Geoderma最新文献

{"title":"Effects and mechanisms of warming on the relationship between soil organic matter degradation and methylmercury production in Hg-contaminated soil","authors":"Siqi Zhang ,&nbsp;Sihua Zhu ,&nbsp;Shanyi Tian ,&nbsp;Jianxu Wang ,&nbsp;Yongguang Yin ,&nbsp;Jitao Lv ,&nbsp;Yongmin Wang ,&nbsp;Tao Jiang ,&nbsp;Zhenwu Tang ,&nbsp;Dingyong Wang","doi":"10.1016/j.geoderma.2025.117326","DOIUrl":"10.1016/j.geoderma.2025.117326","url":null,"abstract":"<div><div>The degradation of soil organic matter (SOM) is an essential process that not only drives the production of greenhouse gases (GHGs) but also influences the environmental fate of pollutants, such as mercury (Hg), specifically methylmercury (MeHg) production. However, the relationship between these processes and their response to warming remains unclear. To address this gap, we conducted a 60-day microcosm incubation period using mimic-contaminated soils with varying Hg levels to investigate the effects of warming on SOM degradation and MeHg production. These results indicate that Hg stress does not significantly affect GHG production but increases the temperature sensitivity (Q₁₀) of SOM degradation. This implies that warming increases the feedback of carbon release in contaminated soil, particularly when considering seasonal temperature dynamics or prospective global warming scenarios. Additionally, warming can significantly promote GHG production. However, warming did not significantly affect MeHg production, except in the high Hg treatment (i.e., HgH), due to minimal changes in the Hg fractions that regulate MeHg production. Furthermore, regardless of temperature changes, the relationship between GHGs and MeHg shifted from positive to negative as Hg levels increased. This highlights the need to balance carbon emission reduction and pollutant treatment policies to effectively reduce risks in contaminated sites. In conclusion, in terms of the current development of C management strategies for mitigating climate change and enhancing carbon sequestration, the turnover of SOM and its ecological implications for contaminated soils should be revisited. Future research should incorporate contaminated soils into global carbon models to improve SOM turnover predictions in terrestrial systems.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"458 ","pages":"Article 117326"},"PeriodicalIF":5.6,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144084588","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":"Combining temperature ramp dry combustion and mid-infrared spectroscopy for enhanced soil organic carbon characterisation","authors":"Lewis Walden,&nbsp;Raphael A. Viscarra Rossel","doi":"10.1016/j.geoderma.2025.117316","DOIUrl":"10.1016/j.geoderma.2025.117316","url":null,"abstract":"<div><div>Soil organic carbon (SOC) is comprised of a complex mixture of plant and microbial-derived compounds with varying chemical compositions and stability. Understanding these components is crucial for modelling SOC turnover and stability. Conventional fractionation methods moslty use physical or chemical separations, but techniques such as mid-infrared (MIR) spectroscopy and thermal ramp dry combustion (TRDC) offer complementary, rapid approaches for SOC characterisation. This study integrates MIR spectroscopy and TRDC to characterise plant-derived compounds in soils. Using soils dosed with six plant-derived compounds (cellulose, lignin, starch, pectin, xylose, and biochar), we investigated their thermograms and MIR spectra. Each compound exhibited unique thermal decomposition peaks and MIR absorptions, reflecting their distinct chemical structures and oxidative stability. Correlation analyses revealed strong relationships between thermal peaks and MIR features. Models that combined MIR and TDRC spectra could estimate cellulose (<span><math><mrow><msub><mrow><mi>ρ</mi></mrow><mrow><mi>c</mi></mrow></msub><mo>=</mo><mn>0</mn><mo>.</mo><mn>92</mn></mrow></math></span>), biochar (<span><math><mrow><msub><mrow><mi>ρ</mi></mrow><mrow><mi>c</mi></mrow></msub><mo>=</mo><mn>0</mn><mo>.</mo><mn>95</mn></mrow></math></span>), pectin (<span><math><mrow><msub><mrow><mi>ρ</mi></mrow><mrow><mi>c</mi></mrow></msub><mo>=</mo><mn>0</mn><mo>.</mo><mn>77</mn></mrow></math></span>) and starch (<span><math><mrow><msub><mrow><mi>ρ</mi></mrow><mrow><mi>c</mi></mrow></msub><mo>=</mo><mn>0</mn><mo>.