European Journal of Soil Science最新文献

{"title":"Soil Organic Carbon Stocks and Saturation Deficit in Mediterranean Olive Groves: Effects of Intensification and Management Practices","authors":"Víctor Valenzuela-Polo,&nbsp;Victoria Ochoa,&nbsp;Julio Calero,&nbsp;María Caridad Peñafiel-Suarez,&nbsp;Vasileios Gkisakis,&nbsp;Ioanna Michail,&nbsp;Emmanouil Kabourakis,&nbsp;Ioannis Zografakis,&nbsp;Thanasis Kizos,&nbsp;Giorgios Stavrianakis,&nbsp;Stratis Sentas,&nbsp;Rosolino Ingraffia,&nbsp;Alfonso S. Fenda,&nbsp;Aadil Bajoub,&nbsp;Francesca de Luca,&nbsp;Antonio J. Manzaneda","doi":"10.1111/ejss.70414","DOIUrl":"10.1111/ejss.70414","url":null,"abstract":"<p>Soil organic carbon (SOC) plays a critical role in climate regulation, particularly in agroecosystems where soil management practices significantly influence carbon sequestration. In the Mediterranean Basin, olive groves represent a major agricultural system whose carbon storage potential remains insufficiently characterized at large spatial scales. This study assessed SOC stocks and their saturation status in 52 olive orchards sampled across five Mediterranean countries (Spain, Greece, Italy, Portugal, and Morocco), with 39 orchards retained for stock calculations after quality control of bulk density and coarse fragment data. SOC was quantified by both dry combustion and the Nelson and Sommers wet oxidation method. Agreement between methods was formally tested, and a carbonate-dependent positive bias of the dry combustion method (<i>r</i> = +0.20 between ISO−NS difference and carbonate content, <i>p</i> &lt; 0.0001) led us to retain Nelson &amp; Sommers values for all stock calculations. Bulk density measured with Kopecky cylinders was retained over a Saxton &amp; Rawls pedotransfer estimate after a paired comparison showed poor concordance (Lin's CCC = 0.08; 95% LoA = ±0.5 g cm⁻³). The maximum SOC saturation limit (SOC_max) was estimated from the silt + clay protective fraction, with consistent (1−FG) coarse-fragment correction applied to both current and maximum stocks so that the saturation deficit (SOC_potential = SOC_max−SOC_current) is a directly comparable, physically meaningful gap. Multivariate analyses (PCA, LDA with Wilks' Λ, two-way PERMANOVA) revealed that olive orchards are organized along a single dominant intensification gradient (PC1, 30.5% of variance; CD1, 91.7% of canonical variance, <i>p</i> &lt; 0.001) rather than into separable agronomic management classes; the gradient is robust to the exclusion of operationally tautological variables. Mediterranean olive groves operated on average at 41% of their textural carbon-storage capacity, with a mean saturation deficit of 64 Mg C ha⁻¹ (59% of SOC_max). The deficit varied along the intensification axis in the direction predicted by carbon-saturation theory (saturation level: 49% organic, 39% conventional, 33% high-density), although per-group differences did not reach significance with <i>n</i> = 9–12 orchards per management class. Super-intensive (hedgerow) systems with &gt; 1000 trees ha⁻¹ were not represented in the sample, and this is acknowledged as a limitation. These findings highlight that intensification, more than the organic-versus-conventional dichotomy, structures the multivariate variability of Mediterranean olive groves, and that current SOC stocks lie well below textural saturation in most systems, indicating substantial potential for additional carbon sequestration through soil-conservation practices.</p>","PeriodicalId":12043,"journal":{"name":"European Journal of Soil Science","volume":"77 5","pages":""},"PeriodicalIF":4.3,"publicationDate":"2026-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/ejss.70414","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148860922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"Long-Term Impact of Cropping System and Nitrogen Input Quality on Nitrogen Release and Organic Matter Chemistry","authors":"Sevendeep Kaur Chahal,&nbsp;BaoLuo Ma,&nbsp;John Lauzon,&nbsp;Joshua Nasielski,&nbsp;Adam W. Gillespie","doi":"10.1111/ejss.70401","DOIUrl":"10.1111/ejss.70401","url":null,"abstract":"<p>Long-term integrated soil management strategies are essential for enhancing soil organic matter (SOM) quality and promoting the availability of mineralizable nitrogen (N). This study employed a tripartite analytical framework to investigate how crop rotations and organic N amendments influence soil N availability and SOM chemistry. A twelve-week incubation assay quantified potentially mineralizable nitrogen (Min N) across five cropping systems: continuous corn (CC), continuous soybean (Soy), continuous clover (Cl), corn-soybean (CS), and corn-clover (CCl), under four N fertility regimes: no N input (N0), synthetic N as Urea (NF), uncomposted manure (UCM), and composted manure (CM). To evaluate the chemical stability of soil N, pyrolysis was used to calculate NH₃-T50 (the temperature at which 50% of ammonia is released), serving as an indicator of thermal N stability. In parallel, X-ray Absorption Near Edge