Unveiling soil temperature reached during a wildfire event using ex-post chemical and hydraulic soil analysis.

Autor: Martínez SI; Departamento de Ingeniería Hidráulica y Ambiental, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, Macul, Santiago 7820436, Chile., Contreras CP; Departamento de Ingeniería Hidráulica y Ambiental, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, Macul, Santiago 7820436, Chile., Acevedo SE; Departamento de Ingeniería Hidráulica y Ambiental, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, Macul, Santiago 7820436, Chile., Bonilla CA; Departamento de Ingeniería Hidráulica y Ambiental, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, Macul, Santiago 7820436, Chile; Centro de Desarrollo Urbano Sustentable ANID/FONDAP/15110020, El Comendador 1916, Providencia, Santiago 7520245, Chile. Electronic address: cbonilla@ing.puc.cl.
Jazyk: angličtina
Zdroj: The Science of the total environment [Sci Total Environ] 2022 May 20; Vol. 822, pp. 153654. Date of Electronic Publication: 2022 Feb 04.
DOI: 10.1016/j.scitotenv.2022.153654
Abstrakt: Wildfires affect different physical, chemical, and hydraulic soil properties, and the magnitude of their effects varies depending on intrinsic soil properties and wildfire characteristics. As a result of climate change, the frequency and intensity of wildfires have increased, and understanding their impact and predicting the temperature to which soils were exposed in previous events is becoming increasingly critical. Hence, the objectives of this study were to develop a soil-heating laboratory procedure to (a) identify changes in soil properties at different temperatures and (b) to infer the temperature ranges to which heated soils have been exposed. Saturated (K s ) and unsaturated (K u ) hydraulic conductivity, pH, electrical conductivity (EC), wet aggregate stability (WAS), soil water repellency index (RI m ), and soil organic matter content (SOM) were measured in six laboratory heated (LH) soils at 300, 500, 700, and 900 °C for 2 h. Bulk density (BD) and soil texture were measured in unheated (UH) and wildfire-unheated (WH) samples. UH samples were used as baselines to quantify changes in soil properties, and WH and LH samples were compared to determine the temperatures to which WH soils were exposed. The results show that in the studied temperature range, WAS exhibited a U-shaped trend, opposite to that of pH and EC. Ks and Ku (negative tension of -3 cm) tend to increase with temperature, reaching a maximum of 1.27·10-4 and 5.62·10-5 (m/s) at 900 °C, respectively. RIm was highly dependent on texture; loam soils had an average minimum and maximum of 1.84 and 2.73, at 900 and 300 °C, respectively, while sandy loam soils had an average minimum and maximum of 1.29 and 2.08 at 300 and 900 °C, respectively. Finally, the parameters that provided laboratory variation and a temperature range consistent with the results observed in naturally heated soils were WAS, RI m , pH, and EC.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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