</mo><mn>87</mn></mrow></math></span>). Our findings show the potential for combining MIR spectroscopy and TRDC to characterise SOC chemical composition. By identifying distinct thermal and spectral features of plant-derived compounds, the combined approach could identify contributions of plant-derived compounds to labile and stable carbon pools, for enhancing our understanding of SOC decomposability. These methods may provide new insights into SOC turnover and stability mechanisms when applied to fractionated soils.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"458 ","pages":"Article 117316"},"PeriodicalIF":5.6,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144084587","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 variations in soil erosion resistance under tap and fibrous root systems grasslands on the Chinese Loess Plateau","authors":"JianFang Wang ,&nbsp;YanFen Yang ,&nbsp;Bing Wang ,&nbsp;GuoBin Liu","doi":"10.1016/j.geoderma.2025.117350","DOIUrl":"10.1016/j.geoderma.2025.117350","url":null,"abstract":"<div><div>Vegetation growth can induce the seasonal variation in soil erosion resistance during a growing season, reflected by rill erodibility (<em>Kr</em>) and critical shear stress (<em>τ_c</em>).</div><div>However, few studies have been conducted to quantify the seasonal variations in erosion resistance under different root type grasslands. This study was conducted on the seasonal variations in soil erosion resistance under tap and fibrous root systems grasslands on the Chinese Loess Plateau, and quantified the potential influencing factors of soil erosion resistance. The undisturbed soil samples were collected over 30-day intervals from April to September 2021. Soil detachment capacity by concentrated flow was measured in a hydraulic flume with the fixed bed under six shear stresses to determine soil erosion resistance. The results showed that the <em>Kr</em> decreased over the growing season as a power function, and the <em>Kr</em> of annual herbaceous plants decreased faster than that of perennial herbaceous plants. Compared with the bare control soil, the <em>Kr</em> of grasslands decreased by 4.07–95.78 %, <em>τ_c</em> increased by 141.26–176.35 %. Generally, the <em>Kr</em> of annual herbaceous plants was 11.58 times higher, and <em>τ_c</em> was 15.48 % lower than perennial herbaceous plants. Differences in <em>Kr</em> were also observed between plants with tap and fibrous root systems. Plants with tap root systems had a higher <em>Kr</em>, which was 2.83 times that of plants with fibrous root systems. Plant root systems and soil were all affected in terms of <em>Kr</em> and <em>τ_c</em>, root system and soil contributions were 41.0 and 3.4 % for <em>Kr</em>, and 9.1 % and 18.8 % for <em>τ_c</em>, respectively. In addition, <em>Kr</em> decreased exponentially with increasing root mass, length, and surface area density, and also decreased with increasing bulk density, cohesion, and water-stable aggregate content. The <em>τ_c</em> increased with increasing bulk density as a power function. Finally, <em>Kr</em> was effectively predicted from using water-stable aggregates content and root surface area density. The performance of the developed model is satisfactory (<em>NSE</em> = 0.85).</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"458 ","pages":"Article 117350"},"PeriodicalIF":5.6,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144084589","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":"Long-term management effects on depth gradients of 13C, 15N and C/N ratio in agricultural soils","authors":"Laura E. Skadell ,&nbsp;Florian Schneider ,&nbsp;Sara L. Bauke ,&nbsp;Wulf Amelung ,&nbsp;Axel Don","doi":"10.1016/j.geoderma.2025.117341","DOIUrl":"10.1016/j.geoderma.2025.117341","url":null,"abstract":"<div><div>Agricultural management practices influence the turnover and residence time of soil organic matter (SOM) and thus can contribute to carbon (C) removal from the atmosphere. However, advanced analytical techniques are needed to disentangle the interlinked processes of SOM stabilisation and destabilisation, as well as its built-up and decomposition. Stable isotopes of C (δ¹³C) and nitrogen (N; δ¹⁵N) as well as the carbon-to-nitrogen (C/N) ratio provide information about the quality and thus origin and turnover SOM. The aim of this study was to quantify the effect of different agricultural management practices (mineral fertilisation, farmyard manure (FYM) application, straw incorporation, crop