Hydrophobicity of soils affected by fires: An assessment using molecular markers from ultra-high resolution mass spectrometry

Morillo, N. T. Jiménez; Almendros, G.; Miller, Ana Z.; Hatcher, Patrick G.; González‐Pérez, José Antonío

doi:10.1016/j.scitotenv.2022.152957

Cited by 20 publications

(8 citation statements)

References 49 publications

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“…This is also corroborated by a prior characterization of our soil samples using solid-state 13 C NMR [ 15 ]. Particularly, the increase in UACs ( Table 2 ) together with the depletion of methoxyphenol (Lig) compounds observed in BAF (0–5 cm depth) ( Table S1 ), suggests that fire has triggered a defunctionalization of Lig compounds, as has been observed by other authors [ 23 , 46 ]. Alternatively, the origin for the UACs may also be the chemical alteration of terpene-like compounds and/or the cyclization of alkyl compounds through the Diels–Alder reaction [ 46 ].…”

Section: Resultssupporting

confidence: 74%

“…Furthermore, partially charred fragments of fire-affected standing vegetation may be deposited on the soil surface after fires. Usually, fire leads to a depletion of ligno-cellulosic and labile microbial-derived compounds and neoformation of C-condensed structures, conferring wider hydrophobicity and aromaticity indexes to SOM [ 19 , 20 , 21 , 22 , 23 ]. Together with a reduced soil microbial activity caused by fire [ 24 ], this partially explains the higher mean residence time of SOM observed in fire-affected soils compared to control sites [ 25 ].…”

Section: Introductionmentioning

confidence: 99%

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Soil Organic Matter Molecular Composition Shifts Driven by Forest Regrowth or Pasture after Slash-and-Burn of Amazon Forest

Leal

Morillo

González‐Pérez

et al. 2023

IJERPH

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Slash-and-burn of Amazon Forest (AF) for pasture establishment has increased the occurrence of AF wildfires. Recent studies emphasize soil organic matter (SOM) molecular composition as a principal driver of post-fire forest regrowth and restoration of AF anti-wildfire ambience. Nevertheless, SOM chemical shifts caused by AF fires and post-fire vegetation are rarely investigated at a molecular level. We employed pyrolysis–gas chromatography–mass spectrometry to reveal molecular changes in SOM (0–10, 40–50 cm depth) of a slash-burn-and-20-month-regrowth AF (BAF) and a 23-year Brachiaria pasture post-AF fire (BRA) site compared to native AF (NAF). In BAF (0–10 cm), increased abundance of unspecific aromatic compounds (UACs), polycyclic aromatic hydrocarbons (PAHs) and lipids (Lip) coupled with a depletion of polysaccharides (Pol) revealed strong lingering effects of fire on SOM. This occurs despite fresh litter deposition on soil, suggesting SOM minimal recovery and toxicity to microorganisms. Accumulation of recalcitrant compounds and slow decomposition of fresh forest material may explain the higher carbon content in BAF (0–5 cm). In BRA, SOM was dominated by Brachiaria contributions. At 40–50 cm, alkyl and hydroaromatic compounds accumulated in BRA, whereas UACs accumulated in BAF. UACs and PAH compounds were abundant in NAF, possibly air-transported from BAF.

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Section: Resultssupporting

confidence: 74%

Section: Introductionmentioning

confidence: 99%

Soil Organic Matter Molecular Composition Shifts Driven by Forest Regrowth or Pasture after Slash-and-Burn of Amazon Forest

Leal

Morillo

González‐Pérez

et al. 2023

IJERPH

Self Cite

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“…The spectral pre-processing treatments consisted of a light scatter and baseline correction by Standard Noise Variate (SNV), de-noising through a median filter, and mean centering [58]. This pre-processing has been widely used [44,58,91,92] to obtain forecasting models of different environmental and physical variables, using different analytical techniques (FT-IR, Py-CSIA, Py-GC/MS and FTICR/MS) on different natural matrices (e.g., soil, sediment, foodstuff). The protocol of this pre-processing is well exposed in [58].…”

