Geoderma最新文献

{"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":"https://doi.org/10.1016/j.geoderma.2025.117522","url":null,"abstract":"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, &lt;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 (&lt;250 µm) distributions immediately prior to spectral measurement. Ninety-one air dried soils representing six USDA soil orders were sieved to &lt;2 mm, imaged in five replicates under controlled illumination, and physically fractionated via quantitative laboratory-based sieving into six size classes (&lt;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 &lt;0.10 mm (derived from a measured µm px<ce:sup loc=\"post\">−1</ce: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<ce:sup loc=\"post\">2</ce: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.","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"39 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2025-09-28","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}

{"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":"https://doi.org/10.1016/j.geoderma.2025.117523","url":null,"abstract":"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<ce:inf loc=\"post\">4</ce:inf>) budget. However, the spatiotemporal variation of CH<ce:inf loc=\"post\">4</ce:inf> fluxes from alpine ecosystems remains poorly understood, underpinning the uncertainty of upscaling the regional and global CH<ce:inf loc=\"post\">4</ce:inf> budgets. Here, we investigated the spatial and temporal patterns and environmental controls of CH<ce:inf loc=\"post\">4</ce:inf> 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<ce:inf loc=\"post\">4</ce:inf> sinks, ranging between 1.12 and 2.49 kg C ha<ce:sup loc=\"post\">−1</ce:sup> yr<ce:sup loc=\"post\">−1</ce:sup>, whereas alpine wetlands emitted 17.2–34.3 kg C ha<ce:sup loc=\"post\">−1</ce:sup> yr<ce:sup loc=\"post\">−1</ce:sup> to the atmosphere. Non-growing season CH<ce:inf loc=\"post\">4</ce:inf> 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<ce:inf loc=\"post\">4</ce:inf> fluxes. While across all alpine ecosystems, soil water content outweighed temperature as the primary control on the landscape patterns of CH<ce:inf loc=\"post\">4</ce:inf> fluxes and higher wetland CH<ce:inf loc=\"post\">4</ce:inf> emissions were associated with increased soil inorganic N availability. Despite their small area contribution to the landscape, alpine wetlands emitted disproportionate amounts of CH<ce:inf loc=\"post\">4</ce:inf>, weakening the landscape CH<ce:inf loc=\"post\">4</ce:inf> sink. The resulting net landscape CH<ce:inf loc=\"post\">4</ce:inf> balance was a weak sink of 0.72 kg C ha<ce:sup loc=\"post\">−1</ce:sup> yr<ce:sup loc=\"post\">−1</ce:sup>. Overall, the multiple parameters and insights gained from our study provide valuable information for better predicting the role of alpine ecosystem CH<ce:inf loc=\"post\">4</ce:inf> carbon-climate feedbacks in high-altitude regions.","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"97 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2025-09-28","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}

{"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":"https://doi.org/10.1016/j.geoderma.2025.117524","url":null,"abstract":"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<ce:inf loc=\"post\">2</ce:inf>/Al<ce:inf loc=\"post\">2</ce:inf>O<ce:inf loc=\"post\">3</ce:inf> 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<ce:inf loc=\"post\">1</ce:inf>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.","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"327 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2025-09-27","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}

{"title":"Mapping soil carbon content in two contrasting pedoclimatic regions using a deep learning approach with remote sensing imagery and laboratory spectral datasets","authors":"Hayfa Zayani ,&nbsp;Youssef Fouad ,&nbsp;Didier Michot ,&nbsp;Zeineb Kassouk ,&nbsp;Nicolas Baghdadi ,&nbsp;Maria José Marquez Perez ,&nbsp;Emmanuelle Vaudour ,&nbsp;Zohra Lili-Chabaane ,&nbsp;Christian Walter","doi":"10.1016/j.geoderma.2025.117513","DOIUrl":"10.1016/j.geoderma.2025.117513","url":null,"abstract":"<div><div>Mapping soil properties can help in monitoring spatial and temporal variability in soils. However, the accuracy of predictions based on optical remote sensing data depends on the availability