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{"title":"Impact of underground wildfire on plant roots in peat soil","authors":"Yichao Zhang ,&nbsp;Yunzhu Qin ,&nbsp;Yuying Chen ,&nbsp;Shaorun Lin ,&nbsp;Yang Shu ,&nbsp;Xinyan Huang ,&nbsp;Mei Zhou","doi":"10.1016/j.catena.2025.109371","DOIUrl":"10.1016/j.catena.2025.109371","url":null,"abstract":"<div><div>Peatlands are vital terrestrial ecosystems that support a diverse range of plant species and habitats. Wildfire poses a significant disturbance to the peatland ecosystems, especially when underground fires are burning in the peat soil layer. This study presents a comprehensive investigation on the vulnerability of plant root systems to smoldering peat fires through an integrated laboratory and field experiments. In the lab experiments, controlled smoldering fire spreads over peat soil containing simulated plant root samples, that is, wood sticks with diameters of 1–5 cm. In the field experiments, the peat soil planted with larch trees is ignited to observe fire-induced damage to roots. Laboratory experiments show that, when the peat soil moisture content is below 50 % (dry mass basis), almost all root samples burn to ash after the fire, regardless of root diameter within the test range. As peat moisture content increases above 50 %, a greater proportion of the roots remain with different levels of charring and mass loss. Thinner roots experience faster heating and severer damage than thicker roots. The severity of the smoldering peat fires on root is further quantified by relating temperature and heat flux thresholds to residence time, showing long-lasting thermal impacts. The field experiments successfully reveal similar patterns of root charring and damage, deceasing with the soil moisture content. Furthermore, the underground smoldering fire can also initiate a flaming surface fire to exacerbate the fire impact on the root systems. This study quantifies the damage of underground wildfires on plant roots and provides insights into ecological impact and mitigation strategies of the persistent peatland fire and peatland conservation practices.</div></div>","PeriodicalId":9801,"journal":{"name":"Catena","volume":"259 ","pages":"Article 109371"},"PeriodicalIF":5.7,"publicationDate":"2025-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144919810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Climate warming plays an important role in dissolved organic carbon loss in deep soil layers across China","authors":"Lingli Yu ,&nbsp;Mingxu Li ,&nbsp;Xiaoyan Kang ,&nbsp;Li Xu ,&nbsp;Boming Liang ,&nbsp;Jiankun Chen ,&nbsp;Youbin Deng ,&nbsp;Xuanbo Wang ,&nbsp;Xuyang Zhang ,&nbsp;Mengze Qin ,&nbsp;Changhui Peng ,&nbsp;Nianpeng He","doi":"10.1016/j.catena.2025.109404","DOIUrl":"10.1016/j.catena.2025.109404","url":null,"abstract":"<div><div>Dissolved organic carbon (DOC) is one of the most dynamic components of the soil carbon pool. Clarifying its response to climate warming is essential for understanding global carbon cycling processes and predicting future soil carbon pool changes. Using a national database of 4,789 soil DOC profiles covering different soil depths (0–30 cm, 30–100 cm) and ecosystems (forest, grassland, cropland, and wetland), we comprehensively assessed soil DOC content spatiotemporal dynamics across China and the response to climate warming. The results showed significant spatial heterogeneity in the soil DOC of China; high topsoil DOC contents were mainly distributed in low-temperature and dry regions, but high subsoil DOC contents were more concentrated in low-temperature regions. From 1982 to 2020, the topsoil DOC content showed no significant changes (R² = 0.02, <em>p</em> &gt; 0.05), whereas the subsoil DOC content significantly decreased by approximately 4 % (R² = 0.66, <em>p</em> &lt; 0.01). The negative response of the subsoil DOC to temperature was the primary reason for this significant decline. In comparison, the topsoil DOC content remained stable, which could be attributed to the balance between production and consumption. These findings clarify the response patterns of soil DOC to climate warming and indicate that continued DOC reductions could exacerbate soil carbon pool instability and accelerate its feedback effects on climate change.