rotations, liming, irrigation and reduced tillage) on these indicators in topsoil and subsoil. Ten German long-term experiments (LTEs) were sampled down to 100 cm depth. Changes in SOC and N content were assessed as indicators of SOM quantity and changes in δ¹³C, δ¹⁵N and C/N ratios were assessed as indicators of SOM quality. Increases in C and N content were mainly affected in topsoil by mineral fertilisation, FYM, straw and irrigation. Changes in δ¹³C were limited to crop rotations (+0.62 ‰) and FYM (−0.27 ‰) in topsoil, but liming effects also reached down to 70 cm (−0.46 ‰ on average). Mineral fertilisation reduced the δ¹⁵N values in topsoil (−0.12 ‰), while the application of FYM increased them (+0.53 ‰), indicating different N sources. The δ¹⁵N values in the subsoil changed due to crop rotations (+0.62 ‰) and reduced tillage (−0.96 ‰). Specific management practices did not change C/N ratios significantly, with the exception of NPK fertilisation in topsoil (−1.32). Variations in SOC and total N content were more than 50 % greater in subsoil than in topsoil, but ¹³C and ¹⁵N did not follow this trend, indicating a decoupling of changes in C and N content and changes in SOM quality. This study revealed challenges in the detection of subsoil effects due to the low SOM content that in some LTEs unexplained large spatial variability in δ¹⁵N in subsoil. Since agricultural management practices change ¹³C, ¹⁵N and C/N ratios at least in topsoil, these variations need to be considered in isotope studies.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"458 ","pages":"Article 117341"},"PeriodicalIF":5.6,"publicationDate":"2025-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144070713","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":"Permafrost thawing by soil transplantation alters the functional genetic potential of the alpine permafrost microbiome","authors":"Maomao Feng ,&nbsp;Gilda Varliero ,&nbsp;Carla Perez-Mon ,&nbsp;Serina Robinson ,&nbsp;Weihong Qi ,&nbsp;Beat Stierli ,&nbsp;Beat Frey","doi":"10.1016/j.geoderma.2025.117339","DOIUrl":"10.1016/j.geoderma.2025.117339","url":null,"abstract":"<div><div>Global warming has led to permafrost thawing in mid-latitude alpine regions, resulting in greater availability of carbon (C) and nutrients in soils. However, how these changes will impact the functional genetic potential of permafrost soil microbiomes, and subsequently, how they will influence the microbially mediated feedback of mountain soils under climate change remains unknown. To help answer this question, we conducted a permafrost thawing experiment on the north-facing slope near the summit of Muot da Barba Peider (2979 m above sea level) in the Swiss Alps. Specifically, we transplanted permafrost soils from a depth of 160 cm to the active-layer topsoils (0–18 cm) and incubated the soils <em>in situ</em> for three years. Using shotgun metagenomics, we found that transplantation significantly altered the gene structure of the permafrost microbiome, with changes occurring in the short term (&lt; one year) and remaining stable over time. Transplanted soils exhibited an enhanced functional genetic potential, particularly for genes related to “Information storage and processing”, “Cellular processes and signaling” and “Metabolism” functions, which suggests increased cellular processes and metabolism. Carbohydrate-active enzymes involved in the degradation of both labile (such as starch) and recalcitrant (such as lignin) C substrates were enriched in transplanted soils, indicating an enhanced C-degradation potential. Nitrogen (N)-cycling genes related to the degradation and synthesis of N compounds, denitrification, assimilation and dissimilatory nitrate reduction were overrepresented in the transplanted soil, pointing to enhanced N assimilation and transformation potential. Our study elucidates how the permafrost microbiome may functionally respond to warming in the European Alps. This research complements observations from Tibetan and Arctic regions, improving our understanding of functional changes in thawing permafrost globally.