Variability of the quality and quantity of organic matter in soil affected by multiple wildfires

López-Martín, María Elena; Velasco-Molina, Marta; Knicker, Heike

doi:10.1007/s11368-015-1223-2

Cited by 24 publications

(22 citation statements)

References 37 publications

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“…soil heating) (Inbar et al, 2014;Doerr et al, 2017), and as observed in previous studies (Dodonov et al, 2014;Lombao et al, 2015). Different types of fuel, pack, density, connectivity and moisture induce different conditions of combustion, heat release and, therefore, impacts on soil (Merino et al, 2015;López-Martín et al, 2016). After the intense rainfall, we observed an increase in the relationship between certain variables and a reduction in spatial variability, which can be attributed to the decrease in the dispersion of the data values relative to the mean.…”

Section: Descriptive Statistics Correlations and Pcasupporting

confidence: 84%

Mapping impact of intense rainfall on a high-severity burned area using principal component analysis

Francos

Pereira

Úbeda

2019

CIG

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High-severity wildfires have a major impact on soil properties. Moreover, recently burned areas are highly sensitive to intense rainfall events. However, little is known about the impact of extreme rainfall on the relationship between soil properties and their spatial distribution. The objective of this study is to examine the effects of an intense rainfall event on soil properties and their spatial distribution in a small area using principal component analysis (PCA). The variables studied were aggregate stability (AS), total nitrogen (TN), soil organic matter (SOM), inorganic carbon (IC), C/N ratio, calcium carbonates (CaCO3), pH, electrical conductivity (EC), available phosphorus (P), extractable calcium (Ca), extractable magnesium (Mg), extractable sodium (Na) and extractable potassium (K). Each PCA (before and after intense rainfall event) allowed us to extract five factors. Factor 1 in the pre-intense rainfall event PCA explained the variance of EC, available P, extractable Mg and K; factor 2 accounted for TN, SOM (high loadings), IC and CaCO3 (low loadings); factor 3 explained AS, extractable Ca and Na; and, factors 4 and 5 accounted for C/N and pH, respectively. Factor 1 in the after intense rainfall event PCA explained the variance of TN, SOM, EC, available P, extractable Mg and K (high loadings) and pH (low loading); factor 2 accounted for IC and CaCO3; factor 3 explained extractable Ca and Na; factor 4 accounted for AS; and, factor 5 for C/N. The results showed that the intense rainfall event changed the relationship between the variables, strengthening the correlation between them, especially in the case of TN, SOM, EC, available P, extractable Mg and extractable Ca with AS. In the case of the pre-intense rainfall event PCA, the best- fit variogram models were: factors 1 and 2 – the linear model; factors 3 and 4 – the pure nugget effect; and, factor 5 – the spherical model. In the case of the factors after intense rainfall event PCA, with the exception of factor 5 (spherical model), the best fit model was the linear model. The PCA score maps illustrated a marked change in the spatial distribution of the variables before and after the intense rainfall event. Important differences were detected in AS, pH, C/N IC, CaCO3, extractable Ca and Na.

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Section: Descriptive Statistics Correlations and Pcasupporting

confidence: 84%

Mapping impact of intense rainfall on a high-severity burned area using principal component analysis

Francos

Pereira

Úbeda

2019

CIG

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“…Previous studies examining the effects of fire on bulk soil chemistry demonstrated that most fire effects on SOM decrease or relax back to preburn conditions on a decadal timescale (Alexis et al, ; González‐Pérez et al, ; López‐Martín et al, ). We find trends in the organic fraction that are consistent with the literature, such as a statistical increase in the lipid fraction of LF‐SOM observed with NMR (González‐Pérez et al, ; López‐Martín et al, ). However, all SOM fractions captured with the molecular mixing model have an elevated fractional uncertainty that persisted during most of the 2 year period (Figure ).…”

