GeodermaPub Date : 2025-10-01DOI: 10.1016/j.geoderma.2025.117524
Lixing Zhang , Dapeng Yue , Jingbo Zhao , Xiaoning Wang , Yueshan Liu , Lili Yang
{"title":"Evolution of millennial-scale sandy land’s advance and retreat in the Chinese sand-loess belt since 150 ka","authors":"Lixing Zhang , Dapeng Yue , Jingbo Zhao , Xiaoning Wang , Yueshan Liu , Lili Yang","doi":"10.1016/j.geoderma.2025.117524","DOIUrl":"10.1016/j.geoderma.2025.117524","url":null,"abstract":"<div><div>Understanding the evolution of aeolian activities and the changes in desert/sand environments is crucial for clarifying their occurrence mechanisms and promoting ecological restoration. Although evidence from loess and lake records in the Chinese sand-loess belt has shown the role of the East Asian winter monsoon (EAWM) in duststorm activities, these records can’t clearly divide the intensity grades and shifts in material components nor explain the mechanism. This study used grain size, magnetic susceptibility (MS), and the SiO<sub>2</sub>/Al<sub>2</sub>O<sub>3</sub> ratio analyses, along with the grain size end-member (EM) model, fractal dimension (Dv), and MS-based paleo-precipitation reconstruction to clarify these aspects. Four grain size end-members (EMs) revealed that fine grains were predominantly derived from westerly wind and pedogenesis, while the EAWM primarily transported coarse grains. We classified aeolian activity intensity into three grades based on changes in the proportion of sand, which were the main signs of intense wind erosion in the LHG profile located in the southeastern margin of the Mu Us Sandy Land (MUSL). Since 150 ka, there have been three major episodes of sand expansion and three fixed or shrinking intervals. It was mostly a sand environment, except during the early L<sub>1</sub>F phase when it became a typical desert environment with mean annual precipitation (MAP) of 164.49 mm. Desert/sand evolution was constrained by moisture, vegetation, and wind field conditions. These factors were driven jointly by solar insolation and ice sheet dynamics, and synchronized recorded glacial-interglacial and millennial-scale oscillations. The findings help improve our knowledge of regional ecological environment changes and aeolian disaster monitoring and prevention.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"462 ","pages":"Article 117524"},"PeriodicalIF":6.6,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145183077","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}
GeodermaPub Date : 2025-10-01DOI: 10.1016/j.geoderma.2025.117522
Jonti Evan Shepherd, Ori Kanner, Or Amir, Keren Ben-Zion, Eyal Ben-Dor
{"title":"Rapid retrieval of soil surface aggregation as a joint attribute to soil spectral libraries","authors":"Jonti Evan Shepherd, Ori Kanner, Or Amir, Keren Ben-Zion, Eyal Ben-Dor","doi":"10.1016/j.geoderma.2025.117522","DOIUrl":"10.1016/j.geoderma.2025.117522","url":null,"abstract":"<div><div>Utilizing Soil Spectral Libraries (SSLs) enables rapid, non-destructive, predictions of soil attributes by linking wet-chemistry data with the reflectance spectra of air-dried, <2 mm soil samples. However, the influence of surface aggregation on the light-scattering behavior of soil is generally overlooked primarily due to the complexity of its measurement, although it remains a key physical chromophore for databases. Yet, because surface aggregation can significantly affect spectral responses, particularly through its impact on scattering, it may represent a critically important parameter. Here, we present a novel, scalable and easy method combining USB-microscope RGB imaging and segmentation of the surface soil grains using the Segment Anything Model (SAM, ViT-H) a promotable, zero-shot vision transformer that infers surface aggregate size sensu strictu (<250 µm) distributions immediately prior to spectral measurement. Ninety-one air dried soils representing six USDA soil orders were sieved to <2 mm, imaged in five replicates under controlled illumination, and physically fractionated via quantitative laboratory-based sieving into six size classes (<0.1 mm to 2 mm) to compute gravimetric average aggregate diameter (AVG). RGB images acquired through a USB-microscope were segmented, filtered by contour properties, and particle diameters extracted via Feret diameter; aggregates <0.10 mm (derived from a measured µm px<sup>−1</sup>) were excluded. Mean, percentile, and error metrics were