Pub Date : 2026-02-10DOI: 10.1016/j.geoderma.2026.117723
Jonathan Y. Lin , Daoyuan Wang , Cameron K. McMillan , King C. Law , Kate M. Scow , Jorge L. Mazza Rodrigues
Microorganisms live in communities within and on the surface of soil aggregates of varying sizes. A growing body of evidence suggests that different size fractions of aggregates are habitats for distinct microbial communities, but comparisons have been difficult owing to different aggregate separation methods. Two aggregate isolation methods, dry and wet sieving, originating from field moist and dried soils were used to investigate their effects on the prokaryotic and fungal communities in four aggregate size fractions (large macroaggregates (>2000 μm), small macroaggregates (250–2000 μm), microaggregates (53–250 μm), and silt & clay (<53 μm)) using metabarcoding of the 16S rRNA gene and internal transcribed spacer. While prokaryotic community composition among treatments in each of the four size fractions was different, the composition and alpha diversity for fungi were more resistant to change in large and small macroaggregates than in the microaggregate and silt & clay fractions. The average prokaryotic ribosomal RNA copy number and genome size increased in all aggregate size fractions when soils were dried before sieving. Decisions on which aggregate separation method to use depend heavily on the questions one is interested in, but soil storage conditions between sample collection and sieving are highlighted as driving the biggest differences in microbial community composition.
{"title":"Differential responses of prokaryotic and fungal communities in soil microenvironments to drying and wetting as affected by soil aggregate isolation method","authors":"Jonathan Y. Lin , Daoyuan Wang , Cameron K. McMillan , King C. Law , Kate M. Scow , Jorge L. Mazza Rodrigues","doi":"10.1016/j.geoderma.2026.117723","DOIUrl":"10.1016/j.geoderma.2026.117723","url":null,"abstract":"<div><div>Microorganisms live in communities within and on the surface of soil aggregates of varying sizes. A growing body of evidence suggests that different size fractions of aggregates are habitats for distinct microbial communities, but comparisons have been difficult owing to different aggregate separation methods. Two aggregate isolation methods, dry and wet sieving, originating from field moist and dried soils were used to investigate their effects on the prokaryotic and fungal communities in four aggregate size fractions (large macroaggregates (>2000 μm), small macroaggregates (250–2000 μm), microaggregates (53–250 μm), and silt & clay (<53 μm)) using metabarcoding of the 16S rRNA gene and internal transcribed spacer. While prokaryotic community composition among treatments in each of the four size fractions was different, the composition and alpha diversity for fungi were more resistant to change in large and small macroaggregates than in the microaggregate and silt & clay fractions. The average prokaryotic ribosomal RNA copy number and genome size increased in all aggregate size fractions when soils were dried before sieving. Decisions on which aggregate separation method to use depend heavily on the questions one is interested in, but soil storage conditions between sample collection and sieving are highlighted as driving the biggest differences in microbial community composition.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"467 ","pages":"Article 117723"},"PeriodicalIF":6.6,"publicationDate":"2026-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146152898","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}
Pub Date : 2026-02-10DOI: 10.1016/j.geoderma.2026.117718
Yang Luo, Yaoli Su, Minghui Huang, Yang Li, Dehua Xu, Zhengjuan Yan, Xinlong Wang
The effects of ammonium polyphosphate (APP, (NH4)n+2PnO3n+1, n < 20) on soil phosphorus (P) availability vary depending on polymerization distributions and the soil type, yet the mechanisms driving these differences remain unclear. This study explored the availability and transformation of P affected by APP1 (P species of P1-P2) and APP2 (P species of P1-P7) in two different soils, in comparison with conventional ammonium phosphates (APs). APP application increased Olsen-P by 10.7–24.8% in calcareous soil, but decreased it by 2.6–10.8% in acid soil relative to APs. In calcareous soil, APP significantly increased soluble-P, adsorbed-P, and Fe-associated P, as reflected by CaCl2, NaHCO3, and NaOH extractable Ps, while decreased more stable Ca-associated P and occluded P indicated by NH4Ac and Na3C6H5O7-Na2S2O4-NaOH extractable Ps. The changes in the composition of CaCO3 and Fe/Al oxides together with/without the reduced organic carbon loss mainly contributed to the decrease in P sorption/precipitation and the increase in P desorption/dissolution. In acid soil, APP significantly increased microbial biomass P, leading to reduced labile inorganic P and elevated labile organic P. Meanwhile, APP increased both oxalate-extractable and complex Fe/Al oxides, which affected P adsorption–desorption to a certain extent. Compared to APP1, APP2 resulted in P existing in a more labile adsorbed state, thereby increasing P availability in both calcareous and acid soils. The main processes affecting P availability in the calcareous soils were abiotic transformations, while biotic transformations played the key role in the acid soils.