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"458 ","pages":"Article 117339"},"PeriodicalIF":5.6,"publicationDate":"2025-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144070712","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":"Controls on soil organic carbon across soil depths in tropical and temperate non-volcanic regions","authors":"Han Lyu ,&nbsp;Kenta Ashida ,&nbsp;Satomi Urayama ,&nbsp;Arief Hartono ,&nbsp;Method Kilasara ,&nbsp;Antoine David Mvondo Ze ,&nbsp;Atsushi Nakao ,&nbsp;Soh Sugihara ,&nbsp;Randy A. Dahlgren ,&nbsp;Shinya Funakawa ,&nbsp;Tetsuhiro Watanabe","doi":"10.1016/j.geoderma.2025.117335","DOIUrl":"10.1016/j.geoderma.2025.117335","url":null,"abstract":"<div><div>Soil organic carbon (SOC) is fundamental for climate regulation, soil fertility, biodiversity, and healthy terrestrial ecosystems. Understanding the key controllers and their pathways is required to estimate SOC distribution and predict C sequestration potential. Previous research emphasized the significant impact of active Al/Fe (acid-oxalate extractable) on SOC content, especially in volcanic soils, yet gaps persist in understanding the interactions among SOC, active Al/Fe, climate, and non-volcanic parent materials across different soil depths. Herein, we explore these dynamics using random forest regression (RFR) and structural equation modeling (SEM). Our analysis included 17 SOC-related physicochemical soil variables and 4 climatic properties across topsoil and subsoil horizons at 211 sites (2 depths). The study covers 178 tropical and 33 temperate sites from sub-humid to humid non-volcanic regions, predominantly with acidic to neutral soil pH. We found that SOC variance explained by SEMs (54 % for topsoil, 75 % for subsoil) closely matched RFR outcomes (61 % for topsoil, 72 % for subsoil), highlighting the efficacy of our SEMs in identifying key SOC controllers: mean annual temperature (MAT) and excess precipitation (moisture index: precipitation – potential evapotranspiration) for climate, Al₂O₃ + Fe₂O₃ (total Al and Fe contents expressed as oxides) for parent material, and active Al/Fe and pH for soil properties. Partial dependence in RFRs and path coefficients in SEM indicated MAT, active Al/Fe, and pH directly contribute to topsoil SOC, whereas active Al/Fe directly controls SOC in subsoil. Furthermore, SEMs indicated bidirectional interaction between SOC and active Al/Fe in topsoil, where active Al/Fe increased SOC and vice versa, while in subsoil, active Al/Fe has substantial unidirectional control over SOC. Importantly, both climate and parent material indirectly affected SOC by regulating active Al/Fe contents, particularly in subsoil. These findings enable predicting SOC distribution and refining SOC dynamics models by focusing on the direct and indirect impacts of active Al/Fe, climate and parent material across different soil depths and climatic zones in non-volcanic regions.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"458 ","pages":"Article 117335"},"PeriodicalIF":5.6,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144068471","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":"Lithology and bioclimate impacts on soil organic phosphorus speciation and the relationship between phosphatase and organic phosphorus in California temperate forest","authors":"Suwei Xu ,&nbsp;Chunhao Gu ,&nbsp;Stewart G. Wilson ,&nbsp;Rota Wagai ,&nbsp;Yuhei Nakayama ,&nbsp;Andrew J. Margenot","doi":"10.1016/j.geoderma.2025.117314","DOIUrl":"10.1016/j.geoderma.2025.117314","url":null,"abstract":"<div><div>The dynamic equilibrium between soil phosphatase activities and soil organic phosphorus (P_o) species can be impacted by soil forming factors. While much research has addressed soil P_o dynamics as a function of time using chronosequences, understanding of lithology and bioclimate impacts on soil P cycling remains comparatively limited. We tested hypothesized interactive impacts of lithology and bioclimate on the quantity and quality of soil P_o, and relationships between P_o composition and phosphatase activities using a full factorial combination of three lithologies (andesite, basalt, granite) and four bioclimatic zones (blue oak, ponderosa pine, white fir, red fir) constrained by elevation ranges across the Sierra Nevada and southern Cascades in California, USA. Activities of acid and alkaline phosphomonoesterase (PME) and phosphodiesterase (PDE) were positively associated with concentrations of P_o species determined by NaOH-EDTA extraction and solution ³¹P nuclear magnetic resonance (NMR) spectroscopy. Concentrations of P_i and P_o species and species class (i.e., phosphomonoesters, phosphodiesters) were positively related to PME activities, whereas PDE activity was correlated to P species