calculated per soil type. Correlation between digitally inferred RGB and gravimetrically laboratory derived aggregate diameters was strong (R<sup>2</sup> = 0.70, RMSE = 0.111, MAE = 0.091), with particularly robust performance in sandy and loamy soils, while clay-rich soils exhibited deeper subsurface heterogeneity. These results suggest that spectral standard deviation (SD) and variation in spectral replications of clayey soils may be higher than in sandy and silty soils which arises from the irregularly of the soil grain size, signaling to take precaution. Multi-angle imaging with increased replications aligns with standard spectroradiometer protocols and can be integrated into SSL curation pipelines. Both the physical and digital analyses of the soil’s grain size represent spectral correlation with the main cementation agents in the soil: Clay and SOM content. By embedding surface aggregation into SSLs, this method enhances the physical realism of proximal-sensing models, offering a cost-effective, time-efficient alternative to traditional physical sieving and advancing both laboratory and potential in-situ soil assessments.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"462 ","pages":"Article 117522"},"PeriodicalIF":6.6,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145183200","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}
GeodermaPub Date : 2025-10-01DOI: 10.1016/j.geoderma.2025.117531
Junru Chen , Shuna Feng , Miles Dyck , Francis Zvomuya , Xiaobin Li , Hailong He
{"title":"A COMSOL-based numerical approach to improve heat-pulse measured frozen soil thermal properties","authors":"Junru Chen , Shuna Feng , Miles Dyck , Francis Zvomuya , Xiaobin Li , Hailong He","doi":"10.1016/j.geoderma.2025.117531","DOIUrl":"10.1016/j.geoderma.2025.117531","url":null,"abstract":"<div><div>Heat pulse (HP) is the most widely used transient technique determining soil thermal properties (STPs) in unfrozen conditions, yet its application to frozen soils introduces significant challenges. At high subfreezing temperatures (−5 to 0 °C), the HP measurements induce thawing and refreezing of ice, dynamically altering the frozen soil thermal properties (FSTPs) being measured. Conventional analytical solutions fail to account for these phase change effects, leading to substantial errors in estimation. Although various approaches have been developed to improve FSTPs determination, achieving accurate measurements remain challenging. This study employed a COMSOL-based numerical model to solve heat conduction equations incorporating latent heat and compared the results with that obtained with traditional analytical solutions. The results revealed that analytical solutions consistently underestimate frozen soil thermal conductivity (FSTC) at temperatures above −3 °C, even with optimized heating strategies. Numerical simulations demonstrated that phase transition parameters critically influence temperature evolution, particularly above −5 °C, and the COMSOL improved FSTC estimates between −4 and 0 °C, though the performance depended on heating strategies. To facilitate parameter selection, linear regression models were derived for phase transition interval (Δ<em>T<sub>p</sub></em>, <em>R</em><sup>2</sup> = 0.37) and phase transition point (<em>T<sub>pc</sub></em>, <em>R</em><sup>2</sup> = 0.30). These advancements enhance the accuracy of HP-measured FSTPs, providing a more reliable approach for cold-region researches and applications.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"462 ","pages":"Article 117531"},"PeriodicalIF":6.6,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145268385","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}
GeodermaPub Date : 2025-10-01DOI: 10.1016/j.geoderma.2025.117549
Hyojung Ko , Heerym Han , Hyunwook Choo
