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

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.

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Induced uneven spatial distribution of agrochemicals due to preferential flow in water repellent soils and its remediation by surfactant

10.5194/egusphere-egu2020-2974 ◽

2020 ◽

Author(s):

Felix Abayomi Ogunmokun ◽

Rony Wallach

Keyword(s):

Spatial Distribution ◽

Soil Water ◽

Soil Profile ◽

Preferential Flow ◽

Sandy Soils ◽

Water Repellency ◽

Treated Wastewater ◽

Water Repellent ◽

Soil Water Repellency ◽

Mediterranean Countries

<p>Soil water repellency is a common feature of dry soils under permanent vegetation and drought conditions. Soil-water hydrology is markedly affected by soil-water repellency as it hinders infiltration, leading to enhanced surface runoff and soil erosion. Although this phenomenon was primarily ascribed to sandy soils, it has been observed in loam, clay, and peat soils in dry and humid regions. One detrimental effect of soil water repellency on plants is the reduction of soil water availability that stems from the non-uniform water retention and flow in preferential pathways (gravity-induced fingers) with relatively dry soil volume among these paths. It was recently discovered that prolonged irrigation with treated wastewater, a widely used alternative in Israel and other Mediterranean countries due to the limited freshwater, triggers soil water repellency which invariably resulted in preferential flow development in the field. Due to climate change events, the use of treated wastewater for irrigation as a means of freshwater conservation is expected to widen, including in countries that are not considered dry.</p><p>While a vast amount of research has been devoted to characterizing the preferential flow in water repellent soils, the effect of this flow regime on the spatial distribution of salt and fertilizers in the root zone was barely investigated. Results from a commercial citrus orchard irrigated with treated wastewater that includes the spatial and temporal distribution of preferential flow in the soil profile measured by ERT will be demonstrated. The associated spatial distribution of salinity, nitrate, phosphate, and SAR in the soil profile will be shown as well.&#160; We investigated the efficacy of two nonionic surfactants application to remediate hydrophobic sandy soils both in the laboratory and field. The effect of the surfactant application to the water repellent soils in the orchards on the spatial distribution of soil moisture and the associated agrochemicals will be presented and discussed.</p>

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Relating soil organic matter composition to soil water repellency for soil biopore surfaces different in history from two Bt horizons of a Haplic Luvisol

Ecohydrology ◽

10.1002/eco.1949 ◽

2018 ◽

Vol 11 (6) ◽

pp. e1949 ◽

Cited By ~ 11

Author(s):

C. Haas ◽

H.H. Gerke ◽

R.H. Ellerbrock ◽

P.D. Hallett ◽

R. Horn

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Soil Water ◽

Water Repellency ◽

Soil Water Repellency ◽

Organic Matter Composition ◽

Soil Organic Matter Composition

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Effect of sample disturbance on soil water repellency determination in sandy soils

Geoderma ◽

10.1016/j.geoderma.2006.01.007 ◽

2006 ◽

Vol 136 (1-2) ◽

pp. 11-19 ◽

Cited By ~ 22

Author(s):

E.R. Graber ◽

O. Ben-Arie ◽

R. Wallach

Keyword(s):

Soil Water ◽

Sandy Soils ◽

Water Repellency ◽

Soil Water Repellency ◽

Sample Disturbance

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

Soil Research ◽

10.1071/sr01091 ◽

2003 ◽

Vol 41 (2) ◽

pp. 251 ◽

Cited By ~ 32

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.

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Experimental characterization of the impact of temperature and humidity on the breakdown of soil water repellency in sandy soils and composts

Hydrological Processes ◽

10.1002/hyp.10305 ◽

2014 ◽

Vol 29 (8) ◽

pp. 2065-2073 ◽

Cited By ~ 7

Author(s):

Amii Whelan ◽

Cedric Kechavarzi ◽

Frederic Coulon ◽

Stefan H. Doerr

Keyword(s):

Soil Water ◽

Sandy Soils ◽

Water Repellency ◽

Experimental Characterization ◽

Soil Water Repellency ◽

Temperature And Humidity ◽

The Impact

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

Environmental Chemistry ◽

10.1071/en11122 ◽

2012 ◽

Vol 9 (4) ◽

pp. 369 ◽

Cited By ~ 3

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.

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

Agronomy ◽

10.3390/agronomy11122560 ◽

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.

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

Solid Earth Discussions ◽

10.5194/sed-5-2119-2013 ◽

2013 ◽

Vol 5 (2) ◽

pp. 2119-2154 ◽

Cited By ~ 5

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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Soil water repellency changes with depth and relationship to physical properties within wettable and repellent soil profiles

Journal of Hydrology and Hydromechanics ◽

10.1515/johh-2016-0055 ◽

2017 ◽

Vol 65 (1) ◽

pp. 99-104 ◽

Cited By ~ 6

Author(s):

Nasrollah Sepehrnia ◽

Mohammad Ali Hajabbasi ◽

Majid Afyuni ◽

Ľubomír Lichner

Keyword(s):

Organic Matter ◽

Soil Water ◽

Subcritical Water ◽

Water Repellency ◽

Moisture Distribution ◽

Water Repellent ◽

Soil Profiles ◽

Soil Water Repellency ◽

Major Property ◽

Dry Water

AbstractThis study explored the effect of soil water repellency (SWR) on soil hydrophysical properties with depth. Soils were sampled from two distinctly wettable and water repellent soil profiles at depth increments from 0-60 cm. The soils were selected because they appeared to either wet readily (wettable) or remain dry (water repellent) under field conditions. Basic soil properties (MWD, SOM, θv) were compared to hydrophysical properties (Ks, Sw, Se, Sww, Swh, WDPT, RIc, RImand WRCT) that characterise or are affected by water repellency. Our results showed both soil and depth affected basic and hydrophysical properties of the soils (p <0.001). Soil organic matter (SOM) was the major property responsible for water repellency at the selected depths (0-60). Water repellency changes affected moisture distribution and resulted in the upper layer (0-40 cm) of the repellent soil to be considerably drier compared to the wettable soil. The water repellent soil also had greater MWDdryand Ks over the entire 0-60 cm depth compared to the wettable soil. Various measures of sorptivity, Sw, Se, Sww, Swh, were greater through the wettable than water repellent soil profile, which was also reflected in field and dry WDPT measurements. However, the wettable soil had subcritical water repellency, so the range of data was used to compare indices of water repellency. WRCT and RImhad less variation compared to WDPT and RIc. Estimating water repellency using WRCT and RIm indicated that these indices can detect the degree of SWR and are able to better classify SWR degree of the subcritical-repellent soil from the wettable soil.

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