{"title":"Different mechanisms of phosphorus transformation in calcareous and acid soils affected by ammonium polyphosphate","authors":"Yang Luo, Yaoli Su, Minghui Huang, Yang Li, Dehua Xu, Zhengjuan Yan, Xinlong Wang","doi":"10.1016/j.geoderma.2026.117718","DOIUrl":"10.1016/j.geoderma.2026.117718","url":null,"abstract":"<div><div>The effects of ammonium polyphosphate (APP, (NH<sub>4</sub>)<sub>n+2</sub>P<sub>n</sub>O<sub>3n+1</sub>, n < 20) on soil phosphorus (P) availability vary depending on polymerization distributions and the soil type, yet the mechanisms driving these differences remain unclear. This study explored the availability and transformation of P affected by APP1 (P species of P<sub>1</sub>-P<sub>2</sub>) and APP2 (P species of P<sub>1</sub>-P<sub>7</sub>) in two different soils, in comparison with conventional ammonium phosphates (APs). APP application increased Olsen-P by 10.7–24.8% in calcareous soil, but decreased it by 2.6–10.8% in acid soil relative to APs. In calcareous soil, APP significantly increased soluble-P, adsorbed-P, and Fe-associated P, as reflected by CaCl<sub>2</sub>, NaHCO<sub>3</sub>, and NaOH extractable Ps, while decreased more stable Ca-associated P and occluded P indicated by NH<sub>4</sub>Ac and Na<sub>3</sub>C<sub>6</sub>H<sub>5</sub>O<sub>7</sub>-Na<sub>2</sub>S<sub>2</sub>O<sub>4</sub>-NaOH extractable Ps. The changes in the composition of CaCO<sub>3</sub> and Fe/Al oxides together with/without the reduced organic carbon loss mainly contributed to the decrease in P sorption/precipitation and the increase in P desorption/dissolution. In acid soil, APP significantly increased microbial biomass P, leading to reduced labile inorganic P and elevated labile organic P. Meanwhile, APP increased both oxalate-extractable and complex Fe/Al oxides, which affected P adsorption–desorption to a certain extent. Compared to APP1, APP2 resulted in P existing in a more labile adsorbed state, thereby increasing P availability in both calcareous and acid soils. The main processes affecting P availability in the calcareous soils were abiotic transformations, while biotic transformations played the key role in the acid soils.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"467 ","pages":"Article 117718"},"PeriodicalIF":6.6,"publicationDate":"2026-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146146753","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}
Pub Date : 2026-02-07DOI: 10.1016/j.geoderma.2026.117716
Juan Liu , Timothy Clough , Sam Carrick , Jiafa Luo , Andriy Podolyan , Naomi Wells , Chris Chisholm , Jupei Shen , Peng Li , Lianfeng Du , Hong Pan , Limei Zhang , Hong J. Di
Nitrous oxide (N2O) is a potent greenhouse gas predominantly emitted from grazed pasture through denitrification, driven by soil oxygen (O2) availability and urine-derived nitrogen (N). Pasture soils are vulnerable to compaction from animal treading, restricting gas diffusion and enhancing N2O emissions. Although subsoiling alleviates compaction, its impact on soil O2 status and N2O emissions, particularly under high urine N load, remain poorly understood and rarely investigated. This in-situ field study (March-August 2023) evaluated the effect of subsoiling on soil moisture, O2 content, relative gas diffusivity (Dp/Do), functional gene abundance, N2O emissions, and pasture production. Treatments included non-subsoiling or subsoiling, each with or without synthetic ruminant urine (713 kg N ha−1). Subsoiling improved macroporosity, enhanced O2 availability, increased Dp/Do at 5, 10 and 20 cm depth (P < 0.001), and reduced moisture at 10 cm depth (P < 0.001). Subsoiling significantly reduced N2O emissions by 52% and 81% of non-subsoiled plots for non-urine and urine treatments, respectively (P < 0.05). Dp/Do was strongly correlated with N2O fluxes during the first 15 days following urine application (R2 = 0.59–0.87), suggesting its utility as a predictive indicator under high substrate availability. Molecular analysis showed reduced nirK gene abundance under subsoiling, with limited response for other denitrification genes. Subsoiling had no significant effect on pasture yield or N uptake. Overall, subsoiling mitigates N2O emissions by improving soil aeration and Dp/Do while maintaining productivity, offering a promising strategy for sustainable N management in grazed pasture soils.