of cloud-free images and the presence of bare soil under suitable surface conditions. The objective of this study was to produce maps of soil organic carbon (SOC) content or soil total carbon (STC) content for two study areas with contrasting pedoclimatic conditions: Naizin (1.5 km²), which has a temperate climate and mainly intensive mixed crop-livestock farms on Luvic Cambisols and Haplic Albeluvisols, and Merguellil (40 km²), which has a semi-arid climate and mainly intensive farms on Fluvisols. We used a deep learning approach that combined remote sensing and laboratory visible, near-infrared and short-wave infrared (Vis-NIR-SWIR) datasets. We developed deep neural network models using all available bare soil pixels from Sentinel-2 (S2) images over one farming year and by measuring soil properties at 58 and 73 soil sampling points in the Naizin and Merguellil study areas, respectively. We used two approaches: (1) using only S2 bands to calibrate models and (2) adding laboratory spectral indices incrementally to the S2 bands in decreasing order of their correlation with SOC or STC content. To compare and analyse the spatial patterns in the SOC and STC maps produced by the two approaches, we applied one model from approach 1 and one model from approach 2. The results showed that this method was able to adapt to the two pedoclimatic contexts. Adding the laboratory indices to the models increased prediction accuracy for both study areas. Although the two approaches yielded similar spatial patterns of SOC or STC content, some differences were observed. Adding the laboratory indices increased intra-field variability in the distribution of SOC content for Naizin but decreased inter- and intra-field variability in the distribution of STC content for Merguellil. The method accurately mapped SOC content in 70 % of the Naizin area and STC content in more than 90 % of the Merguellil area. Future research could assess effects of using different methods for kriging, the potential of using hyper-spectral images for calculating spectral indices which would avoid effects of kriging on the spatial patterns in the maps of soil properties produced and the transferability of the models across different pedoclimatic regions.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"462 ","pages":"Article 117513"},"PeriodicalIF":6.6,"publicationDate":"2025-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145156236","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":"Effects of land-use change on morphological, physicochemical, and mineralogical properties of volcanic soils in southern Chile","authors":"Belén Caurapan ,&nbsp;Franz Zehetner ,&nbsp;Franz Ottner ,&nbsp;Felipe Zúñiga ,&nbsp;Susana Valle","doi":"10.1016/j.geoderma.2025.117510","DOIUrl":"10.1016/j.geoderma.2025.117510","url":null,"abstract":"<div><div>Chilean volcanic soils, such as Andisols and Ultisols, cover much of the country’s arable land and are valued for their unique mineralogical characteristics. This study investigated the effects of land-use change from native forest to silvoagricultural systems on pedogenesis across four volcanic soil types: Acrudoxic Duraquand, Duric Hapludand, Typic Paleudult, and Typic Hapludult. Morphological analyses revealed that soils under agricultural uses have undergone changes in soil structure in addition to a loss in organic horizons. Significant differences were noted in physical and chemical properties, including bulk density, soil organic carbon (SOC), pH, and extractable aluminum. Andisols under croplands displayed higher bulk densities, lower SOC, and decreased extractable aluminum contents compared to those under native forests. Principal component analyses (PCA) revealed a distinct separation between land uses based on andic properties, suggesting, in some cases, a partial loss of these distinctive characteristics. Mineralogical analyses detected allophane, gibbsite, kaolinite, and hydroxy-interlayered minerals; however, no direct evidence was found for crystalline clay mineralogical transformations due to land-use change. Furthermore, while future studies would benefit from a finer-scale soil classification to account for the geomorphological variability of southern Chile, the present findings already highlight clear impacts of land-use change on pedogenesis in volcanic soils. Keywords: Volcanic soils, Land-use change, Pedogenesis, Andic properties, Soil mineralogy.