Geoderma最新文献

{"title":"The predominance of root- and salt-marsh-derived soil organic carbon in a mangrove poleward range expansion front","authors":"Prakhin Assavapanuvat ,&nbsp;Joshua L. Breithaupt ,&nbsp;Ding He ,&nbsp;Ralph N. Mead ,&nbsp;Thomas S. Bianchi","doi":"10.1016/j.geoderma.2025.117249","DOIUrl":"10.1016/j.geoderma.2025.117249","url":null,"abstract":"<div><div>Due to global warming, temperate salt marshes (e.g., <em>Spartina alterniflora</em> and <em>Juncus roemerianus</em>) are being overtaken by poleward migrating mangroves (e.g., <em>Avicennia germinans</em> and <em>Rhizophora mangle</em>). While bulk soil organic carbon (SOC) stocks have been widely compared across mangrove and salt marsh habitats, differentiation of SOC derived from leaves and roots of each mangrove and salt marsh species remains a challenge. Hence, we used multiple biomarkers and proxies (stable isotopes, lignin oxidation products, <em>n</em>-alkanes, sterols, and triterpenoids) to quantify the relative contribution of leaves and roots of each plant taxon to bulk SOC in a mangrove-salt marsh ecotone in Apalachicola (Florida, USA). The shallow peaks of mangrove leaf biomarker (α-amyrin for <em>A. germinans</em>, taraxerol for <em>R. mangle</em>) suggested the deposition of mangrove leaf-OC over soil surface after the initial mangrove establishment, while the abundance of betulin and 3,5-dihydroxy benzoic acid in <em>A. germinans</em> and <em>R. mangle</em> deep soils, respectively, indicated subsurface contribution of mangrove root-OC, down to 45-cm depth. Based on mixing models, the principal source of SOC in mangrove habitats has shifted from <em>S. alterniflora</em> roots to mangrove roots. The total contribution of roots to the SOC pool in mangrove habitats was 69.0–86.1 %, highlighting that SOC was preferentially formed belowground. Interestingly, within ∼34 years after initial mangrove establishment, the majority (62.3–74.0 %) of SOC in mangrove habitats continues to be derived from pre-existing salt marshes. This emphasizes that comparing bulk SOC without considering their actual sources could result in an overestimation of the contribution of encroaching mangroves to SOC stocks.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"456 ","pages":"Article 117249"},"PeriodicalIF":5.6,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143645135","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of vegetation restoration on soil organic carbon on the Loess Plateau, China using a combined remote sensing and process-based modeling approach","authors":"Xianlei Fan ,&nbsp;Yunqiang Wang ,&nbsp;Ying Qu ,&nbsp;Edith Bai","doi":"10.1016/j.geoderma.2025.117260","DOIUrl":"10.1016/j.geoderma.2025.117260","url":null,"abstract":"<div><div>A series of vegetation restoration programs (VRPs) have been implemented on the Loess Plateau, China to increase vegetation cover and soil organic carbon (SOC) content. Here, we used a Coupled Litter-Soil (CLS) model to estimate the spatiotemporal distribution of SOC change (0–100 cm) on the VRPs areas on the Loess Plateau from the vegetation restoration starting to 2100. The vertical transport process of SOC along the profile was considered in the model. Due to the starting time of VRPs varied across different areas on the Loess Plateau, we detected the implementation areas and starting times of VRPs from remote sensing data to constrain the model. Results indicate that between the restoration starting and the year 2022, VRPs areas increased a total of 0.8 Pg C of SOC (0–100 cm), showing an increasing trend of SOC from northwest to southeast on the Loess Plateau, China. Under the business-as-usual scenario (2022), our model predicts that SOC will reach a steady-state after 150 years of VRPs implementation, with a potential SOC storage of 2.9 Pg C (0–100 cm). The differences in SOC density among different future climate scenarios (SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5) were non-significant. Our study provides a platform for combining remote sensing techniques and a process-based model to better estimate and predict SOC change after the implementation of an ecological restoration program.