</div></div>","PeriodicalId":9801,"journal":{"name":"Catena","volume":"259 ","pages":"Article 109404"},"PeriodicalIF":5.7,"publicationDate":"2025-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144919707","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The mechanistic role of wildfire ash in regulating post-fire nitrogen transformation: a pathway as critically important as the thermal effects of fire","authors":"Zhaoguo Li ,&nbsp;Md Zahirul Islam ,&nbsp;Guang Yang,&nbsp;Xinyu Wang,&nbsp;Lixuan Wang,&nbsp;Daotong Geng,&nbsp;Jibin Ning","doi":"10.1016/j.catena.2025.109396","DOIUrl":"10.1016/j.catena.2025.109396","url":null,"abstract":"<div><div>Wildfire ash plays a crucial role in mediating post-fire soil nitrogen (N) dynamics; however, the complex mechanisms that connect fuel characteristics, fire behaviors, ash properties, and soil N transformations are not yet fully understood. Wildfire ash samples were obtained by conducting 27 controlled combustion experiments (triple repetition) with different fuel loads (8, 12, and 16 t/ha) and moisture contents (5, 10, 15 %). Subsequently, a 49-day soil incubation experiment with the addition of wildfire ash was carried out. Through this controlled experimental system, we excluded the thermal effects of fire and post-fire erosion to determine the hierarchical impact mechanism of ash on soil N transformations and soil properties.The incorporation of wildfire ash resulted in distinct phases of mineral N dynamics, characterized by a rapid accumulation of NO₃⁻-N within and a concurrent depletion of NH₄⁺-N (7–21 days), contrasting with the delayed nitrification observed in the control samples. These changes were accompanied by transient biogeochemical alterations, including increases in soil pH, electrical conductivity (EC), and soil organic matter (SOM). This suggests that wildfire ash exerts a transient yet significant influence on soil N dynamics and properties, affecting mineral N transformations in a stage-specific manner without disrupting the natural nitrification process of the soil. The redundancy analysis highlighted the intertwined effects of physicochemical and biological regulation among fire, ash, and soil factors. Structural equation modeling revealed hierarchical controls, where fuel characteristics indirectly regulated net N mineralization, nitrification and ammonification via fire behavior and ash properties. This mechanistic framework positions wildfire ash as a biogeochemical engine, reshaping early-phase N transformation through alkali-driven substrate release and nitrifier activation. Our findings advance predictive models of post-fire N fluxes to balance ecosystem recovery with nutrient conservation.</div></div>","PeriodicalId":9801,"journal":{"name":"Catena","volume":"259 ","pages":"Article 109396"},"PeriodicalIF":5.7,"publicationDate":"2025-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144911983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessment and modelling of soil moisture content in silty loess using electrochemical impedance spectroscopy","authors":"Funan Sun ,&nbsp;Bin He ,&nbsp;Pengju Han","doi":"10.1016/j.catena.2025.109408","DOIUrl":"10.1016/j.catena.2025.109408","url":null,"abstract":"<div><div>The structure and stability of silty loess are closely linked to variations in the moisture content and temperature. The advantages of alternating current electrochemical perturbations in capturing high-frequency impedance responses provide comprehensive insights for analysing the interplay between temperature and moisture in silty loess. This study investigates the electrochemical characteristics of silty loess under different temperatures and moisture contents using electrochemical impedance spectroscopy (EIS). Experimental and modelling results revealed that the complex impedance curve of frozen silty loess exhibited