Section: Discussionmentioning

confidence: 99%

Anthracological study of a Chalcolithic funerary deposit from Perdigões (Alentejo, Portugal): A new analytical methodology to establish the wood burning temperature

et al. 2023

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Anthracological analyses of charcoal samples retrieved from Pit 16 of Perdigões (Reguengos de Monsaraz, Portugal), a secondary deposition of cremated human remains dated back to the middle of the 3rd millennium BC, enabled the identification of 7 different taxa: Olea europaea, Quercus spp. (evergreen), Pinus pinaster, Fraxinus cf. angustifolia, Arbutus unedo, Cistus sp. and Fabaceae. All taxa are characteristic of both deciduous and evergreen Mediterranean vegetation, and this data might indicate that the gathering of woods employed for the human cremation/s occurred either on site, or in its vicinity. However, considering both the large distribution of the identified taxa and data about human mobility, it is not possible to conclusively determine the origin of the wood used in the cremation(s). Chemometric analysis were carried out to estimate the absolute burning temperature of woods employed for the human cremation/s. An in-lab charcoal reference collection was created by burning sound wood samples of the three main taxa identified from Pit 16, Olea europaea var. sylvestris, Quercus suber (evergreen type) and Pinus pinaster, at temperatures between 350 and 600 °C. The archaeological charcoal samples and the charcoal reference collection were chemically characterized by using mid-infrared (MIR) spectroscopy in the 1800–400 cm-1 range, and Partial Least Squares (PLS) regression method was used to build calibration models to predict the absolute combustion temperature of the archaeological woods. Results showed successful PLS forecasting of burn temperature for each taxon (significant (P <0.05) cross validation coefficients). The anthracological and chemometric analysis evidenced differences between the taxa coming from the two stratigraphic units within the Pit, SUs 72 and 74, suggesting that they may come from two different pyres or two different depositional moments.

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“…The intensity and spatial distribution of SWR often fluctuate seasonally with maximum coverage in the dry season and a decline in extent as precipitation inputs exceed the SWR critical water threshold (Bayad et al., 2020; Chau et al., 2014; DeBano, 1981; Hardie et al., 2012; Huffman et al., 2001; Rye & Smettem, 2018), with the maximum coverage of SWR appearing after a wildfire event or following extended periods of dryness during which hydrophobic conditions can be reestablished (Chen et al., 2019; Crockford et al., 1991; Hewelke et al., 2018). During a fire, surface soil or litter layer hydrophobic compounds vaporize, diffuse through soil capillaries, cool, and condense onto particles to form a subsurface layer of water‐repellent substrate (DeBano, 2000; Debano & Krammes, 1966; DeBano et al., 1979; Jiménez‐Morillo et al., 2022; Knicker, 2011). Because soils are an excellent insulator, fire‐derived hydrophobic layers are typically limited to the surface horizons of the soil profile, but their persistence, intensity, and extent vary tremendously across the landscape (Bodí et al., 2013; Debano et al., 1981; Debano et al., 1976; Dyrness, 1976; Huffman et al., 2001; Malvar et al., 2016; Woods et al., 2007).…”

Section: Introductionmentioning

confidence: 99%

Evaluating the occurrence and spatial patterns of soil water repellency in the Deschutes National Forest, Oregon

Weatherholt,

Johnson

2024

Soil Science Soc of Amer J

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High levels of soil water repellency (SWR) can hinder water infiltration and increase surface soil erosion risk and runoff. Although SWR occurs naturally in many areas, it is often patchy and does not impede water movement. However, fire can increase the connectedness and extent of SWR leading to topsoil loss, nutrient limitations, increased root water stress, and ultimately slower ecosystem recovery. This study examines the naturally hydrophobic soils of Oregon's Deschutes National Forest following the 2020 Green Ridge Fire to (1) examine the relationship between SWR and management‐relevant burn severity classes, (2) quantify an appropriate spatial scale over which to evaluate SWR properties, and (3) determine which environmental factors drive patterns in SWR. We found that the top 1–3 cm of soil became less hydrophobic after fire, while the profile to about 10 cm became more uniformly hydrophobic. This could indicate that surface soil is more prone to post‐fire erosion in burned areas. However, predicting SWR is still challenging. While burn severity and environmental metrics did statistically account for some variation in SWR following fire, the range of SWR spatial autocorrelation was at best a few meters. Due to this fine‐scale variation, future work should focus on determining an efficient post‐fire soil evaluation protocol with adequate density and scale of sampling while also incorporating the influence of environmental factors to inform management decisions.

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Hydrophobicity of soils affected by fires: An assessment using molecular markers from ultra-high resolution mass spectrometry

Cited by 20 publications

References 49 publications

Soil Organic Matter Molecular Composition Shifts Driven by Forest Regrowth or Pasture after Slash-and-Burn of Amazon Forest

Soil Organic Matter Molecular Composition Shifts Driven by Forest Regrowth or Pasture after Slash-and-Burn of Amazon Forest

Anthracological study of a Chalcolithic funerary deposit from Perdigões (Alentejo, Portugal): A new analytical methodology to establish the wood burning temperature

Evaluating the occurrence and spatial patterns of soil water repellency in the Deschutes National Forest, Oregon

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