Structure (XANES) spectroscopy characterized the chemical speciation of carbon and N in SOM. The Min N assay revealed significantly enhanced N availability in legume-inclusive systems, particularly Cl and CCl treatment amended with CM or UCM. The NH₃-T50 exhibited a significant negative correlation with Min N, indicating that more labile, biologically accessible N forms are associated with lower thermal stability. The XANES spectroscopy suggested that CC systems were characterized by amide and pyrrole N structures: markers of proteinaceous residues and limited microbial decomposition. In contrast, CCl treatments were enriched with pyridinic, aromatic, and aliphatic compounds, indicative of advanced microbial processing and stabilization pathways. Notably, UCM and CM treatments clustered closely in multivariate space, suggesting comparable SOM transformation trajectories despite compost maturity differences. Divergence in SOM chemistry under NF and N0 treatments reflected shifts toward labile or recalcitrant N pools, modulated by rotation context and input type. These findings highlight that integrating legumes and organic N amendments fosters a more microbially accessible soil N pool while supporting the development of chemically complex and stable SOM. The combined use of Min N assays, thermal analysis, and molecular spectroscopy provides a robust framework for understanding the interactions between crop rotation, N management, and SOM quality in sustainable agroecosystems.</p>","PeriodicalId":12043,"journal":{"name":"European Journal of Soil Science","volume":"77 5","pages":""},"PeriodicalIF":4.3,"publicationDate":"2026-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/ejss.70401","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148861066","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"Lower Carbon but Higher Mesofauna β-Diversity Under Bracken in Open Habitats Not Indicative of Woodland Soil: Case Study","authors":"Jake Freddie Spong,&nbsp;Aidan M. Keith,&nbsp;Ashley Lyons,&nbsp;Mo A. Verhoeven,&nbsp;Robert T. E. Mills","doi":"10.1111/ejss.70407","DOIUrl":"10.1111/ejss.70407","url":null,"abstract":"<div>\u0000 \u0000 <p>Bracken (<i>Pteridium aquilinum</i>) is of major concern to land managers due to its ability to invade grassland and heathland systems, but it is believed to indicate where woodland once was or where conditions may be favourable for woodland in the future. The effects of bracken on the soil system are also not well understood despite the key role of soils in carbon and nutrient cycling and as one of the most biodiverse habitats on the planet. Whilst soil mesofauna are amongst the most abundant animals and present at multiple trophic levels in the soil food web, the importance of their diversity remains underappreciated and overlooked in policy and land management. Due to their role in litter decomposition, mesofauna should be explored in light of the conspicuous shift in litter form and quantity when bracken is present. In this study, soil mites, springtails, nematodes and soil properties in grassland and heathland were compared to those in woodland in the presence and absence of bracken to ascertain whether these communities could provide useful detail for potential woodland restoration. Under bracken soils, total and water-extractable organic carbon, water-extractable nitrogen, C:N ratios, Zn²⁺ concentrations and mesofauna abundances were lower. Reductions in microinvertebrate α-diversity under bracken were specific to heathland only, whilst β-diversity in grassland and heathland was enhanced under bracken by increased morphotype turnover. These results indicate that soil nutrients and communities under bracken do not represent a shift towards those found in woodland soils and are more strongly driven by ecosystem type than plant species composition or the presence of bracken. Future work should investigate whether bracken is causing the observed differences in soil nutrients and community structure, focusing on possible mechanistic drivers such as changes in bacterial-fungal ratios and microbial activity.</p>\u0000 </div>","PeriodicalId":12043,"journal":{"name":"European Journal of Soil Science","volume":"77 5","pages":""},"PeriodicalIF":4.3,"publicationDate":"2026-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148842942","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"What Co-Occurrence Networks Can and Cannot Tell Us About Soil Ecology","authors":"S. Emilia Hannula,&nbsp;Sophie J. Planchenault,&nbsp;Elaine Haskins,&nbsp;Tancredi Caruso","doi":"10.1111/ejss.70397","DOIUrl":"10.1111/ejss.70397","url":null,"abstract":"<div>\u0000 \u0000 <p>Co-occurrence network analyses are widely used to explore soil microbial communities, providing a framework to describe associations among soil taxa and their potential responses to environmental gradients or treatments. These networks are often interpreted as representations of ecological interactions yet, the ecological (and statistical) robustness of such inferences depends on whether the