distinct electrochemical phenomena: the first capacitive arc in the high-frequency domain corresponded to bound water (near-water layer), whereas the second continuous semi-circular capacitive arc represented free water (far-water layer). The electrochemical characteristics of the silty loess were modelled using an (<em>RC</em>) circuit when the moisture content was below the plastic limit. The electrochemical characteristics were characterised by the dual effect of the (<em>RC</em>)(<em>RC</em>) circuit model in series after freezing, which represents the bound and free water applicable to moisture contents above the plastic limit. The evolution patterns of the equivalent circuit models were identified based on the impedance response over a wide frequency range. A mathematical relationship was established between different moisture content components and electrochemical parameters, expressed as <em>ω</em> = <em>a</em>(ln(<em>R</em>))^-<em>^b</em>. These results improve the understanding of the variation mechanisms in soil moisture through EIS and provide valuable references for further research on the soil electrochemical impedance theory.</div></div>","PeriodicalId":9801,"journal":{"name":"Catena","volume":"259 ","pages":"Article 109408"},"PeriodicalIF":5.7,"publicationDate":"2025-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144911982","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mechanisms underlying the impacts of extreme temperatures on carbon and energy fluxes in dryland ecosystems","authors":"Simin Zhang ,&nbsp;Tingxi Liu ,&nbsp;Limin Duan ,&nbsp;Yongzhi Bao ,&nbsp;Lina Hao ,&nbsp;Xin Tong ,&nbsp;V.P. Singh","doi":"10.1016/j.catena.2025.109401","DOIUrl":"10.1016/j.catena.2025.109401","url":null,"abstract":"<div><div>Under global climate change, the increasing frequency and intensity of extreme temperature events have significantly affected carbon and energy fluxes in dryland ecosystems. However, the underlying response mechanisms and the regulatory role of water availability remain insufficiently quantified. Based on long-term growing-season observations (2013–2024) in the Horqin Sandy Land, this study quantitatively characterized the impacts of extreme low-temperature (ELT) and extreme high-temperature (EHT) events on carbon (NEE, Reco, GPP) and energy (Rn, LE, H) fluxes in dune and meadow ecosystems, from the dual perspectives of flux anomalies and change rates, while incorporating soil moisture gradients (VWC ± ). The results showed that during the study period, EHT&amp;VWC + events increased significantly (by 65 % in dunes and 37 % in meadows), while ELT&amp;VWC − events sharply declined (by 89 % in dunes and 63 % in meadows). Carbon fluxes in dunes were highly sensitive to soil moisture conditions, with drought-induced carbon release reversible to a carbon sink upon water supplementation. In contrast, meadows exhibited stronger temperature adaptability, maintaining a stable carbon sink function (−0.20/-0.25 g C m^–2d^–1) under high-temperature drought regardless of soil water variation, likely due to their deeper root systems and higher evaporative cooling capacity, which buffer heat stress and sustain photosynthetic activity. The two ecosystems exhibited distinct energy allocation strategies: dunes dissipated energy primarily by enhancing sensible heat flux (H sensitivity = 0.90), whereas meadows prioritized the regulation of latent heat flux (LE sensitivity = 0.84). This study proposed an “event frequency–water regulation–flux response” framework, which provided methodological support and empirical basis for the resilience assessment of dryland ecosystems to climate extremes and the optimization of management strategies.