一氧化二氮（N2O）是一种强效温室气体，主要由放牧牧场通过反硝化作用排放，受土壤氧（O2）有效性和尿源性氮(N)的驱动。牧草土壤容易被动物踩踏压实，限制气体扩散，增加N2O排放。虽然沉土缓解了压实，但其对土壤O2状态和N2O排放的影响，特别是在高尿氮负荷下，仍然知之甚少，很少研究。本研究（2023年3月- 8月）评估了深埋对土壤水分、O2含量、相对气体扩散系数（Dp/Do）、功能基因丰度、N2O排放和牧草产量的影响。处理包括不渗土或渗土，分别添加或不添加合成反刍动物尿液（713 kg N ha−1）。沉土改善了宏观孔隙度，增强了O2有效性，增加了5、10和20 cm深度的Dp/Do (P < 0.001)，降低了10 cm深度的水分（P < 0.001）。在不排尿和排尿处理中，未排尿地块的N2O排放量分别显著减少52%和81% （P < 0.05）。Dp/Do与尿液应用后15天内N2O通量密切相关（R2 = 0.59-0.87），表明其在高底物利用率下可作为预测指标。分子分析表明，土壤深埋降低了nirK基因的丰度，对其他反硝化基因的响应有限。深耕对牧草产量和氮素吸收无显著影响。总体而言，深埋土壤通过改善土壤通气和Dp/Do来减少N2O排放，同时保持生产力，为放牧草地土壤的可持续氮管理提供了一种有希望的策略。
{"title":"Subsoiling reduces N2O emissions by altering the relative gas diffusivity, O2 status and microbial communities in grazed pasture soil","authors":"Juan Liu , Timothy Clough , Sam Carrick , Jiafa Luo , Andriy Podolyan , Naomi Wells , Chris Chisholm , Jupei Shen , Peng Li , Lianfeng Du , Hong Pan , Limei Zhang , Hong J. Di","doi":"10.1016/j.geoderma.2026.117716","DOIUrl":"10.1016/j.geoderma.2026.117716","url":null,"abstract":"<div><div>Nitrous oxide (N<sub>2</sub>O) is a potent greenhouse gas predominantly emitted from grazed pasture through denitrification, driven by soil oxygen (O<sub>2</sub>) availability and urine-derived nitrogen (N). Pasture soils are vulnerable to compaction from animal treading, restricting gas diffusion and enhancing N<sub>2</sub>O emissions. Although subsoiling alleviates compaction, its impact on soil O<sub>2</sub> status and N<sub>2</sub>O emissions, particularly under high urine N load, remain poorly understood and rarely investigated. This in-situ field study (March-August 2023) evaluated the effect of subsoiling on soil moisture, O<sub>2</sub> content, relative gas diffusivity (D<sub>p</sub>/D<sub>o</sub>), functional gene abundance, N<sub>2</sub>O emissions, and pasture production. Treatments included non-subsoiling or subsoiling, each with or without synthetic ruminant urine (713 kg N ha<sup>−1</sup>). Subsoiling improved macroporosity, enhanced O<sub>2</sub> availability, increased D<sub>p</sub>/D<sub>o</sub> at 5, 10 and 20 cm depth (<em>P < 0.001</em>), and reduced moisture at 10 cm depth (<em>P < 0.001</em>). Subsoiling significantly reduced N<sub>2</sub>O emissions by 52% and 81% of non-subsoiled plots for non-urine and urine treatments, respectively (<em>P < 0.05</em>). D<sub>p</sub>/D<sub>o</sub> was strongly correlated with N<sub>2</sub>O fluxes during the first 15 days following urine application (<em>R<sup>2</sup> = 0.59</em>–<em>0.87</em>), suggesting its utility as a predictive indicator under high substrate availability. Molecular analysis showed reduced <em>nirK</em> gene abundance under subsoiling, with limited response for other denitrification genes. Subsoiling had no significant effect on pasture yield or N uptake. Overall, subsoiling mitigates N<sub>2</sub>O emissions by improving soil aeration and D<sub>p</sub>/D<sub>o</sub> while maintaining productivity, offering a promising strategy for sustainable N management in grazed pasture soils.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"467 ","pages":"Article 117716"},"PeriodicalIF":6.6,"publicationDate":"2026-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146134156","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}
Pub Date : 2026-02-07DOI: 10.1016/j.geoderma.2026.117710
Liangyi Li , Zipeng Zhang , Minglu Sun , Jianli Ding , Jingzhe Wang , Dong Xu , Yuanyuan Huang
Addressing the dual challenges of limited sample size and high environmental heterogeneity in small-scale soil organic carbon (SOC) spectral modeling, this study proposes a fundamental hypothesis: selecting samples that are similar to the target region in both “spectral features and environmental characteristics” is more effective for improving prediction accuracy and stability. Based on this assumption, we developed a synergistic sample transfer strategy that integrates spectral similarity with environmental similarity under the Third Law of Geography, aiming to systematically screen the most comparable samples from the global soil spectral library to enhance the