concentrations at species class level of phosphodiesters. Soil inositol hexakisphosphate (IHP) and most non-IHP monoesters (e.g., glucose-6′ phosphate, α- and β-glycerophosphate, phosphocholine), phosphodiesters (i.e., deoxyribonucleic acid), and inorganic phosphates (i.e., (pyro)phosphate) were 68–232 % higher in soils developed on andesite (monoester 312 mg kg⁻¹; diester 25 mg kg⁻¹), followed by basalt (monoester 174 mg kg⁻¹; diester 20 mg kg⁻¹), and lowest in granite (monoester 133 mg kg⁻¹; diester 12 mg kg⁻¹), reflecting greater contents of poorly crystalline Fe/Al oxides and P from intermediate parent materials. Bioclimatic impacts on concentrations and proportions of P_o species were highly specific to lithology, with P species concentrations lowest at the highest elevation (red fir) for andesite- (monoester 265 mg kg⁻¹) and basalt-derived soils (monoester 67 mg kg⁻¹), whereas P concentrations in granite-derived soil (monoester 108–183 mg kg⁻¹) were largely uninfluenced by bioclimate. Relationships among phosphatase activities and P_o species concentrations were mainly observed in mafic material-derived soils, and were highly specific to P species at a given bioclimate. Integrating lithology and bioclimate context may enable more comprehensive assessments of soil P cycling.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"458 ","pages":"Article 117314"},"PeriodicalIF":5.6,"publicationDate":"2025-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143943481","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":"Deep learning segmentation of soil constituents in 3D X-ray CT images","authors":"Maxime Phalempin ,&nbsp;Lars Krämer ,&nbsp;Maik Geers-Lucas ,&nbsp;Fabian Isensee ,&nbsp;Steffen Schlüter","doi":"10.1016/j.geoderma.2025.117321","DOIUrl":"10.1016/j.geoderma.2025.117321","url":null,"abstract":"<div><div>Accurate segmentation of soil constituents in X-ray CT imagery is critical for advancing our understanding of soil structure dynamics. However, difficulties arise because of the overlapping X-ray attenuation of soil constituents, which makes segmentation based on voxel intensity alone impossible. In this study, we explore the potential of nnUNet, a deep learning-based semantic segmentation model, for applications in soil science. We evaluated nnUNet on three challenging datasets: (1) complex soil structure with numerous material classes with overlapping gray value ranges, (2) fine roots in noisy images, and (3) permafrost with gradual gray value transitions between sediment types. The performance of nnUNet was compared to other reference methods, namely Ilastik, Rootine v.2, and manual thresholding. The Dice scores indicated overall good model performance across all three datasets. Compared to the reference methods, nnUNet outperformed Ilastik on Dataset 1. For Dataset 2, nnUNet produced segmentations with fewer false-positive roots than Rootine v2; however, this came at the expense of missing fine roots that were barely visible to the naked eye and, therefore, not annotated. In Dataset 3, we encountered challenges in annotating classes due to gradual transitions in voxel intensity. Our study underscores that deep learning models like nnUNet perform well for the segmentation of complex soil structures and could assist the development of a generalized segmentation model, thereby fostering standardization in soil structure analysis. To achieve this, increased access to diverse and well-curated annotations is still necessary.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"458 ","pages":"Article 117321"},"PeriodicalIF":5.6,"publicationDate":"2025-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143934826","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":"Magnitudes, patterns, controls and mitigation potentials of net ecosystem carbon balances across wetlands in China","authors":"Lei Ma ,&nbsp;Dezhao Gan ,&nbsp;Zheng Li ,&nbsp;Dongyou Wu ,&nbsp;Wei Pu ,&nbsp;Xiangyue Chen ,&nbsp;Gaofeng Zhu ,&nbsp;Shuli Niu ,&nbsp;Jinsong Wang ,&nbsp;Ruijun Long ,&nbsp;Hongchao Zuo","doi":"10.1016/j.geoderma.2025.117332","DOIUrl":"10.1016/j.geoderma.2025.117332","url":null,"abstract":"<div><div>China contains Asia’s largest wetlands, which include diverse wetland types, e.g., peatlands, marshes and mangroves; these wetlands are found from inland to coastal regions. Over the past four decades, considerable amounts of natural wetlands have been drained, thus severely