</div></div>","PeriodicalId":9801,"journal":{"name":"Catena","volume":"259 ","pages":"Article 109401"},"PeriodicalIF":5.7,"publicationDate":"2025-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144907434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Distribution of arsenic concentrations in soils historically impacted by mining activities: Cross-validation of pXRF methodology and application to the Orbiel valley (France)","authors":"Marie Heydon ,&nbsp;Magali Philippe ,&nbsp;Jean-Marc Antoine ,&nbsp;Jérôme Viers ,&nbsp;Aude Calas ,&nbsp;François Aussaguel ,&nbsp;Rémi Freydier ,&nbsp;Mylène Marie ,&nbsp;Philippe Behra ,&nbsp;Eva Schreck","doi":"10.1016/j.catena.2025.109389","DOIUrl":"10.1016/j.catena.2025.109389","url":null,"abstract":"<div><div>Understanding contaminant distribution in industrial and mining areas is essential for protecting human health and the environment, although traditional mapping methods are costly and time-consuming. This study aims to provide, using portable X-ray fluorescence (pXRF), rigorous maps of soil As concentrations over the Orbiel valley, historically impacted by mining activities since several decades. After a cross-calibration of pXRF with ICP-MS, we mapped As distribution in topsoils, and investigated factors influencing As dispersion. Two field campaigns were conducted: one targeting riverbanks and floodplains, the other on a 1 x 1 km grid over a 10 km radius from pollution sources. Spatial mapping identified three zones with high As concentrations (193–342 mg kg⁻¹), exceeding background levels (44 mg kg⁻¹), with floodplains particularly impacted (178 mg kg⁻¹), likely due to transport processes. Our findings confirm pXRF as a powerful tool for rapid, high-resolution As contamination screening in post-mining contexts. Cross-calibration showed no significant differences between pXRF and ICP-MS (Kruskal-Wallis, p &gt; 0.05) and strong correlations (Pearson R &gt; 0.90). Optimal pXRF modes (Soil, TestAllGeo and Mining modes) ensured accurate measurements of As, Pb, Mn, and Zn. Finally, the maps of As distribution over the valley, as well as Pb isotopic data in the different environmental compartments, suggest both a local origin of this contamination and the influence of rivers but above all atmosphere in As dispersion.</div></div>","PeriodicalId":9801,"journal":{"name":"Catena","volume":"259 ","pages":"Article 109389"},"PeriodicalIF":5.7,"publicationDate":"2025-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144903751","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of waste-derived synthetic zeolite on soil hydraulic properties and soil water storage parameters in sandy-loam soils","authors":"Antonio Satriani ,&nbsp;Stella Lovelli ,&nbsp;Claudia Belviso ,&nbsp;Alessandro Comegna","doi":"10.1016/j.catena.2025.109395","DOIUrl":"10.1016/j.catena.2025.109395","url":null,"abstract":"<div><div>Zeolites are used in agriculture to amend soil chemical and physical properties. They have complex internal frameworks that enable them to alter soil texture and structure, with a direct influence on the soil’s hydrological behavior, enabling better control of groundwater contamination and more efficient irrigation management practices. This ability provides opportunities to optimize water and solute movement in coarse-textured soils while enhancing nutrient availability due to their high cation exchange capacity and water retention. In this study, a series of laboratory experiments were conducted on sandy-loam soils with different pedological characteristics, mixed with a synthetic zeolite derived from fly ash, a byproduct of coal combustion. Repacked soil samples were amended with three different zeolite concentrations (2 %, 5 %, and 10 % by weight) and subsequently analyzed for their hydraulic properties and soil water storage parameters (SWSPs) of agronomic interest. Consistent with recent research findings, our results indicate that zeolite influences soil pore-size distribution. Specifically, total soil porosity increased, with mesoporosity and microporosity rising by approximately 11% and 13%, respectively. The effects induced by zeolite showed a direct correlation with the selected soil hydraulic properties and SWSPs. Our study shows that in coarse-textured soils, incorporating an appropriate dose of zeolite enhances water retention within the soil profile while preventing excessive saturation in the root zone.