network in question truly reflects underlying biological associations rather than just spurious correlations or even methodological artifacts. In this opinion paper, we examine the premise, strengths, and limitations of co-occurrence network analyses and discuss methodological challenges associated with data compositionality, sample size, taxonomic resolution, and the spatial and temporal scales at which interactions occur in soil. We highlight the importance of robust null models for statistical validation of network patterns to identify genuine structures and their ecological implications. We finally synthesize approaches for integration between network science and soil ecology to enable co-occurrence networks move from descriptive analyses to understanding the mechanisms that structure soil biodiversity and ecosystem functioning.</p>\u0000 </div>","PeriodicalId":12043,"journal":{"name":"European Journal of Soil Science","volume":"77 5","pages":""},"PeriodicalIF":4.3,"publicationDate":"2026-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148842841","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Towards Healthier Soils: Insights for Knowledge Building, Co-Creation and Citizen Engagement in Soil Science","authors":"Alba Peiro,&nbsp;Claudia Cappello,&nbsp;Silvana Munzi,&nbsp;Roy Neilson,&nbsp;Céline Laurent,&nbsp;Francisco Sanz,&nbsp;Tanja Mimmo","doi":"10.1111/ejss.70409","DOIUrl":"10.1111/ejss.70409","url":null,"abstract":"<div>\u0000 \u0000 <p>Soil health underpins essential ecosystem functions and the delivery of multiple societal benefits, yet it is increasingly threatened by widespread soil degradation driven by both natural and anthropogenic processes. This environmental challenge is further exacerbated by limited public awareness of the societal importance of soil, a key non-renewable resource. Citizen science offers a participatory approach to addressing this challenge by engaging members of the public in soil research, strengthening their soil literacy, knowledge, and skills that enable the co-creation of a robust evidence base to inform future policies and practices. Here, we present practical insights into citizen science methodologies for assessing, monitoring, and mapping soil health, with particular emphasis on engagement design and implementation. We review recent soil-related citizen science projects, identifying their respective strengths and limitations. Building on these findings, we apply an assessment framework to select the most suitable methodologies for involving citizens in soil sampling within a Europe-wide initiative designed to measure eight soil health indicators through both field observations and laboratory analyses. While data contribution remains the most common form of participation in large-scale citizen soil initiatives, we also highlight strategies to support citizen involvement in the refinement and co-design of materials and activities, as well as in local leadership roles through Ambassador networks. Drawing on these insights, we have designed and are currently implementing nine national citizen science initiatives aimed at fostering soil literacy. In these initiatives, participants use comprehensive field protocols and a dedicated toolkit to contribute soil data to an open-access repository. Together, these experiences demonstrate the potential of citizen science to support the generation of soil health data and the societal engagement needed to advance sustainable soil management.</p>\u0000 </div>","PeriodicalId":12043,"journal":{"name":"European Journal of Soil Science","volume":"77 5","pages":""},"PeriodicalIF":4.3,"publicationDate":"2026-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148842836","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Correction to ‘Evaluation of the Effect of Aeration Tubes and Holes on Soil Gas Exchange Using a Simulation Model’","authors":"","doi":"10.1111/ejss.70408","DOIUrl":"https://doi.org/10.1111/ejss.70408","url":null,"abstract":"<p>\u0000 <span>Weltecke, K.</span>, <span>Löwe, O.</span> and <span>Gaertig, T.</span> (<span>2025</span>), <span>Evaluation of the Effect of Aeration Tubes and Holes on Soil Gas Exchange Using a Simulation Model</span>. <i>European Journal of Soil Science</i>, <span>76</span>: e70051. https://bsssjournals.onlinelibrary.wiley.com/doi/10.1111/ejss.70051\u0000 </p><p>In Figure 14 caption, ‘CO2 profile of sealed soils with and without aeration layer (soil air-filled porosity: 0.15 m3 m−3, distance to centre: 1.25 m),’ the correct value should be 0.1 m³ m⁻³, distance to centre: 1.25 m.</p><p>This does not affect the conclusion or the text of the article.</p><p>We apologize for this error.