{"title":"Effect of degree of saturation on the electrical conductivity of soils: role of surface conduction","authors":"Hyojung Ko , Heerym Han , Hyunwook Choo","doi":"10.1016/j.geoderma.2025.117549","DOIUrl":"10.1016/j.geoderma.2025.117549","url":null,"abstract":"<div><div>The estimation of the degree of saturation (<em>S</em>) based on electrical conductivity, <em>σ<sub>mix</sub></em> (or electrical resistivity) surveys typically relies on the <em>S</em>-exponent of Archie’s equation. However, the <em>S</em>-exponent varies with soil type, indicating significant variability and the potential for miscalculation of <em>S</em>. This study focuses on the variability of the <em>S</em>-exponent in Archie’s equation across soil types and investigates the relationship between <em>σ<sub>mix</sub></em> and <em>S</em> in terms of pore water conduction (<em>K<sub>w</sub></em>) and surface conduction (<em>K<sub>s</sub></em>) through theoretical modeling and experimentation. Silica sand and two types of clays were tested at various initial porosities and pore water concentrations, and <em>σ<sub>mix</sub></em> was measured over a range of <em>S</em> values (20% to 100%). For sand, where surface conduction is negligible, Archie’s equation with a constant <em>S</em>-exponent (approximately 2) accurately predicted <em>σ<sub>mix</sub></em>. However, clays exhibited varying <em>S</em>-exponents, ranging from 1.5 to 2.1, depending on pore water conductivity. This suggests that a new model is needed to accurately predict <em>σ<sub>mix</sub></em> in unsaturated clayey soils. A newly proposed <em>σ<sub>mix</sub></em> estimation formula, incorporating separate <em>S</em>-exponents for <em>K<sub>w</sub></em> and <em>K<sub>s</sub></em>, provided accurate predictions across various test conditions. These findings enhance the understanding of electrical conductivity in unsaturated soils and offer a simple yet effective model for its prediction.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"462 ","pages":"Article 117549"},"PeriodicalIF":6.6,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145311721","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}
GeodermaPub Date : 2025-10-01DOI: 10.1016/j.geoderma.2025.117515
Anil C. Somenahally , Laxman Bokati , Saurav Kumar
{"title":"Estimating soil organic carbon deficits at the continental scale using legacy-data-driven dynamic baseline and attainable projections","authors":"Anil C. Somenahally , Laxman Bokati , Saurav Kumar","doi":"10.1016/j.geoderma.2025.117515","DOIUrl":"10.1016/j.geoderma.2025.117515","url":null,"abstract":"<div><div>Soil organic carbon (SOC) stocks vary temporally, across land use, climate, and soil type, making it challenging to model current stocks (SOC<sub>cs</sub>). The attainable steady-state stock (SOC<sub>at</sub>), the practically achievable under optimal soil, climate, and management conditions, remains dynamic because soil-loss processes continually modify the biophysical limits on maximum storage, causing SOC<sub>at</sub> to shift over time. Robust methods are required to integrate temporal dynamics, model and extrapolate SOC<sub>cs</sub> and SOC<sub>at</sub>, and quantify current deficits (SOC<sub>def</sub>), the unrealized sequestration capacity. We used legacy SOC observations along with time-adjustment and data-driven modeling to generate spatially explicit projections of 2024 SOC<sub>cs</sub>. We estimated SOC<sub>at</sub> by selecting the maximum SOC value from a spatially constrained similarity matrix of projected SOC<sub>cs</sub>, then used both reference layers to derive location-specific SOC<sub>def</sub>. The resulting maps revealed extensive heterogeneity among the land use types and across regions. Mean SOC<sub>def</sub> of 3.46 kg m<sup>–2</sup> was noted for all croplands in continental United States. Larger deficits clustered on soil orders of Mollisols and Alfisols in the Midwest region, but were lower than anticipated, alluding to depleted SOC<sub>cs</sub> and SOC<sub>at</sub>. Degraded grasslands showed similarly reduced SOC<sub>at</sub>, underscoring the need to recalibrate sequestration targets based on current projected steady states. The results underscore the framework’s novelty as it effectively integrates temporal dynamics of soil carbon stocks and converts soil-carbon storage processes into actionable, farm-level sequestration targets. By generating empirically derived, region-specific SOC<sub>cs</sub>–SOC<sub>at</sub>–SOC<sub>def</sub> benchmarks, the framework offers precise reference points that align management incentives, climate-smart policies, and site-specific restoration strategies.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"462 ","pages":"Article 117515"},"PeriodicalIF":6.6,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145217804","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}
GeodermaPub Date : 2025-10-01DOI: 10.1016/j.geoderma.2025.117539
Lin Liu , Xiaoting Xie , Yili Lu , Tusheng Ren