</div></div>","PeriodicalId":9801,"journal":{"name":"Catena","volume":"259 ","pages":"Article 109395"},"PeriodicalIF":5.7,"publicationDate":"2025-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144907432","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Shallow-depth hardpan attributes influence soil surface and subsurface hydraulic properties","authors":"N.R.R.W.S. Rathnayake ,&nbsp;D.A.L. Leelamanie ,&nbsp;Morihiro Maeda","doi":"10.1016/j.catena.2025.109405","DOIUrl":"10.1016/j.catena.2025.109405","url":null,"abstract":"<div><div>Hardpan development is a crucial factor in determining soil hydraulic properties. Information lacks on how shallow-depth thin hardpans of a few centimeters influence soil surface and subsurface hydraulic properties. The present study aimed to assess effects of thickness of hardpan (THP<span><span>¹</span></span>), (1.7 g cm⁻³ bulk density) and depth to the hardpan (DHP<span><span>²</span></span>) on initial infiltration rate (<em>I</em>_i), unsaturated hydraulic conductivity (<em>K</em>), sorptivity (<em>S</em>_W), and steady-state infiltration rate (<em>I</em>_SS). Three THP levels (1 cm: THP_1, 3 cm: THP₃, 5 cm: THP₅) and four DHP levels (0 cm: DHP₀, 1 cm: DHP₁, 3 cm: DHP₃, 5 cm: DHP₅) were tested in the experiment with a control (no hardpan) in prepared soil columns. Soil hydraulic properties were measured using a Mini disk infiltrometer. All soil columns with hardpans showed significantly lower <em>I</em>_i, <em>K</em>_, <em>S</em>_W, and <em>I</em>_SS compared with the control (<em>p</em> &lt; 0.05). Surface hardpan (DHP₀) revealed &gt;90 % decline in <em>I</em>_i, <em>K</em>_, and <em>S</em>_W compared with the control. At DHP₁, <em>I</em>_i, <em>K</em>, <em>S</em>_W, and <em>I</em>_SS showed 19–44 %, 71–95 %, 43–57 %, and 50–70 % reductions, respectively, at the three thickness levels compared with the control. As DHP increased (DHP₃, DHP₅), the percentage declines of these parameters gradually decreased, showing their values closer to control at DHP₅. Hardpans with 1 cm thickness showed an increase in cumulative infiltration after ∼60 s stagnant period, suggesting a potential for water flow to pass through the hardpan. The <em>I</em>_i showed strong positive linear correlations with <em>S</em>_W and <em>K</em> confirming that impeded surface water-entry not only influences surface water absorption, but also influences water movements within the soil. Present study further confirms that both surface and subsurface hydraulic properties can be detrimentally affected as a result of diminished pore geometry due to shallow-depth hardpans. Further experiments are required to explore the effects of shallow-depth hardpans on soil hydraulic properties with different soil types.</div></div>","PeriodicalId":9801,"journal":{"name":"Catena","volume":"259 ","pages":"Article 109405"},"PeriodicalIF":5.7,"publicationDate":"2025-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144903653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The contributions of climate, permafrost, and snow factors to vegetation change in northern hemisphere permafrost regions","authors":"Xiaoqing Peng ,&nbsp;Yaohua Zhao ,&nbsp;Oliver W. Frauenfeld ,&nbsp;Panpan Wang ,&nbsp;Gubu Qiumo ,&nbsp;Chen Yang ,&nbsp;Hengxing Luo ,&nbsp;Qian Li ,&nbsp;Qinshan Zhao ,&nbsp;Lili Li ,&nbsp;Jia Sui","doi":"10.1016/j.catena.2025.109397","DOIUrl":"10.1016/j.catena.2025.109397","url":null,"abstract":"<div><div>Northern permafrost regions are experiencing a warming trend, leading to permafrost degradation and changes in snow cover. Concurrently, vegetation is generally greening, primarily attributed to climatic factors such as air temperature. However, the contributions of permafrost (active layer thickness, ALT) and snow (earlier snow onset, SOM) to vegetation changes remain unclear. For 2001–2021, we therefore determine the start of the growing season (SOS), the end of the growing season (EOS), and the annual maximum normalized difference vegetation index (MaxNDVI) as indicators of vegetation growth. We also chose representative factors for