decreasing their carbon (C) sequestration ability. Recent rewetting has been initiated to restore wetland ecosystem services and mitigate carbon dioxide (CO₂) emissions. However, the magnitudes, patterns, controls and mitigation potentials of annual net ecosystem C balances (NECB) have not been adequately studied, leading to large uncertainties in predicting wetland C cycles under climate change and anthropogenic activities across different wetlands in China. These influencing factors include the combinations of vertical net ecosystem exchange of CO₂ (NEE) and horizontal C removal through biomass harvest, as well as dissolved organic and inorganic C (DOC and DIC) exports. Here, using the annual measurement of NECB from 148 sites across different wetlands in China, we found that the annual NECB varied widely from –9413 to + 8760 kg C ha⁻¹ yr⁻¹; these fluxes were collectively influenced by wetland status, wetland location, and wetland type. Drainage turned natural wetlands from net C sinks to net C sources (<em>p</em> &lt; 0.05), regardless of whether wetlands were inland or coastal, while rewetting significantly (<em>p</em> &lt; 0.05) reversed the net C loss trends from drained wetlands to net C uptake in rewetted wetlands. Coastal wetlands had significantly greater (<em>p</em> &lt; 0.05) annual C uptake than inland wetlands, with coastal mangroves exhibiting the highest uptake rates. Eighty percent of the spatial variations in the annual NECB were explained (<em>p</em> &lt; 0.0001) by the spatial variations in the mean annual temperature (MAT) and water table depth (WTD) across different wetlands in China. Scenario analysis showed that drained wetlands should be rewetted promptly; postponing rewetting causes larger emissions from continued C losses from drained wetlands.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"458 ","pages":"Article 117332"},"PeriodicalIF":5.6,"publicationDate":"2025-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143934824","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":"Reconciling historic and contemporary sampling of soil organic carbon stocks: Does sampling approach create systematic bias?","authors":"Sam McNally ,&nbsp;Jack Pronger ,&nbsp;Jordan Goodrich ,&nbsp;Kara Allen ,&nbsp;Scott Graham ,&nbsp;Stephen McNeill ,&nbsp;Pierre Roudier ,&nbsp;Tim Norris ,&nbsp;Alice Barnett ,&nbsp;Louis Schipper ,&nbsp;Paul Mudge","doi":"10.1016/j.geoderma.2025.117338","DOIUrl":"10.1016/j.geoderma.2025.117338","url":null,"abstract":"<div><div>Accurate determination of soil organic carbon stocks is important to track long-term change due to land management or land use, for greenhouse gas (GHG) inventory reporting, and carbon trading associated with these changes. Typically, these stock measurements are carried out, using either horizon-based or continuous core sampling, to collect soil bulk density, organic carbon content and depth of the desired layer. Differences in methods also relate to the soil organic carbon (SOC) collection via a core or a horizon scraping. There is also growing consensus that stocks should be calculated on an equivalent soil mass basis to reduce error in measurements and account for biases related to changes in bulk density. Here we quantify SOC stocks measured using four different field sampling methods (variations of depth-based and horizon-based sampling using pits, or continuous core sampling). We then compare the results using either: i) a fixed-depth; or ii) an equivalent soil mass calculation (ESM) approach. Our results demonstrate that there was no bias associated with depth-based or horizon-based methods, where bulk density was determined in the centre of each layer, and carbon content across the full horizon, compared to a core sampling method where both bulk density and SOC content were determined continuously for the whole profile in fixed-depth increments. While there are small differences between methods when fixed depth sampling was used, these differences can be substantially reduced when using ESM. Reprocessing of SOC stock data using ESM should be carried out to reconcile any potential differences caused between sampling methods in historic and contemporary datasets.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"458 ","pages":"Article 117338"},"PeriodicalIF":5.6,"publicationDate":"2025-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143934825","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}