performance and robustness of local SOC modeling. A spectral-environmental similarity framework was established to identify samples that are simultaneously similar to the target region in spectral properties and environmental settings, and instance-based transfer modeling experiments were conducted in five representative small-sample regions (A-E). Results show that the synergistic strategy significantly improved modeling performance in most regions, with maximum increases in predictive power (as indicated by R2) of up to 18% compared with the baseline global transfer model. Remarkably, even when the number of global samples was reduced from 20,961 to around 200, the proposed strategy still outperformed local modeling and conventional global modeling approaches. In relatively stable environments, higher weights on environmental similarity yielded the best models, whereas in highly heterogeneous regions, spectral similarity played a more dominant role. The synergistic strategy also optimized the distribution of important spectral bands, enhanced SOC-responsive features in the visible region (450–750 nm), suppressed redundant information, and improved modeling efficiency. This study demonstrates that the proposed spectral-environmental synergistic sample transfer modeling method not only challenges the conventional assumption that “more samples guarantee better models” but also provides a novel pathway and theoretical support for the efficient use of global soil spectral libraries in regional SOC modeling.
{"title":"Selecting the right samples rather than more samples: A new spectral–environmental similarity strategy for local soil spectral modeling","authors":"Liangyi Li , Zipeng Zhang , Minglu Sun , Jianli Ding , Jingzhe Wang , Dong Xu , Yuanyuan Huang","doi":"10.1016/j.geoderma.2026.117710","DOIUrl":"10.1016/j.geoderma.2026.117710","url":null,"abstract":"<div><div>Addressing the dual challenges of limited sample size and high environmental heterogeneity in small-scale soil organic carbon (SOC) spectral modeling, this study proposes a fundamental hypothesis: selecting samples that are similar to the target region in both “spectral features and environmental characteristics” is more effective for improving prediction accuracy and stability. Based on this assumption, we developed a synergistic sample transfer strategy that integrates spectral similarity with environmental similarity under the Third Law of Geography, aiming to systematically screen the most comparable samples from the global soil spectral library to enhance the performance and robustness of local SOC modeling. A spectral-environmental similarity framework was established to identify samples that are simultaneously similar to the target region in spectral properties and environmental settings, and instance-based transfer modeling experiments were conducted in five representative small-sample regions (A-E). Results show that the synergistic strategy significantly improved modeling performance in most regions, with maximum increases in predictive power (as indicated by R<sup>2</sup>) of up to 18% compared with the baseline global transfer model. Remarkably, even when the number of global samples was reduced from 20,961 to around 200, the proposed strategy still outperformed local modeling and conventional global modeling approaches. In relatively stable environments, higher weights on environmental similarity yielded the best models, whereas in highly heterogeneous regions, spectral similarity played a more dominant role. The synergistic strategy also optimized the distribution of important spectral bands, enhanced SOC-responsive features in the visible region (450–750 nm), suppressed redundant information, and improved modeling efficiency. This study demonstrates that the proposed spectral-environmental synergistic sample transfer modeling method not only challenges the conventional assumption that “more samples guarantee better models” but also provides a novel pathway and theoretical support for the efficient use of global soil spectral libraries in regional SOC modeling.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"467 ","pages":"Article 117710"},"PeriodicalIF":6.6,"publicationDate":"2026-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146134155","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}