</p>","PeriodicalId":12043,"journal":{"name":"European Journal of Soil Science","volume":"77 5","pages":""},"PeriodicalIF":4.3,"publicationDate":"2026-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/ejss.70408","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148807788","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"Scale-Dependent Limitations of the Mehlich 3 Method in Paddy Soils in Japan: Toward Standardized Soil Testing","authors":"Miku Ikeda,&nbsp;Atsushi Nakao,&nbsp;Takuro Shinano,&nbsp;Shigeto Fujimura,&nbsp;Thomas Chalaux-Clergue,&nbsp;Junta Yanai","doi":"10.1111/ejss.70406","DOIUrl":"https://doi.org/10.1111/ejss.70406","url":null,"abstract":"<div>\u0000 \u0000 <p>The Mehlich 3 (M3) method is one of the most widely used universal extractants for multielement soil testing of nutrient availability, yet its performance across spatial scales that encompass diverse pedogenic contexts remains unclear. To assess the comparability of the Mehlich 3 method with conventional extraction methods across contrasting pedogenic contexts, M3 extraction was compared with conventionally extracted nutrient contents for 10 elements (Ca, Mg, K, P, Mn, Zn, Ni, Fe, Cu, and Si) in paddy soils collected across three spatial scales (local, regional, and national) in Japan. Regardless of spatial scale, the M3 method showed comparable extracted amounts to conventional methods for Ca, Mg, K, Mn, Zn, and Ni, thereby confirming its reliability as a universal extractant. Regarding P, the extracted amounts of M3 were about half those of Bray 2 and about twice those of Truog. Furthermore, the correlation coefficient between M3 and these conventional methods for P decreased at broader spatial scales, including soils with variable amorphous Fe/Al (hydr)oxide content. The present results demonstrate that the M3 method provides robust and scalable estimates for most nutrients, while also revealing that its performance for P is sensitive to pedogenic variability. This highlights the importance of incorporating pedogenic context when defining M3 applicability domains, particularly for P assessment, thereby improving the comparability of soil testing results across small- and large-scale soil monitoring frameworks.</p>\u0000 </div>","PeriodicalId":12043,"journal":{"name":"European Journal of Soil Science","volume":"77 5","pages":""},"PeriodicalIF":4.3,"publicationDate":"2026-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148807786","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mechanisms Explaining Increasing Soil Water Repellency With Water Content Below the Permanent Wilting Point: A Review","authors":"E. V. S. Wong,&nbsp;P. R. Ward,&nbsp;M. Leopold,&nbsp;D. V. Murphy,&nbsp;L. Barton","doi":"10.1111/ejss.70405","DOIUrl":"https://doi.org/10.1111/ejss.70405","url":null,"abstract":"<p>Soil water repellency (SWR) often displays a non-linear relationship with soil water content (SWC) below the permanent wilting point (−1500 kPa or pF 4.2). Rather than declining as soils wet, SWR frequently intensifies as SWC increases from oven-dry conditions to the permanent wilting point (or extremely dry range), reaching a peak before collapsing at SWC greater than the permanent wilting point. Several mechanisms based on pore-blocking or porosity-based processes, transitions from Cassie-Baxter to Wenzel states and soil microbial activity have been proposed to explain this behaviour; yet, none provide quantitative support for the observed changes in SWR under dry soil conditions. This review synthesises empirical observations for SWR behaviour in the extremely dry range and examines the physicochemical processes directly relevant to explaining its intensification with increasing SWC. The hydration and evolution of interfacial water films on hydrophilic, hydrophobic and heterogeneous non-soil surfaces are examined to provide insight into how water vapour is adsorbed on the surfaces of water-repellent soil particles, where its interfacial water film is particularly complicated if salts and organic compounds are present. The synthesis shows that the increase in SWR coincides with the onset of capillary condensation and the transition of adsorbed water from rigid, ice-like interfacial layers to more mobile, liquid-like thin films. Within this narrow hydration regime, ionic redistribution and hydration-dependent reorientation of amphiphilic organic compounds modify interfacial configurations without producing continuous wetting, thereby amplifying apparent hydrophobics. By integrating adsorption behaviour with existing evidence on surface free energy in heterogeneous soil systems, this review establishes a physicochemical basis for evaluating existing hypotheses and developing a coherent mechanistic explanation for the SWR-SWC relationships under dry soil conditions.