Changes in organic compound composition in soil following heating to maximum soil water repellency under anoxic conditions

2012 ◽  
Vol 9 (4) ◽  
pp. 369 ◽  
Author(s):  
I. Atanassova ◽  
S. H. Doerr ◽  
R. Bryant
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Soil Water ◽  
Water Repellency ◽  
Polar Compounds ◽  
Gas Chromatography Mass Spectrometry ◽  
Natural Soil ◽  
Soil Water Repellency ◽  
Chemical Changes ◽  
First Time

Environmental contextHeating of soils under wildfires can substantially reduce their ability to absorb rainfall, causing reduced vegetation recovery and increased erosion and flooding. This study examines, for the first time, the chemical changes in soil organic matter associated with heating in the oxygen-limited conditions typical under many wildfires. There was a noticeable tendency for production of non-polar compounds, which may ultimately contribute to a more persistent form of soil water repellency with important implications for managing fire affected terrain. AbstractSoil heating, as experienced during wildfires or management burns, can lead to extreme soil water repellency (WR). Previous work has focussed on the chemical composition of soil organic matter (SOM) that may be associated with WR in natural soil samples or samples heated in air. Under wildfires, however, oxygen supply is typically reduced and previous work has shown that the extreme WR induced under such conditions resists eventual destruction at temperatures ~200 °C higher than that of the same soil heated in air. This study examines, for the first time, the chemical changes in SOM associated with extreme WR following heating under oxygen limited conditions. Extracts obtained by accelerated solvent extraction (ASE), using mixtures of isopropyl alcohol/aqueous ammonia (IPA/NH3) and dichloromethane/methanol (DCM/MeOH), were analysed using gas chromatography–mass spectrometry (GC/MS). The data were compared with the SOM composition of the same soil unheated and following heating in air. In the absence of oxygen during soil heating, phthalic acid esters, substituted benzaldehydes, unsaturated amides and organophosphate esters were produced. In comparison with extracts of the same soil heated in air, there was a decreased methoxyphenol/phenol ratio, suggesting progressive demethoxylation and synthesis of new aromatic structures likely to promote extreme WR in soil.

Thermal destruction of soil water repellency and associated changes to soil organic matter as observed by FTIR spectroscopy

CATENA ◽  
2008 ◽  
Vol 74 (3) ◽  
pp. 205-211 ◽  
Author(s):  
Ivan Simkovic ◽  
Pavel Dlapa ◽  
Stefan H. Doerr ◽  
Jorge Mataix-Solera ◽  
Vlasta Sasinkova
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Ftir Spectroscopy ◽  
Soil Water ◽  
Thermal Destruction ◽  
Water Repellency ◽  
Soil Water Repellency

Soil water repellency persistence after recurrent forest fires on Mount Carmel, Israel

2013 ◽  
Vol 22 (4) ◽  
pp. 515 ◽  
Author(s):  
Naama Tessler ◽  
Lea Wittenberg ◽  
Noam Greenbaum
Keyword(s):  
Organic Matter ◽  
Soil Water ◽  
Forest Fires ◽  
Water Drop ◽  
Chemical Properties ◽  
Water Repellency ◽  
Mediterranean Ecosystem ◽  
Long Term Effects ◽  
Soil Water Repellency ◽  
Chemical Properties Of Soils

Variations in forest fires regime affect: (1) the natural patterns of community structure and vegetation; (2) the physico-chemical properties of soils and consequently (3) runoff, erosion and sediment yield. In recent decades the Mediterranean ecosystem of Mount Carmel, north-western Israel, is subjected to an increasing number of forest fires, thus, the objectives of the study were to evaluate the long-term effects of single and recurrent fires on soil water repellency (WR) and organic matter (OM) content. Water repellency was studied by applying water drop penetration time (WDPT) tests at sites burnt by single-fire, two fires, three fires and unburnt control sites. Water repellency in the burnt sites was significantly lower than in the unburnt control sites, and the soil maintained its wettability for more than 2 decades, whereas after recurrent fires, the rehabilitation was more complicated and protracted. The OM content was significantly lower after recurrent than after a single fire, causing a clear proportional decrease in WR. The rehabilitation of WR to natural values is highly dependent on restoration of organic matter and revegetation. Recurrent fires may cause a delay in recovery and reduced productivity of the soil for a long period.

Organic Matter Fractions Controlling Soil Water Repellency in Sandy Soils From the Doñana National Park (Southwestern Spain)

2014 ◽  
Vol 27 (5) ◽  
pp. 1413-1423 ◽  
Author(s):  
Nicasio T. Jiménez‐Morillo ◽  
José A. González‐Pérez ◽  
Antonio Jordán ◽  
Lorena M. Zavala ◽  
José María Rosa ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Water ◽  
National Park ◽  
Sandy Soils ◽  
Water Repellency ◽  
Soil Water Repellency ◽  
Doñana National Park ◽  
Organic Matter Fractions

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>

Soil water repellency of the artificial soil and natural soil in rocky slopes as affected by the drought stress and polyacrylamide

2018 ◽  
Vol 619-620 ◽  
pp. 401-409 ◽  
Author(s):  
Zhang Chen ◽  
Ruixin Wang ◽  
Pengyuan Han ◽  
Hailong Sun ◽  
Haifeng Sun ◽  
...  
Keyword(s):  
Drought Stress ◽  
Soil Water ◽  
Water Repellency ◽  
Artificial Soil ◽  
Natural Soil ◽  
Soil Water Repellency