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"456 ","pages":"Article 117260"},"PeriodicalIF":5.6,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143642509","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The diversity, composition and potential function of bacterial size fractions from maize and soybean farmland soils","authors":"Xuemei Hu ,&nbsp;Chang Wang ,&nbsp;Siyuan Wang ,&nbsp;Yinghui Cao ,&nbsp;Haofei Zhang ,&nbsp;Chang Liu ,&nbsp;He Sun ,&nbsp;Yajun Gao ,&nbsp;Shanshan Yang ,&nbsp;Sanfeng Chen ,&nbsp;Sen Du ,&nbsp;Gehong Wei ,&nbsp;Weimin Chen","doi":"10.1016/j.geoderma.2025.117241","DOIUrl":"10.1016/j.geoderma.2025.117241","url":null,"abstract":"<div><div>Agricultural soil microbiomes, with their varied cell sizes and metabolic capabilities, contribute significantly to differences in soil ecosystem functions and services. However, the relationships among bacterial cell size, community structure and nutrient turnover in agricultural soils remain unclear. This study categorized bacterial cells from maize and soybean fields into five distinct size fractions—F1 (&gt;10 μm), F2 (3–10 μm), F3 (1–3 μm), F4 (0.4–1 μm) and F5 (0.2–0.4 μm)—using polycarbonate membrane filtration. High-throughput sequencing of the 16S rRNA gene and soil incubation subsequently revealed the taxonomic composition and potential functions of each size fraction. The results indicated that the bacterial diversity in maize field soil was greater than that in soybean field soil, with the F4 size fraction exhibiting the highest diversity and abundance in both soils, whereas the F1 size fraction showed the lowest. <em>Proteobacteria</em> dominated across all size fractions, and size-specific taxonomic distributions were observed: <em>Myxococcota</em>, <em>Entotheonellaeota</em> and <em>Cyanobacteria</em> were enriched in F1 and F2; <em>Planctomycetota</em> and <em>Chloroflexi</em> were enriched in F3; <em>Bacteroidota</em>, <em>Verrucomicrobiota</em>, <em>Actinobacteriota</em> and <em>Firmicutes</em> were enriched in F4 and F5. Before incubation, the qPCR of functional genes showed that the F1–F3 fractions exhibited highly active ammonia oxidation (F1, F2) and ammonification (F3), while the F4 fraction presented highly efficient organic P mineralization, when compared to other fractions. After incubation, qPCR and soil property analyses revealed that the F4 fraction exhibited highest increase in cell numbers and regulated C and P turnover through the secretion of BG and AKP, whereas the F1 fraction consistently maintained high ammonia oxidation capacity. These findings illustrate that bacterial taxa vary in cell size and nutrient turnover processes under different land-uses, thereby deepening our understanding of the bacterial ecology in farmlands.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"456 ","pages":"Article 117241"},"PeriodicalIF":5.6,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143636299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A novel perspective on near-surface soil freeze states: Discontinuity of the freeze process","authors":"Xiqiang Wang ,&nbsp;Rensheng Chen ,&nbsp;Chuntan Han ,&nbsp;Xueliang Wang","doi":"10.1016/j.geoderma.2025.117258","DOIUrl":"10.1016/j.geoderma.2025.117258","url":null,"abstract":"<div><div>The freeze state of near-surface soil is crucial for regional hydrology, ecosystems, and infrastructure, yet its discontinuous nature remains largely unknown. This research addresses this gap by employing soil temperatures at a depth of 5 cm from 335 meteorological stations across China, introducing three novel indicators—continuous freeze frequency, freeze fragmentation index, and freeze continuity index––to quantify freeze process discontinuity. The findings reveal significant regional variations in freeze discontinuity across China, primarily shaped by latitude. Further analysis reveals that snow depth can explain 27.3 % and 20.0 % of the variation in freeze continuity and continuous freeze frequency, respectively, while air temperature can account for 30.6 % of the variation in freeze fragmentation. The structural equation model suggests that precipitation, sunshine duration, and air temperature exert both direct and indirect effects on freeze discontinuity, and snow cover plays a key role in mediating the influence of other environmental variables on freeze discontinuity. This study offers a novel analytical perspective on the soil freeze state, enhancing our understanding of freeze dynamics under climate warming.