{"title":"A new approach for estimating pore water electrical conductivity of saturated soils","authors":"Lin Liu , Xiaoting Xie , Yili Lu , Tusheng Ren","doi":"10.1016/j.geoderma.2025.117539","DOIUrl":"10.1016/j.geoderma.2025.117539","url":null,"abstract":"<div><div>Soil salinity is commonly assessed by measuring the electrical conductivity of the soil saturated paste extract, i.e., pore-water electrical conductivity of saturated soils (σ<sub>ps</sub>), yet its accurate determination remains challenging. While Hilhorst (2000) established a linear relationship between bulk soil electrical conductivity (σ) and dielectric constant (<em>K</em><sub>a</sub>) using σ<sub>ps</sub> as a parameter, its applicability across diverse soil textures requires further examination. The objectives of this study are to evaluate the σ-<em>K</em><sub>a</sub> relationship for σ<sub>ps</sub> estimation σ<sub>ps</sub> across a broad texture spectrum, and to develop a generalized relationship between the formation factor (<em>F</em><sub>s</sub>, the ratio of pore-water electrical conductivity σ<sub>p</sub> and σ) and porosity (<em>n</em>) for σ<sub>ps</sub> estimation at room temperature (25 ± 1 °C). The model was validated using independent datasets spanning clay content from 0 to 0.47 g g<sup>−1</sup> and σ<sub>ps</sub> values from 0 to 20 dS m<sup>−1</sup>. Comparing to exiting methods, the new approach achieved superior performance with an average root mean square error of 0.44 dS m<sup>−1</sup>. The proposed method enables reliable σ<sub>ps</sub> estimation using only <em>n</em> and saturated bulk electrical conductivity measurements, offering practical advantages for field-scale soil salinity monitoring.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"462 ","pages":"Article 117539"},"PeriodicalIF":6.6,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145268364","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}
GeodermaPub Date : 2025-10-01DOI: 10.1016/j.geoderma.2025.117504
T.S. Breure , R. Webster , S.M. Haefele , J.A. Hannam , R. Corstanje , A.E. Milne
{"title":"The effect of uncertainty in predictions of nutrient concentrations from soil spectra on variable-rate fertilizer applications","authors":"T.S. Breure , R. Webster , S.M. Haefele , J.A. Hannam , R. Corstanje , A.E. Milne","doi":"10.1016/j.geoderma.2025.117504","DOIUrl":"10.1016/j.geoderma.2025.117504","url":null,"abstract":"<div><div>The concentrations of available phosphorus (P) and potassium (K) in soil can be estimated by soil spectroscopy, and with sufficient sampling can be mapped to guide farmers to apply fertilizer at variable rates. Mapping errors arise from both spatial variation and calibration of the spectra against chemically determined concentrations. We aimed to develop a loss-function framework to explore how sizes of sample sets and calibration sets affect the likely profitability of variable-rate applications of P and K fertilizers. We demonstrate the approach through simulation. Based on our previous observations of variation in P and K from four fields in Cambridgeshire, England, we generated 100 realizations of P and K in each field using geostatistical simulation. We did so with various combinations of sizes of total sample and calibration set. For each such sample we assigned various proportions for calibration on which notionally both soil spectroscopy and chemical concentrations were determined. Knowing the costs for labour in the field for sampling, the preparation of soil in the laboratory, the spectroscopy, chemical analysis and amortization of equipment, we estimated the costs of acquiring data. Set against these were the costs of error, i.e. of uncertainty, in the final predictions by kriging arising from calibration error and spatial variation. For each combination we computed the fertilizer required to minimize the expected loss associated with predictions, where the expected loss is the difference in profit between applying fertilizer for the estimated concentrations of P and K and their true concentrations. The size of the calibration set outweighed the effect of total sample size on the uncertainty associated with predictions. Equally, for the same size of calibration set, there were large differences in the kriging variances between total sample sizes. When the costs of acquiring data were disregarded, the expected loss for available P was strongly affected by the total sample size. For available K, the effect of the size of the calibration sample dominated the expected loss. The expected loss showed diminishing returns with increasing sample size. None of the sample sizes considered would result in a financial gain: spectroscopy needs to become cheaper for it to be cost-effective for variable-rate applications of P and K fertilizer.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"462 ","pages":"Article 117504"},"PeriodicalIF":6.6,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145269011","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}