Section: Discussionmentioning

confidence: 99%

Short‐Term Changes in Physical and Chemical Properties of Soil Charcoal Support Enhanced Landscape Mobility

et al. 2017

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Charcoal is a major component of the stable soil organic carbon reservoir, and the physical and chemical properties of charcoal can sometimes significantly alter bulk soil properties (e.g., by increasing soil water holding capacity). However, our understanding of the residence time of soil charcoal remains uncertain, with old measured soil charcoal ages in apparent conflict with relatively short modeled and measured residence times. These discrepancies may exist because the fate of charcoal on the landscape is a function not just of its resistance to biological decomposition but also its physical mobility. Mobility may be important in controlling charcoal landscape residence time and may artificially inflate estimates of its degradability, but few studies have examined charcoal vulnerability to physical redistribution. Charcoal landscape redistribution is likely higher than other organic carbon fractions owing to charcoal's low bulk density, typically less than 1.0 g/cm3. Here we examine both the physical and chemical properties of soil and charcoal over a period of two years following a 2011 wildfire in Texas. We find little change in properties with time; however, we find evidence of enhanced mobility of charcoal relative to other forms of soil organic matter. These data add to a growing body of evidence that charcoal is preferentially eroded, offering another explanation for variations observed in its environmental residence times.

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“…The postfire recovery of ρ b has been shown to take 3.3 (Nyman, Sheridan, Smith, & Lane, ) to 7 years (Xue, Li, & Chen, ). Recovery of soil‐organic matter after fire is a longer duration process, with estimates of >5 years (Goudelis, Ganatsas, Tsitsoni, Spanos, & Daskalakou, ), 7 years (López‐Martín, Velasco‐Molina, & Knicker, ), 15–20 years (Kaye, Romanyà, & Vallejo, ), 17 years (Guénon, Vennetier, Dupuy, Ziarelli, & Gros, ), and >20 years (Tessler, Wittenberg, & Greenbaum, ). Both ρ b and soil organic matter do not appear fully recovered to prefire levels at 0–1 cm.…”

Section: Discussionmentioning

confidence: 99%

Thresholds and relations for soil‐hydraulic and soil‐physical properties as a function of burn severity 4 years after the 2011 Las Conchas Fire, New Mexico, USA

Ebel

Romero

Martin³

2018

Hydrological Processes

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Wildfire effects on soil-physical and -hydraulic properties as a function of burn severity are poorly characterized, especially several years after wildfire. A stratified random sampling approach was used in 2015 to sample seven sites representing a spectrum of remotely sensed burn severity in the area impacted by the 2011 Las Conchas Fire in New Mexico, USA. Replicate samples from each site were analysed in the laboratory.Linear and linear indicator regression were used to assess thresholds in soil-physical and -hydraulic properties and functional relations with remotely sensed burn severity.Significant thresholds were present for initial soil-water content (θ i ) at 0-6 cm depth between the change in the Normalized Burn Ratio (dNBR) equal to 618-802, for bulk density (ρ b ) at 3-6 cm between dNBR equal to 416-533, for gravel fraction at 0-1 cm between dNBR equal to 416-533, for fines (the silt + clay fraction) at 0-1 cm for dNBR equal to 416-533, and for fines at 3-6 cm for dNBR equal to 293-416. Significant linear relations with dNBR were present between ρ b at 0-1 cm, loss on ignition (LOI) at 0-1 cm, gravel fraction at 0-1 cm, and the large organic fraction at 1-3 cm.No thresholds or effects on soil-hydraulic properties of field-saturated hydraulic conductivity or sorptivity were observed. These results suggest that ρ b and LOI at 0-1 cm have residual direct impacts from the wildfire heat impulse. The θ i threshold is most likely from delayed groundcover/vegetation recovery that increases evaporation at the highest burn severity sites. Gravel and silt + clay thresholds at 0-1 cm at the transition to high burn severity suggest surface gravel lag development from hydraulic erosion. Thresholds in ρ b from 3 to 6 cm and in silt + clay fraction from 3 to 6 cm appear to be the result of soil variability between sites rather than wildfire impacts.This work suggests that gravel-rich soils may have increased resilience to sustained surface runoff generation and erosion following wildfire, with implications for assessments of postwildfire hydrologic and erosion recovery potential.

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Variability of the quality and quantity of organic matter in soil affected by multiple wildfires

Cited by 24 publications

References 37 publications

Mapping impact of intense rainfall on a high-severity burned area using principal component analysis

Mapping impact of intense rainfall on a high-severity burned area using principal component analysis

Short‐Term Changes in Physical and Chemical Properties of Soil Charcoal Support Enhanced Landscape Mobility

Thresholds and relations for soil‐hydraulic and soil‐physical properties as a function of burn severity 4 years after the 2011 Las Conchas Fire, New Mexico, USA

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