climate, permafrost, and snow. The results indicate an earlier soil thaw start date (SOT) and a deepening of the ALT promoted the earlier SOS and the increase in MaxNDVI. SOM also facilitated the earlier SOS, while also affecting MaxNDVI. Increased snow depth positively influenced vegetation growth in some areas. From 2001 to 2021, the average contribution of climate, permafrost, and snow factors to vegetation changes ranged 61–72 %, 15–25 %, and 12–14 %, respectively. Climatic factors remained the dominant drivers of vegetation change, followed by permafrost. For SOS, SOT and ALT exhibited positive and negative influences, respectively. For EOS, changes in ALT showed a negative influence, indicating that continued deepening of ALT may hinder the delay of EOS and shorten the growing season. Snow cover had a far smaller influence on vegetation changes compared to climate. This study represents the first attempt to quantify the contributions of climate, permafrost, and snow to vegetation changes in northern permafrost regions, providing new insights and laying the groundwork for future research.</div></div>","PeriodicalId":9801,"journal":{"name":"Catena","volume":"259 ","pages":"Article 109397"},"PeriodicalIF":5.7,"publicationDate":"2025-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144903654","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High-severity fire reduces soil erosion resistance: A study based on 4-year field monitoring data in dry-warm valley in Southwest China","authors":"Xiaosong Qin ,&nbsp;Yi Wang ,&nbsp;Longxi Cao ,&nbsp;Ping Ren ,&nbsp;Wei He ,&nbsp;Yongkang Li ,&nbsp;Dongdong Hou ,&nbsp;Yufan Wang ,&nbsp;Jia Xu","doi":"10.1016/j.catena.2025.109400","DOIUrl":"10.1016/j.catena.2025.109400","url":null,"abstract":"<div><div>Forest fire has occurred frequently in the dry-warm valley of Southwest China in recent years. Fire changes physicochemical properties, which may further affect soil erosion resistance (rill erodibility (<em>K_r</em>) and critical shear stress(<em>τ_c</em>)). However, few studies have examined the effects of high-severity fire on <em>K_r</em> and <em>τ_c</em> and the temporal variation characteristics. To evaluate the temporal variation in <em>K_r</em> and <em>τ_c</em> and the influencing factors after high-severity fire, soil samples were collected from burned areas 0.5, 1, 2 and 3 years after the fire, and from unburned areas. Then, <em>K_r</em> and <em>τ_c</em> were determined via a flume experiment at three slopes (17.6, 36.3 and 57.7 %) and five flow discharges (0.8, 1.6, 2.4, 3.2 and 4.0 L s⁻¹). The results revealed that <em>K_r</em> and <em>τ_c</em> varied in the ranges of 0.0006–0.0013 s m⁻¹ and 0.8144–2.2584 Pa, respectively. Compared with the unburned areas, the burned areas presented an increase in <em>K_r</em> of 20 %–160 % and a decrease in <em>τ_c</em> of 37.29 %–77.39 %. With the prolonging of restoration years, <em>K_r</em> gradually decreased and <em>τ_c</em> gradually increased, but it was still lower than the level in unburned areas. Correlation analysis and structural equation modeling showed that median soil particle size (total effects of 0.49 and −0.27, respectively, <em>p</em> &lt; 0.05) and soil organic matter (total effects of −0.71 and 0.90, respectively, <em>p</em> &lt; 0.05) were the most significant factors affecting <em>K_r</em> and <em>τ_c</em> during the 0.5–3 years experiment post-fire. <em>K_r</em> (<em>R²</em> = 0.613, <em>NSE</em> = 0.582) and <em>τ_c</em> (<em>R²</em> = 0.974, <em>NSE</em> = 0.974) could be well estimated by bulk density, median soil particle size, root mass density, soil shear strength, soil organic matter and recovery time. These results provide new insights into the mechanism of the influence of post-fire on soil erosion resistance in the dry-warm valley.</div></div>","PeriodicalId":9801,"journal":{"name":"Catena","volume":"259 ","pages":"Article 109400"},"PeriodicalIF":5.7,"publicationDate":"2025-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144894987","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}