Differential thermal resistance of Andisols and Inceptisols under fire heating: the role of short-range-order minerals

Published: 10 October 2025| Version 1 | DOI: 10.17632/43k3fv9f39.1
Contributor:
Carolina Merino

Description

This dataset contains experimental and derived variables from a single-pulse heating test (20 min) applied to two temperate forest soils from southern Chile: a volcanic Andisol and a granodioritic Inceptisol. Each soil includes a control at 25 °C and three temperature plateaus (300, 600, 900 °C) with n = 4 replicates per combination (total 32 observations). Data are provided in wide format with a companion README. Variables (columns) • Identifiers: Soil (Andisol/Inceptisol), Temperature_C (25/300/600/900), Replicate (1–4). • Residuals (% of the soil-specific control, 25 °C): SOC_resid_pct, N_resid_pct. • Absolute contents (g kg⁻¹): SOC_abs_gkg, N_abs_gkg (computed from baseline × residual). • Chemistry: pH (H₂O 1:2.5), ECEC_umolc_g (NH₄OAc 1 M pH 7 + KCl 1 M). • Selective dissolutions (% of control): Feo_pct_control, Alo_pct_control, Alp_pct_control (oxalate and pyrophosphate pools); Fed_pct_control (dithionite–citrate); Sio_pct_control, Sid_pct_control; Mno_pct_control, Mnd_pct_control, Mnp_pct_control. • Derived indices: Allophane_proxy = (Alo − Alp)/Sio (dimensionless using % units), Mn_oxidation_index = Mnd/(Mno + Mnp). • XRD (relative indices): XRD_Allo_index (allophane halo, 0–1), XRD_HM_index (hematite/magnetite, 0–1). • DLS (dispersion): Zavg_um (Z-average, µm), PdI (0–1). • TGA/DSC–MS: mass_resid_pct (residual mass %), Volatile_class (CO₂/N₂O at 300 °C; aromatics or carboxyl/amide at 600–900 °C). Methods (overview) Static furnace heating (20 min) at 300–900 °C; dry combustion for C and N; pH and ECEC by standard procedures; selective extractions (oxalate, pyrophosphate, dithionite–citrate) quantified by AAS; powder XRD (2–60° 2θ, 0.01°) with relative indices; DLS on <53 µm fraction (0.01 M NaCl, 25 °C, backscatter 173°); STA-TGA/DSC (25–900 °C, 10 °C min⁻¹, dry air 40 mL min⁻¹) coupled to GC–MS for volatile classes. Authorship (CRediT, brief) Conceptualization/Supervision: C. Merino, F. Matus. Investigation/Data curation: K. Erazo, N. Zumelzu, I. Jofré. Methodology/Resources: F. Nájera, F. Aburto, P. Durán, J. Dörner. Formal analysis/Visualization: C. Merino, K. Erazo, M. A. Dippold. Writing: all authors.

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Steps to reproduce

1. Sampling (0–5 cm): volcanic Andisol (Tolhuaca NP) and granodioritic Inceptisol (Nahuelbuta NP). Composite of four field subsamples per site; cooled transport, air-dry, sieve < 2 mm. 2. Heating: muffle furnace at 300/600/900 °C for 20 min (control 25 °C). Pre-equilibrate to setpoint; start timing after recovery (< 3 min). 3. C and N: dry combustion (Dumas). pH in water (1:2.5). ECEC = sum of exchangeable cations (NH₄OAc 1 M pH 7) + exchangeable Al³⁺ (KCl 1 M). 4. Selective extractions: oxalate 0.2 M pH 3 (in the dark) for Alo, Feo, Mno, Sio; pyrophosphate 0.1 M for Alp, Fep, Mnp; dithionite–citrate for Fed, Mnd, Sid. Quantify by AAS. 5. XRD: CuKα, 2–60° 2θ, 0.01°; compute relative indices XRD_Allo_index and XRD_HM_index. 6. DLS: < 53 µm fraction in 0.01 M NaCl; ultrasonication 15 min; non-invasive backscatter 173° at 25 °C; report Zavg_um and PdI. 7. TGA/DSC–MS: 25–900 °C, 10 °C min⁻¹, dry air 40 mL min⁻¹; GC–MS library matching for Volatile_class; record mass_resid_pct. 8. Derivations: residuals (%) relative to each soil’s control (25 °C); Allophane_proxy = (Alo − Alp)/Sio; Mn_oxidation_index = Mnd/(Mno + Mnp); absolute C and N from baseline × residual. 9. Statistics (example): normality (Shapiro–Wilk) and homoscedasticity (Levene); one-way ANOVA within soil across temperatures (α = 0.05) + Tukey; if violated, Kruskal–Wallis + Dunn–Holm; PCA with prcomp(scale=TRUE). 10. Reproducibility: see the README sheet for column definitions, units, and limits.

Institutions

  • Universidad de La Frontera

Categories

Soil Science, Geochemistry

Funders

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