GeodermaPub Date : 2025-10-01DOI: 10.1016/j.geoderma.2025.117528
Han Liu , Luyuan Sun , Guopeng Zhou , Li Wan , Guilong Li , Xiaofen Chen , Wenjing Qin , Yongxin Lin , Jia Liu
{"title":"Delayed flooding after green manure incorporation decreases methane emissions and greenhouse gas intensity in rice paddy fields","authors":"Han Liu , Luyuan Sun , Guopeng Zhou , Li Wan , Guilong Li , Xiaofen Chen , Wenjing Qin , Yongxin Lin , Jia Liu","doi":"10.1016/j.geoderma.2025.117528","DOIUrl":"10.1016/j.geoderma.2025.117528","url":null,"abstract":"<div><div>Greenhouse gas (GHG) emissions from paddy fields are strongly influenced by practices such as green manure incorporation and water management. In this study, we examined the effects of incorporating Chinese milk vetch (<em>Astragalus sinicus L.</em>) and applying delayed flooding on methane (CH<sub>4</sub>) and nitrous oxide (N<sub>2</sub>O) emissions, global warming potential (GWP), greenhouse gas intensity (GHGI), soil and surface water properties, and methane-cycling microbial communities. Our approach combined a two-year field experiment in southern China with a complementary microcosm incubation. Green manure incorporation significantly increased CH<sub>4</sub> emissions and boosted rice yield, whereas delayed flooding substantially reduced CH<sub>4</sub> emissions without affecting N<sub>2</sub>O emissions. Among the tested treatments, withholding flooding for 10 days (10DbF) produced the lowest CH<sub>4</sub> emissions and GWP, reducing GHGI by 51.6 % in 2022 and 36.1 % in 2023. CH<sub>4</sub> emissions were positively correlated with soil total nitrogen (STN) and water-dissolved organic carbon (WDOC), indicating their key regulatory roles. Microcosm experiments further showed that 10DbF postponed the CH<sub>4</sub> emission peak and reduced cumulative emissions by 405.1 % compared to immediate flooding (0DbF). Quantitative PCR analysis revealed a significant decline in <em>mcrA</em> gene abundance and in the <em>mcrA</em>/<em>pmoA</em> ratio under 10DbF, while <em>pmoA</em> gene abundance remained largely unaffected. Microbial community profiling indicated clear shifts in methanogenic and methanotrophic assemblages, with delayed flooding decreasing the relative abundances of amplicon sequence variants (ASVs) within key methanogenic taxa (<em>Methanoregula</em> and <em>Methanobacterium</em>) and enriching <em>Methylomonas</em>. These findings demonstrate that combining green manure incorporation with optimized water management can effectively mitigate CH<sub>4</sub> emissions while sustaining rice productivity, offering a promising strategy for climate-resilient and sustainable rice farming.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"462 ","pages":"Article 117528"},"PeriodicalIF":6.6,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145228940","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}
GeodermaPub Date : 2025-10-01DOI: 10.1016/j.geoderma.2025.117523
Zhisheng Yao , Rui Wang , Han Zhang , Lei Ma , Xunhua Zheng , Kai Wang , Wei Zhang , Yong Li , Bo Zhu , Klaus Butterbach-Bahl
{"title":"Temporal-spatial characteristics and environmental controls of annual CH4 fluxes in a Tibetan alpine landscape","authors":"Zhisheng Yao , Rui Wang , Han Zhang , Lei Ma , Xunhua Zheng , Kai Wang , Wei Zhang , Yong Li , Bo Zhu , Klaus Butterbach-Bahl","doi":"10.1016/j.geoderma.2025.117523","DOIUrl":"10.1016/j.geoderma.2025.117523","url":null,"abstract":"<div><div>Alpine ecosystems on the Tibetan Plateau are characterized by different soil hydrothermal conditions and vegetation composition across the elevation gradient, and contribute differently to the net landscape methane (CH<sub>4</sub>) budget. However, the spatiotemporal variation of CH<sub>4</sub> fluxes from alpine ecosystems remains poorly understood, underpinning the uncertainty of upscaling the regional and global CH<sub>4</sub> budgets. Here, we investigated the spatial and temporal