Pub Date : 2026-02-01DOI: 10.1016/j.geoderma.2026.117708
Xiaoai Cao , Huamin Liu , Rui Zhang , Yunhao Wen , Linqian Ma , Zhichao Xu , Lu Wen , Yi Zhuo , Dongwei Liu , Lixin Wang
Hummock wetlands are important ecosystem components for maintaining biogeochemical cycles and biodiversity. Currently, there remains a lack of systematic understanding of how hummock microtopography regulates soil multifunctionality (SMF). This study investigated 11 hummock wetlands in the Inner Mongolia Plateau. By comparing and analyzing the influence of hummocks (vs. hollows) on SMF and its nutrient cycling function, the synergistic regulatory mechanism of aboveground and underground biodiversity was revealed. The results showed that hummock significantly increased key single functional indicators such as SOC, URE, β-GC, aboveground biomass (AB), and underground biomass (UB) (P < 0.05), thereby significantly enhancing SMF. Especially in the functions of the carbon cycling, plant growth, and microbial activity (P < 0.05). Linear fitting analysis indicated that plant species richness was significantly positively correlated with SMF (P = 0.031), while microbial diversity, especially fungal diversity (Sob index, Shannon index, and ACE index), had a higher explanatory power for SMF (P < 0.05). The structural equation model showed that microtopography drives SMF by altering soil water content and, at the same time, by influencing soil pH and thereby affecting plant diversity. Furthermore, given the high explanatory power of fungal diversity for SMF, it was further identified that saprophytic fungi (such as Titaea, Dactylonectria, and Collarina) play key ecological functions in the process of organic matter decomposition and nutrient turnover. This study emphasizes the significance of protecting the heterogeneity of microtopography and the diversity of plants for the maintenance and restoration of wetland functions, providing a theoretical basis for the management of high-latitude wetlands.
{"title":"The interplay of aboveground and belowground biodiversity drives the soil multifunctionality of hummock wetlands","authors":"Xiaoai Cao , Huamin Liu , Rui Zhang , Yunhao Wen , Linqian Ma , Zhichao Xu , Lu Wen , Yi Zhuo , Dongwei Liu , Lixin Wang","doi":"10.1016/j.geoderma.2026.117708","DOIUrl":"10.1016/j.geoderma.2026.117708","url":null,"abstract":"<div><div>Hummock wetlands are important ecosystem components for maintaining biogeochemical cycles and biodiversity. Currently, there remains a lack of systematic understanding of how hummock microtopography regulates soil multifunctionality (SMF). This study investigated 11 hummock wetlands in the Inner Mongolia Plateau. By comparing and analyzing the influence of hummocks (vs. hollows) on SMF and its nutrient cycling function, the synergistic regulatory mechanism of aboveground and underground biodiversity was revealed. The results showed that hummock significantly increased key single functional indicators such as SOC, URE, β-GC, aboveground biomass (AB), and underground biomass (UB) (<em>P</em> < 0.05), thereby significantly enhancing SMF. Especially in the functions of the carbon cycling, plant growth, and microbial activity (<em>P</em> < 0.05). Linear fitting analysis indicated that plant species richness was significantly positively correlated with SMF (<em>P</em> = 0.031), while microbial diversity, especially fungal diversity (Sob index, Shannon index, and ACE index), had a higher explanatory power for SMF (<em>P</em> < 0.05). The structural equation model showed that microtopography drives SMF by altering soil water content and, at the same time, by influencing soil pH and thereby affecting plant diversity. Furthermore, given the high explanatory power of fungal diversity for SMF, it was further identified that saprophytic fungi (such as Titaea, Dactylonectria, and Collarina) play key ecological functions in the process of organic matter decomposition and nutrient turnover. This study emphasizes the significance of protecting the heterogeneity of microtopography and the diversity of plants for the maintenance and restoration of wetland functions, providing a theoretical basis for the management of high-latitude wetlands.