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"456 ","pages":"Article 117258"},"PeriodicalIF":5.6,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143636298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ensemble and transfer learning of soil inorganic carbon with visible near-infrared spectra","authors":"Yu Wang ,&nbsp;Keyang Yin ,&nbsp;Bifeng Hu ,&nbsp;Yongsheng Hong ,&nbsp;Songchao Chen ,&nbsp;Jing Liu ,&nbsp;Lili Yang ,&nbsp;Jie Peng ,&nbsp;Zhou Shi","doi":"10.1016/j.geoderma.2025.117257","DOIUrl":"10.1016/j.geoderma.2025.117257","url":null,"abstract":"<div><div>Soil inorganic carbon (SIC) dominates the soil carbon pools in semi-arid and arid areas globally. Variations in the SIC pool would substantially affect the atmospheric CO₂ concentrations. The rapid and accurate measurement of SIC content using visible near-infrared (Vis-NIR) spectroscopy is of high significance for the management of soil carbon pools in semi-arid and arid regions. Ensemble learning is a novel and advanced modeling approach. However, it has been applied less in soil spectroscopy, and its transfer capability has not been evaluated. Therefore, we hypothesized that the use of the ensemble technique could further SIC prediction accuracy and have a better model transfer capability. In this study, a stacking model was developed using 990 soil samples collected from the Alar Reclamation region in South Xinjiang, China. The stacking model consists of 10 base models (support vector machine (SVM), partial least squares algorithm (PLSR), multi-layer perceptron (MLP), etc.). Two strategies (hyperparameter-adjusted and −unadjusted) were used to transfer the model to other target areas including Shaya and Wensu Counties on the southern border of China. Our results demonstrate that the SIC content could be predicted accurately using the stacking models (R²_p = 0.81). The stacking model outperformed all the individual models and significantly improved the prediction accuracy of SIC. The R²_p of the stacking models improved by 0.05–0.21, and the root mean square error (RMSE_P) reduced by 0.33–1.44 g kg⁻¹. Additionally, the stacking models displayed superior model transfer capability. Compared with direct transfer, the stacking model with fine-tuning of the hyperparameters displayed better model stability and generalization. Moreover, the average R²_p improved by over 0.09 compared with the stacking model with unadjusted hyperparameters. Overall, stacking ensemble learning is a potential method for predicting SIC with good transfer capabilities. Our results provide new tools and strategies for the accurate estimation of SIC in semi-arid and arid regions.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"456 ","pages":"Article 117257"},"PeriodicalIF":5.6,"publicationDate":"2025-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143628121","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Molybdenum regulates phosphorus cycling species diversity and improves soil phosphorus availability through key flavonoids in the soybean (Glycine max)","authors":"Xiaoming Qin ,&nbsp;Yining Liu ,&nbsp;Qingyun Xu ,&nbsp;Chengxiao Hu ,&nbsp;Songwei Wu ,&nbsp;Xuecheng Sun ,&nbsp;Qiling Tan","doi":"10.1016/j.geoderma.2025.117242","DOIUrl":"10.1016/j.geoderma.2025.117242","url":null,"abstract":"<div><div>Applying molybdenum (Mo) fertilizer can improve soil phosphorus (P) bioavailability, reduce the need for P fertilizers in agriculture, and enhance crop growth. However, the precise mechanisms behind these benefits are not yet fully understood. For the first time, we demonstrate the impact of Mo application on the transformation of P forms, metabolites, and microorganisms in the soybean rhizosphere. We carried out a series of pot experiments under controlled conditions, applying varying levels of Mo and collecting samples from the soybean rhizosphere across different treatments to analyze P forms, metabolic profiles, and microbial communities comprehensively. Mo application enhanced soybean P uptake and growth by promoted the conversion of aluminum-bound P (Al-P) and organic P to available P. The underlying mechanism involves the regulatory effect of Mo on the abundance of metabolites in the soil, thereby reshaping the structure of the rhizosphere microbial community. Two key Mo-mediated flavonoids, chrysin (Cs) and phlorizin (Pz), significantly promoted soybean growth and P absorption. Subsequently, Soil metagenomics and phosphate-solubilizing bacteria (PSB) addition experiments confirmed that these flavonoids increased P cycling genes (e.g., <em>gcd</em> and <em>phoD</em>) and microorganisms, facilitating stable P transformation into labile P, and aiding PSB (<em>Bacillus subtilis</em>) in further enhancing soil P availability. In summary, we have demonstrated for the first time that trace metals regulate the abundance of soil P cycling microorganisms by influencing crop-secreted flavonoids. This ultimately improves soil P bioavailability, providing a new insight for sustainable agricultural development.