depths and Its Relationship with Soil Water Repellency: A Preliminary Result

Agronomy ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 2560
Author(s):  
Mirian de Deus ◽  
Ana Z. Miller ◽  
Nicasio T. Jiménez-Morillo
Keyword(s):  
Organic Matter ◽  
Soil Water ◽  
Molecular Characterization ◽  
Organic Compounds ◽  
Soil Layer ◽  
Water Repellency ◽  
Soil Water Repellency ◽  
Burned Soil ◽  
Soil Hydrophobicity

Soil water repellency (hydrophobicity) prevents water from wetting or infiltrating soils, triggering changes in the ecosystems. This physical property is directly correlated to the erodibility grade of a soil. Wildfire events may develop, enhance, or destroy soil hydrophobicity, modifying the erodibility grade of a soil and increasing the loss of its most reactive layer (organic matter). To assess the main organic family of compounds (biomarkers) surrogates to fire-induced water repellency, a study was carried out on a fire-affected soil under eucalyptus canopy at two depths (0–2 and 2–5 cm) from Portugal. The potential soil water repellency was measured using the water drop penetration time (WDPT) test. The molecular characterization of hydrophobic biomarkers was carried out using analytical pyrolysis (Py-GC/MS) in combination with multivariate statistical analysis (PCA, MLR). The upper burned soil layer (0–2 cm) displayed a significant contribution of fresh biomass (lignin and polysaccharides), while the deepest (2–5 cm) one showed more humified organic matter (lipids). The soil hydrophobicity was directly correlated to non-polar organic compounds, such as lipids and polycyclic aromatic hydrocarbons (PAHs), and inversely to unspecific aromatic compounds. The combination of mass spectrometry techniques and chemometric analysis allowed obtaining a preliminary forecast model of hydrophobicity degree in fire-affected soil samples under eucalyptus canopy. This analytical approach opens the door to developing more sensitive mathematical models using molecular organic compounds to predict the alteration of hydrophobicity and other soil physical properties induced by fires.

Soxhlet extraction of organic compounds associated with soil water repellency

2004 ◽  
Vol 2 (1) ◽  
pp. 41-44 ◽  
Author(s):  
Christopher T. Llewellyn ◽  
Stefan H. Doerr ◽  
Peter Douglas ◽  
Christopher P. Morley ◽  
Kathryn A. Mainwaring
Keyword(s):  
Soil Water ◽  
Organic Compounds ◽  
Soxhlet Extraction ◽  
Water Repellency ◽  
Soil Water Repellency
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