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"462 ","pages":"Article 117510"},"PeriodicalIF":6.6,"publicationDate":"2025-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145156177","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":"Numerical modeling of ammonium and nitrate nitrogen transport in estuarine wetland sediments: a case study of the Minjiang Estuary","authors":"Lanqing Qiu, Jun Xia, Xingwei Chen, Chuan Tong, Zipeng Gu","doi":"10.1016/j.geoderma.2025.117514","DOIUrl":"https://doi.org/10.1016/j.geoderma.2025.117514","url":null,"abstract":"The transport and transformation of ammonium nitrogen (NH<ce:inf loc=\"post\">4</ce:inf><ce:sup loc=\"post\">+</ce:sup>-N) and nitrate nitrogen (NO<ce:inf loc=\"post\">3</ce:inf><ce:sup loc=\"post\">–</ce:sup>-N) in estuarine wetland sediments are influenced by tidal fluctuations. However, current research on this topic primarily relies on field experiments, which are time-consuming and often lack continuity, particularly regarding the dynamic changes in nitrogen (N) transformation during tidal cycles. In this study, the Minjiang Estuary wetland in China was selected as the research area to investigate the transport and transformation of NH<ce:inf loc=\"post\">4</ce:inf><ce:sup loc=\"post\">+</ce:sup>-N and NO<ce:inf loc=\"post\">3</ce:inf><ce:sup loc=\"post\">−</ce:sup>-N in sediments under tidal influence. A numerical model based on HYDRUS was developed, and its simulation accuracy was within acceptable limits. Transformation parameters for N at different tidal flats and months were successfully obtained. Results suggested that nitrification, mineralization, and denitrification coefficients tended to be higher in summer (August) than in autumn (November), although the seasonal pattern varied across tidal flat positions and soil depths. Spatially, nitrification and mineralization often decreased with depth, whereas denitrification tended to increase. With greater inundation depth, denitrification and mineralization often showed an increasing trend. Model simulations indicated that sediment inundation depth and solute concentration were key factors controlling NO<ce:inf loc=\"post\">3</ce:inf><ce:sup loc=\"post\">−</ce:sup>-N leaching, which increased with tidal level but with a certain degree of lag, especially during spring tides, while neap tides showed greater variability at intermediate tidal flat. This study provides theoretical insights into N transport parameters in estuarine wetland sediments and offers a modeling approach exemplified by the Minjiang Estuary, contributing to the sustainable management of estuarine wetland ecosystems.","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"4 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2025-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145183078","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 contributions of anaerobic decomposition to greenhouse gas emissions of agriculturally used peatlands","authors":"Jim Boonman ,&nbsp;Duygu Tolunay ,&nbsp;Joost Keuskamp ,&nbsp;Liam Heffernan ,&nbsp;Alexander J.V. Buzacott ,&nbsp;Sarah Faye Harpenslager ,&nbsp;Gijs van Dijk ,&nbsp;Mariet Hefting ,&nbsp;Ype van der Velde","doi":"10.1016/j.geoderma.2025.117521","DOIUrl":"10.1016/j.geoderma.2025.117521","url":null,"abstract":"<div><div>Globally, peatlands store one third of global soil carbon. Peatlands accumulate carbon under waterlogged anoxic conditions, but current drainage increases oxygen availability enhancing degradation of these carbon reserves. Therefore, drainage is responsible for ∼ 2 % of anthropogenic greenhouse gas (GHG) emissions. GHG emission estimates from drained peatlands are often based on hydrological proxies, but these methods are known to result in consistent inaccuracies. In this research, we propose to improve these estimates by using the redox potential that controls peat degradation more directly as compared to hydrological proxies. We aimed to quantify in-situ (net) soil production rates of CO₂ and CH₄ by combining in-situ redox potential measurements with corresponding laboratory basal respiration rates scaled to in-situ soil temperature. Using this approach, we estimated soil CO₂ and net CH₄ production rates at 12 field sites over multiple years and validated these estimates by comparing them to aboveground Net Ecosystem Carbon Balance (NECB) measurements using continuously operating chambers (for CO₂) and eddy covariance measurements (for CH₄) over the same sites and timeframes. We hypothesized that (1) laboratory incubation measurements can serve as a basis to estimate field-scale CO₂ and CH₄ emissions, (2) compared to water table depth, the redox potential is a more reliable parameter for estimating soil CO₂ production, and (3) anaerobic respiration processes contribute substantially to peat decomposition and soil CO₂ production. Averaged soil production estimates over multipole years for all sites of CO₂ showed strong agreement with measured NECBs (concordance correlation coefficient, CCC = 0.80) and net soil production estimates of CH₄ showed moderately strong agreement (CCC = 0.65) with CH₄ emissions. Using water table depth instead of soil redox condition to calculate soil CO₂ production rates resulted in a very low agreement with measured NECBs (CCC = 0.08) due to overestimation of the prevalence of oxic conditions. Shorter term comparisons generally resulted in lower CCC values, likely due to (bio)chemical legacy effects that balanced out over longer timescales. Anaerobic respiration processes accounted for 68 % of total soil CO₂ production over all sites, with 61 % originating from soil layers that were exposed to oxygen within the past 1.5 years, also likely influenced by biological and chemical legacy effects. By bridging the gap between laboratory and field-scale, our approach provides a valuable tool for assessing GHG emissions from drained peatlands and enhances our understanding of aerobic and anaerobic peat decomposition processes.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"462 ","pages":"Article 117521"},"PeriodicalIF":6.6,"publicationDate":"2025-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145156191","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":"Spatio-temporal stability of micro-dams as mitigation measures and disconnective elements to water erosion in potato farming","authors":"Matthias Konzett,&nbsp;Thomas Brunner,&nbsp;Peter Strauss,&nbsp;Elmar M. Schmaltz","doi":"10.1016/j.geoderma.2025.117519","DOIUrl":"10.1016/j.geoderma.2025.117519","url":null,"abstract":"<div><div>Micro-dams in potato fields help reduce surface runoff and soil loss. This study evaluated their stability by examining the effects of topography, rainfall intensity, and cover crops on failure mechanisms. Micro-dams were categorized as either without cover crops (MD) or with cover crops (MD + CC), which acted as potential stabilizing factors. Field observations and UAV imagery were taken from five potato fields in Northeast Austria to create a spatio-temporal inventory of failed micro-dams. The UAV imagery enabled the construction of Digital Elevation Models (DEM) for all observations, with failure detected through an automatic routine and compared to in-field mapping. Various topographic factors, such as slope steepness and the Topographic Wetness Index (TWI), were used to classify micro-dams into stable, damaged, or broken states. Rainfall intensities were calculated to compare triggering events, and a Generalized Additive Model (GAM) assessed the resilience of micro-dams across Austria’s main potato production areas. Results indicated that MD + CC were 20 % less likely to break (OR = 0.31, 95 % CI: 0.24 – 0.41, p &lt; 0.001), showcasing a higher proportion of stable micro-dams. These differences were significant among all state classes. MD + CC exhibited both damaged and stable micro-dams in topographic areas where standard MD had failed. The GAM results also pointed to a more sustainable performance for MD + CC. While an exact rainfall intensity threshold for failure was not established, specific conditions (53 mm total rainfall and 27.7 mm h⁻¹ intensity) were identified as indicative until future research is undertaken.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"462 ","pages":"Article 117519"},"PeriodicalIF":6.6,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145156190","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":"Divergent responses of particulate and mineral-associated organic carbon stock to grazing in a Eurasian temperate meadow steppe","authors":"Haonan Guo ,&nbsp;Xiaoping Xin ,&nbsp;Jiquan Chen ,&nbsp;Zhigang Zhao ,&nbsp;Hui Li ,&nbsp;Cuixia Jiang ,&nbsp;Zihao Li ,&nbsp;Feng Liu ,&nbsp;Yufan Si ,&nbsp;Ruirui Yan ,&nbsp;Jianming Deng","doi":"10.1016/j.geoderma.2025.117516","DOIUrl":"10.1016/j.geoderma.2025.117516","url":null,"abstract":"<div><div>Grazing