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"456 ","pages":"Article 117242"},"PeriodicalIF":5.6,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143621463","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nuclear magnetic resonance relaxometry to characterise the decomposition degree of peat soils","authors":"Stephan Costabel,&nbsp;Claus Florian Stange","doi":"10.1016/j.geoderma.2025.117244","DOIUrl":"10.1016/j.geoderma.2025.117244","url":null,"abstract":"<div><div>An adequate response to the ecological challenges associated with the traditional peatland management and corresponding site-specific measures require spatial information on soil properties and functions, most of which are related to the degree of peat decomposition. Our laboratory study tests the expectation that NMR relaxometry provides simple and rapidly available proxies characterising the decomposition state of peat. We observe that the mean NMR relaxation time is correlated with established soil physical parameters quantifying peat decomposition: water absorption index, unit water content, bulk density and von Post index. The higher the decomposition degree, the faster is the NMR relaxation, which mainly results from a decreasing pore space. Correlation maps between the T₁ and T₂ relaxation times identify hydrogel-like effects in weakly decomposed peat that vanishes if the material decomposes under aerobic conditions. T₁/T₂ ratios of more than ten are observed for peat material with cellular components in contrast to earthified topsoil peat with ratios of less than two. Our attempt to transfer the NMR relaxation data to estimates of water retention functions is partially successful. However, our results also indicate that the relaxation mechanisms in peat are not only controlled by pore sizes. We observe increasing surface relaxivities with increasing decomposition degree, which is most likely the result of a chemical transformation of the pore surface that alters its paramagnetic properties. The magnitude of this increase is significantly higher for T₁ than for T₂, because the interaction of water molecules and pore surface affects the corresponding NMR relaxation mechanisms differently.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"456 ","pages":"Article 117244"},"PeriodicalIF":5.6,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143628120","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Land use effects on soil carbon retention through glomalin-mediated aggregation","authors":"Ying Zhao ,&nbsp;Asim Biswas ,&nbsp;Mingtao Liu ,&nbsp;Xiaozeng Han ,&nbsp;Xinchun Lu ,&nbsp;Xu Chen ,&nbsp;Xiangxiang Hao ,&nbsp;Wenxiu Zou","doi":"10.1016/j.geoderma.2025.117252","DOIUrl":"10.1016/j.geoderma.2025.117252","url":null,"abstract":"<div><div>The glomalin-related soil protein (GRSP), produced by arbuscular mycorrhizal fungi, plays a critical role in soil organic carbon (SOC) storage and stabilization across terrestrial ecosystems. We examined the effects of four contrasting land-use types (bare land, cropland, grassland, and woodland) originating from the same soil matrix on GRSP dynamics, soil aggregation, and SOC accumulation. We found that grassland and woodland ecosystems exhibited significantly higher contents of macroaggregates (&gt;0.25 mm), SOC, total nitrogen (TN), total GRSP (TG), easily extractable GRSP (EEG) and aggregate stability compared with cropland and bare land. Across all land uses, the EEG/SOC and TG/SOC ratios in Mi and SC were higher than other aggregates sizes. Correlation analyses showed that TG was significantly and positively correlated with SOC in bulk soil and macroaggregates (&gt;2 mm), while EEG exhibited significant positive correlations with SOC in smaller macroaggregates and microaggregates. Furthermore, GRSP was strongly and positively correlated with aggregate stability, and the content of TG and the TG/SOC ratio were mainly influenced by microbial biomass carbon (MBC) and SOC. Our findings highlight the contrasting correlations of TG and EEG to SOC storage across aggregate size classes, with TG playing a more prominent role in bulk soil and large macroaggregates, and EEG more significantly associated with SOC accumulation in small macroaggregates and microaggregates. This study advances our understanding of the mechanisms by which GRSP facilitates SOC sequestration and soil aggregate formation under different land-use regimes, informing sustainable land management strategies for climate change mitigation.