</p>","PeriodicalId":12043,"journal":{"name":"European Journal of Soil Science","volume":"77 5","pages":""},"PeriodicalIF":4.3,"publicationDate":"2026-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/ejss.70405","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148807787","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 Soil Profile Dataset From Central Ethiopia: Morphological, Physical and Chemical Properties, WRB Classification, and Root Count","authors":"Musefa A. Redi,&nbsp;Johan G. B. Leenaars,&nbsp;Stephan Mantel,&nbsp;Gerard B. M. Heuvelink","doi":"10.1111/ejss.70402","DOIUrl":"10.1111/ejss.70402","url":null,"abstract":"<p>Comprehensive soil profile datasets are essential for understanding and modelling soil and soil processes, yet remain scarce in Sub-Saharan Africa. This is particularly true for full soil profiles combining root observations with soil water retention characteristics. Here, we present a dataset of 50 soil profiles from maize and wheat systems in central Ethiopia, comprising observations and measurements from soil pits described and sampled to depths of down to 2 m. The dataset integrates pedogenic horizons with morphological descriptions, detailed root distribution observations, and analytical data for physical and chemical soil properties obtained from fixed sampling layers. All profiles are classified according to the World Reference Base for Soil Resources. Field photographs are included to document soil morphology and field procedures. The dataset may support improved understanding and modelling of soil processes, soil hydrology, and the relationship between crop roots, soil morphology, and soil properties. It may also support applications in digital soil mapping, and the development of pedotransfer functions. The dataset is publicly accessible in the PANGAEA repository at https://doi.pangaea.de/10.1594/PANGAEA.995660.</p>","PeriodicalId":12043,"journal":{"name":"European Journal of Soil Science","volume":"77 4","pages":""},"PeriodicalIF":4.3,"publicationDate":"2026-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/ejss.70402","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148767293","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"Nitrate Thresholds Control Regime Shifts in Soil Nitrogen Cycling Across a Mangrove–Agricultural Gradient","authors":"Mathieu Sebilo, Bastien Redon, Elona Ousselin, Mélanie Longchamp, Lynda Chalder, Anaelle Devarieux, Patrick Jean‐Louis, Olivier Gros","doi":"10.1111/ejss.70396","DOIUrl":"https://doi.org/10.1111/ejss.70396","url":null,"abstract":"Anthropogenic nitrogen inputs are increasing globally, while the conditions under which ecosystems transition from nitrogen retention to nitrogen loss remain poorly constrained. Environmental proxies commonly used to infer nitrogen loss, including redox status, carbon availability, and microbial gene inventories, provide limited power to predict when nitrate‐reduction pathways are expressed at the ecosystem scale. This limitation is particularly evident in coastal mangrove soils, where anaerobic and carbon‐rich conditions coexist with weak nitrate‐reduction activity. Here, we investigate nitrogen‐cycle organization along a spatially compressed mangrove–agricultural gradient on a Caribbean island by combining soil nitrogen pools, organic nitrogen isotopes (δ <jats:sup>15</jats:sup> N), inferred microbial metabolic functions putatively related to the microbial community (16S rDNA metabarcoding analysis), and controlled anoxic nitrate‐amended incubations. Across distances of less than 500 m, soils transitioned sharply from nitrogen‐rich, isotopically depleted mangrove sediments (total N up to 1.4%; δ <jats:sup>15</jats:sup> N≈2‰–3‰) to nitrogen‐poor, isotopically enriched agricultural soils (total N≈0.2%–0.6%; δ <jats:sup>15</jats:sup> N≈6‰–8‰). Despite widespread microbial functional potential associated with nitrate reduction throughout the transect, nitrate depletion under anoxic conditions remained slow in mangrove and back‐mangrove soils (0.56–1.15 nmol g <jats:sup>−1</jats:sup> min <jats:sup>−1</jats:sup> ) but was more than threefold faster in agricultural soils (2.32 nmol g <jats:sup>−1</jats:sup> min <jats:sup>−1</jats:sup> ). To integrate these long‐term isotopic and stoichiometric signals, we developed the Organic Nitrogen Index coupled to soil C/N ratios (ONI‐CN), an isotopic–stoichiometric framework combining δ <jats:sup>15</jats:sup> N and soil C/N ratios. Along the studied transects, ONI‐CN captured a sharp transition between two nitrogen‐cycle configurations, with mangrove and back‐mangrove soils clustering within a closed, recycling‐dominated state and agricultural soils in an open, loss‐dominated state, with no intermediate values. These observations support the interpretation that nitrate availability constrains the long‐term expression of nitrate‐loss pathways across the mangrove–agricultural gradient. The results are consistent with the presence of a functional nitrogen bank in mangrove soils, in which microbial nitrate reduction potential remains weakly expressed under chronically nitrate‐limited conditions. This framework highlights the sensitivity of nitrogen‐limited coastal ecosystems to increasing anthropogenic nitrate inputs and provides a conceptual basis for understanding threshold‐like reorganizations of nitrogen cycling under environmental changes.","PeriodicalId":12043,"journal":{"name":"European Journal of Soil Science","volume":"93 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2026-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148767291","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}