patterns and environmental controls of CH<sub>4</sub> fluxes over two years across a Tibetan alpine landscape spanning different elevations (spanning 3200–3500 m above sea level) and major ecosystem types (including alpine meadow, steppe, forest and wetland). On the annual scale, all alpine upland (meadow, steppe and forest) ecosystems consistently functioned as soil CH<sub>4</sub> sinks, ranging between 1.12 and 2.49 kg C ha<sup>−1</sup> yr<sup>−1</sup>, whereas alpine wetlands emitted 17.2–34.3 kg C ha<sup>−1</sup> yr<sup>−1</sup> to the atmosphere. Non-growing season CH<sub>4</sub> fluxes accounted for 29–46 % of the annual budgets, underscoring its significant contribution that was often neglected in previous studies. Our study also demonstrated that for individual alpine upland and wetland ecosystems, soil water content and soil temperature were the main factors regulating the seasonal patterns of CH<sub>4</sub> fluxes. While across all alpine ecosystems, soil water content outweighed temperature as the primary control on the landscape patterns of CH<sub>4</sub> fluxes and higher wetland CH<sub>4</sub> emissions were associated with increased soil inorganic N availability. Despite their small area contribution to the landscape, alpine wetlands emitted disproportionate amounts of CH<sub>4</sub>, weakening the landscape CH<sub>4</sub> sink. The resulting net landscape CH<sub>4</sub> balance was a weak sink of 0.72 kg C ha<sup>−1</sup> yr<sup>−1</sup>. Overall, the multiple parameters and insights gained from our study provide valuable information for better predicting the role of alpine ecosystem CH<sub>4</sub> carbon-climate feedbacks in high-altitude regions.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"462 ","pages":"Article 117523"},"PeriodicalIF":6.6,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145183076","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}
GeodermaPub Date : 2025-10-01DOI: 10.1016/j.geoderma.2025.117529
Floriane Jamoteau , Sarah Wagon , Laurent Thuriès , Samuel Legros , Vladimir Vidal , Adrien Duvivier , Isabelle Basile-Doelsch
{"title":"Amorphous mineral-organic associations in soils: Effective carbon stabilizers undermined by oxalic acid root exudates","authors":"Floriane Jamoteau , Sarah Wagon , Laurent Thuriès , Samuel Legros , Vladimir Vidal , Adrien Duvivier , Isabelle Basile-Doelsch","doi":"10.1016/j.geoderma.2025.117529","DOIUrl":"10.1016/j.geoderma.2025.117529","url":null,"abstract":"<div><div>Mineral-organic associations are key to soil organic matter dynamics, serving as major carbon sinks and nutrient sources for plants and microbes. While most studies focus on associations with crystalline or short-range ordered minerals, recent spectromicroscopy reveals amorphous and heterogeneous associations in some soils, notably nanosized coprecipitates of inorganic oligomers with organics (nanoCLICs). Composed of C, Al, Fe, and Si, these nanostructures may be less stable and more reactive than associations with short-range ordered and crystalline minerals, raising question about their C stabilization potential and the extent of their disruption in the rhizosphere. This study investigates the reactivity of nanoCLICs, emphasizing their C stabilization and disruption potential following root exudate additions (oxalic acid). Laboratory-synthesized and a nanoCLICs-rich Andosol fraction were incubated in microcosms, and C mineralization was tracked over 42 days. Compared to free organic molecules, the nanoCLICs structure reduced C mineralization by 90 %. However, 1–6 % of the C in nanoCLICs was still mineralized, demonstrating a stabilization capacity comparable to that provided by associations with crystalline or short-range ordered minerals. Adding oxalic acid, a model root exudate, increased mineralized C, by a factor of 2 to 8, confirming nanoCLICs’ susceptibility to disruption by root exudates made of oxalic acid. These findings call for greater consideration of very disordered and heterogeneous mineral-organic associations, such as nanoCLICs, in soil C stabilization and nutrient cycling, offering a broader perspective beyond the traditionally emphasized role of crystalline and short-range ordered minerals.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"462 ","pages":"Article 117529"},"PeriodicalIF":6.6,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145268365","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}