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"456 ","pages":"Article 117252"},"PeriodicalIF":5.6,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143621462","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In situ visualization of soil profile acidification and processes following nitrogen fertilization and liming","authors":"Jingjing Tao ,&nbsp;Lichao Fan ,&nbsp;Tao Jiang ,&nbsp;Xiaona Song ,&nbsp;Mengzhen Zhao ,&nbsp;Jianbin Zhou ,&nbsp;Yakov Kuzyakov ,&nbsp;Kazem Zamanian","doi":"10.1016/j.geoderma.2025.117243","DOIUrl":"10.1016/j.geoderma.2025.117243","url":null,"abstract":"<div><div>Soil pH is the master variable of soil properties and understanding its spatiotemporal changes <em>in situ</em> is key to unveiling numerous biogeochemical processes. The development of non-invasive imaging techniques provides the possibility to visualize and localize soil pH changes depending on various factors, e.g. fertilization and climate. Herein, the optodes pH mapping system was used to study the effects of eight fertilizer types including chicken manure, Ca(NO₃)₂, Mg(NO₃)₂, KNO₃, NH₄NO₃, (NH₄)₂SO₄, NH₄H₂PO₄, and urea on the spatiotemporal distribution of soil pH with and without liming at 10 °C and 25 °C. Ammonium-based fertilizers, especially NH₄NO₃, (NH₄)₂SO₄, and NH₄H₂PO₄ strongly decreased soil pH by a maximum of 1.4 ± 0.16 units at both temperatures. The 0–2 cm, where fertilizers were applied, had the highest pH decreases, from where the acidity rapidly diffused to depth. The acidified depth extended down to 4.5 ± 0.14 cm over 60 d. Chicken manure increased the pH within 5 d, but the pH decreased again after 60 d. Soil temperature was a strong controller of acidity generation and transport to depth after fertilization: pH decreased by 0.1 ± 0.07–0.3 ± 0.07 units more at 25 °C than 10 °C due to increased activity of nitrifying microorganisms, and higher temperature accelerated the spatiotemporal dynamics of soil acidity. Although pH increased shortly after liming compared to unlimed soils, it decreased after adding ammonium-based fertilizers. Therefore, N fertilizer types and temperature should be considered for having a more efficient fertilization management with less consequences for soil acidification. The planar optode is a powerful non-invasive imaging technique that enables <em>in situ</em> visualization of the spatiotemporal changes of soil pH profile after fertilization.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"456 ","pages":"Article 117243"},"PeriodicalIF":5.6,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143609988","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Biochar’s electron shuttle potential mitigates N2O emissions by counteracting the stimulatory effect of rice root iron plaque","authors":"Dan Yuan ,&nbsp;Sihuan Wu ,&nbsp;Chunsheng Hu ,&nbsp;Jiahuan Tang ,&nbsp;Shuping Qin","doi":"10.1016/j.geoderma.2025.117248","DOIUrl":"10.1016/j.geoderma.2025.117248","url":null,"abstract":"<div><div>Iron (Fe) plaque on rice roots can enhance nitrous oxide (N₂O) emissions from paddy soil, primarily through Fe(II) oxidation-coupled denitrification. In this study, our hypothesis is that biochar will reduce N₂O emissions via an electron shuttle and complete denitrification. To test this hypothesis, we performed laboratory microcosm experiments using a paddy soil-Fe plaque system amended with biochar. We examined the effects of biochar on soil N₂O emissions, soil microbial community composition, and denitrifying functional gene. Furthermore, we evaluated potential correlations between biochar’s electron shuttle capacity and N₂O emissions, as well as the N₂O/(N₂O + N₂) ratio derived from denitrification processes.</div><div>Our results demonstrated that, in the absence of rice straw biochar, N₂O emissions were doubled in the presence of Fe plaque. Interestingly, the addition of 1 % biochar to the paddy soil neutralized the difference in N₂O emissions between the Fe plaque and control treatments. Furthermore, biochar addition enhanced the abundance of Fe(II)-oxidizing denitrifiers (e.g., <em>Bacillus</em> and <em>Zoogloea</em>) at the genus level and upregulated key denitrification functional genes (e.g., <em>nirK</em> and <em>nosZ</em>) associated with N₂O mitigation. Importantly, oxidative treatment of biochar with H₂O₂ at varying concentrations reduced its electron donation capacity, which significantly weakened its ability to counteract Fe plaque-induced stimulation of N₂O emissions. This efficacy was directly proportional to the biochar’s electron transfer capabilities.</div><div>These results highlight the critical role of biochar’s electron transfer function in counteracting the stimulatory effect of Fe plaque on N₂O emissions. We conclude that adding biochar with strong electron transfer capabilities is a promising strategy to curb the Fe plaque-induced priming effect on N₂O emissions in paddy soils. The application of just 1 % biochar at the rice seedling stage may effectively mitigate N₂O emissions in paddy soils.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"456 ","pages":"Article 117248"},"PeriodicalIF":5.6,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143601063","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}