plays a pivotal role in shaping the carbon dynamics within grassland ecosystems. Although the impact of grazing on soil carbon dynamics has recently become a major focus, the mechanistic drivers of grazing effects on functionally distinct carbon fractions remain unclear. Here, we employed a combined density and particle-size fractionation approach to divide the soil carbon pool into three distinct functional fractions (fPOC: free particulate organic carbon, oPOC: occluded particulate organic carbon, and MAOC: mineral-associated organic carbon), and investigated their responses to four different grazing intensities (Non-grazing: G0.00 (0 AU ha⁻¹), light grazing: G0.23 (0.23 AU ha⁻¹), moderate grazing: G0.46 (0.46 AU ha⁻¹) and heavy grazing: G0.92 (0.92 AU ha⁻¹), where 1 AU = 500 kg of adult cattle) and further explored the potential mechanisms involved in the Inner Mongolia meadow grassland. Our results show that POC stock has greater sensitivity to grazing disturbance than MAOC stock. Light to moderate grazing promoted the increase in both fPOC and oPOC stocks (fPOCs, oPOCs) compared to non-grazing, while heavy grazing (G0.92) significantly decreased relative to moderate grazing. In contrast, all intensity levels decreased in mineral-associated organic carbon stock (MAOCs). The structural equation model (SEM) indicates that grazing increases POCs by increasing belowground biomass input and suppressing microbial processes (microbial and enzyme activities). In addition, grazing-induced soil environment deterioration and nutrient depletion inhibit the input of microbial biomass and necromass, ultimately reducing MAOC formation. Furthermore, the distribution of POC increased significantly with grazing intensity, indicating enhanced SOC activity. Overall, our results highlight that grazing-induced shifts in plant above-belowground biomass allocation strategy and microbial enzymatic activity collectively drive soil carbon dynamics.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"462 ","pages":"Article 117516"},"PeriodicalIF":6.6,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145109201","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":"Seasonal soil respiration responses to fencing vary by alpine grassland type in the Tibetan Plateau","authors":"Luyun Chen ,&nbsp;Jeremy R. Shaw ,&nbsp;Xiaoyang Zeng ,&nbsp;Chenjun Du ,&nbsp;Yongheng Gao","doi":"10.1016/j.geoderma.2025.117517","DOIUrl":"10.1016/j.geoderma.2025.117517","url":null,"abstract":"<div><div>Fencing is widely applied for grassland restoration on the Qinghai-Tibet Plateau. However, considerable uncertainty remains in how soil respiration (Rs) and its components, autotrophic (Ra) and heterotrophic (Rh) respiration, respond to fencing in different alpine grassland types. This research investigated the impact of fencing on Rs, Rh, and Ra during growing and non-growing seasons in alpine steppe and alpine meadow, and elucidated the underlying biotic and abiotic mechanisms by assessing plant biomass and community data (e.g., species richness, abundance), soil properties and microbial community composition and diversity. Results revealed divergent responses of Rs, Rh, and Ra to fencing between alpine meadow and steppe ecosystems. In the more mesic alpine meadow, fencing significantly enhanced Rh by 19.3% during the growing season, while Rs and Ra remained largely unchanged. The increased growing season Rh rate in alpine meadow was primarily driven by nitrate nitrogen concentrations. In contrast, fencing exerted more pronounced effects in the relatively xeric alpine steppe, where growing season Rs, Rh, and Ra increased by 93.3%, 66.8%, and 234.3%, respectively. During the non-growing season, Rs and Rh also rose by 50.2% and 55.0%. In the steppe, the elevation of Rh across both seasons was strongly related to substrate availability and microbial community composition, whereas the increase in Ra during the growing season was mainly attributed to enhanced plant biomass. Our study highlights the importance of considering grassland type and seasonal dynamics when assessing fencing effects on soil carbon processes, providing insights into mechanisms regulating soil respiration in alpine ecosystems.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"462 ","pages":"Article 117517"},"PeriodicalIF":6.6,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145109739","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}