Natural soil water repellency in different types of Mediterranean woodlands

Geoderma ◽  
2014 ◽  
Vol 226-227 ◽  
pp. 170-178 ◽  
Author(s):  
Lorena M. Zavala ◽  
Jorge García-Moreno ◽  
Ángel J. Gordillo-Rivero ◽  
Antonio Jordán ◽  
Jorge Mataix-Solera
Keyword(s):  
Soil Water ◽  
Water Repellency ◽  
Natural Soil ◽  
Soil Water Repellency ◽  
Different Types

The relationship of soil water repellency to aliphatic C and kaolin measured using DRIFT

Soil Research ◽  
2003 ◽  
Vol 41 (2) ◽  
pp. 251 ◽  
Author(s):  
I. McKissock ◽  
R. J. Gilkes ◽  
W. van Bronswijk
Keyword(s):  
Organic Matter ◽  
Soil Water ◽  
Soil Texture ◽  
Water Repellency ◽  
Water Repellent ◽  
Soil Water Repellency ◽  
Organic C ◽  
Aliphatic Carbon ◽  
Fourier Transform Spectra ◽  
Diffuse Reflectance Infrared

In general, water repellency by soil increases with the increase of total organic matter and decreases as the clay and silt contents of the soil increase. The prediction of water repellency from soil organic carbon (OC) content may be improved by examining the types of carbon associated with water repellency. This paper examines the hypothesis that measurement of aliphatic C can provide a better prediction of water repellency than measurement of total OC and also looks at the effects of soil texture on water repellency and the amount of aliphatic C in the soil. DRIFT (diffuse reflectance infrared fourier transform) spectra were measured on sandy soils from the West Midland Sandplains north of Perth in Western Australia. The areas of the aliphatic CH stretching signal (3000–2800/cm) and the OH stretching signal due to kaolin (3750–3570/cm) were used as relative measures of aliphatic carbon and kaolin contents. The relationships of aliphatic C and kaolin to water repellency have been examined and compared with the relationships of water repellency to total OC and clay contents of soil.Hydrophobic organic C as measured by DRIFT gave a better prediction of soil water repellency (r2 = 0.45) than did the total OC (r2 = 0.36). The specific hydrophobicity of organic matter (aliphatic C/OC ratio) increased as sand content increased. However, the direct influence of soil texture on water repellency was of more significance than its indirect influence on the amounts and forms of soil organic matter. A multivariate model including aliphatic C and clay + silt content was the best model for describing water repellency (r2 = 0.58). DRIFT is an effective, rapid method for screening soils for water repellent properties.For individual sand grains there was a weak positive relationship (r2 = 0.26) between the size of the aliphatic CH peak measured from surfaces of sand grains and the water repellency of the grains. A discontinuous aliphatic surface layer was present on the surface of individual sand grains.

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.

scholarly journals Short-term spatio-temporal spring grassland fire effects on soil colour, organic matter and water repellency in Lithuania

2013 ◽  
Vol 5 (2) ◽  
pp. 2119-2154 ◽  
Author(s):  
P. Pereira ◽  
X. Úbeda ◽  
J. Mataix-Solera ◽  
D. Martin ◽  
M. Oliva ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Water ◽  
Water Repellency ◽  
Fire Effects ◽  
Composite Sample ◽  
Soil Water Repellency ◽  
Short Term ◽  
Aggregate Fractions ◽  
Grassland Fire ◽  
Spatio Temporal

Abstract. The aim of this work was to study the short-term effects (first 9 months after the fire) of a low-severity spring boreal grassland fire on soil colour, soils organic matter (SOM) and soil water repellency (SWR) in Lithuania. Three days after the fire we designed a plot of 400 m2 in a control (unburned) and unburned area with the same geomorphological characteristics. Soil water repellency analysis were assessed through the 2 mm mesh (composite sample) and in the subsamples of all of the 250 samples divided into different soil aggregate fractions of 2–1, 1–0.5, 0.5–0.25 and < 0.25 mm, using the Water Drop Penetration Time (WDPT) method. The results showed that fire darkened the soil significantly during the entire study period due to the incorporation of ash/charcoal into the soil profile. Soil organic matter was significantly higher in the first two months after the fire in the burned plot, in comparison to the unburned plot. Soil water repellency (SWR) of the composite sample was higher in the burned plot during the first two months after the fire. However, considering the different aggregate fractions studied, the SWR was significantly higher until 5 months after the fire in the coarser fractions (2–1 mm, 1–0.5 mm) and 7 months after in the finer (0.5–0.25 mm and < 0.25 mm), suggesting that the leachability of organic compounds is different with respect to soil aggregate size fractions. This finding has implications for the spatio-temporal variability of fire effects on SWR. SOM was significantly negative correlated with SWR (composite sample) only in the two months after the fire. These results demonstrated that in the first two months the hydrophobic compounds produced by fire were one of the factors responsible for the increase in SWR. Subsequently repellent compounds were leached, at different rates, according to particle size. The impacts of this low severity grassland fire were limited in time, and are not considered a~threat to this ecosystem.

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