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"466 ","pages":"Article 117708"},"PeriodicalIF":6.6,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146074599","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}
Pub Date : 2026-02-01DOI: 10.1016/j.geoderma.2026.117682
Chengcheng Jiang , Zhao Jin , Wen Fan , Ningyu Yu , Enlong Liu
Gully head erosion is considered a major form of soil degradation on the Loess Plateau, where distinctive topographic conditions promote runoff convergence during rainfall events and consequently intensify gully head retreat. However, systematic monitoring approaches and mitigation mechanisms under the combined effects of rainfall and inflow remain insufficiently understood. The objectives of this study are to reveal the synergistic mechanisms of rainfall and inflow driving gully head erosion through field experiments, and to establish hydrodynamic critical thresholds governing gully head erosion, thereby providing new insights for predicting erosion at the gully head by integrating topographic and hydraulic conditions. Through systematic field experiments, it was revealed that soil loss increased proportionally with both the rainfall intensity and the inflow rate. Moreover, catchment characteristics are the dominant factors influencing erosion dynamics at gully heads, with inflow playing a more significant role than rainfall in triggering gully wall expansion and collapse. Specifically, stream power is the optimal hydrodynamic parameter for predicting erosion rates, with a critical threshold of 2.33 N m−1 s−1 to distinguish stable and erosive conditions. Based on these findings, a dimensionless model was developed to predict gully head erosion under combined rainfall and inflow conditions, integrating both topographic and hydraulic parameters, and the model achieved high predictive accuracy (, ) for erosion initiation of gully head under complex rainfall-inflow interactions. This study establishes a simple and effective method for predicting erosion initiation and progression. These advances provide not only a mechanistic understanding of erosion drivers but also valuable scientific insights for rational engineering and management of the Loess Plateau.
沟头侵蚀被认为是黄土高原土壤退化的主要形式，其独特的地形条件促进了降雨期间径流的汇聚，从而加剧了沟头退缩。然而，对降雨和流入综合影响下的系统监测方法和缓解机制的了解仍然不够充分。本研究旨在通过野外试验揭示降雨和入流对沟头侵蚀的协同作用机制，建立控制沟头侵蚀的水动力临界阈值，从而为综合地形和水力条件预测沟头侵蚀提供新的见解。通过系统的田间试验，发现土壤流失量随降雨强度和入流速率成比例增加。流域特征是影响沟头侵蚀动力学的主导因素，在引发沟壁扩张和崩塌方面，入流比降雨的作用更为显著。具体来说，水流功率是预测侵蚀速率的最佳水动力参数，其临界阈值为2.33 N m−1 s−1，以区分稳定和侵蚀状态。在此基础上，建立了综合地形和水力参数的降雨-入流复合条件下沟头侵蚀无因次预测模型，该模型对复杂降雨-入流相互作用条件下沟头侵蚀起爆的预测精度较高（R2=0.843， NSE=0.788）。本研究建立了一种简单有效的预测侵蚀发生和发展的方法。这些研究成果不仅为黄土高原侵蚀机理的研究提供了理论依据，也为黄土高原的合理治理提供了科学依据。
{"title":"Experimental study of rainfall and inflow characteristics effects on gully head erosion on the Loess Plateau","authors":"Chengcheng Jiang , Zhao Jin , Wen Fan , Ningyu Yu , Enlong Liu","doi":"10.1016/j.geoderma.2026.117682","DOIUrl":"10.1016/j.geoderma.2026.117682","url":null,"abstract":"<div><div>Gully head erosion is considered a major form of soil degradation on the Loess Plateau, where distinctive topographic conditions promote runoff convergence during rainfall events and consequently intensify gully head retreat. However, systematic monitoring approaches and mitigation mechanisms under the combined effects of rainfall and inflow remain insufficiently understood. The objectives of this study are to reveal the synergistic mechanisms of rainfall and inflow driving gully head erosion through field experiments, and to establish hydrodynamic critical thresholds governing gully head erosion, thereby providing new insights for predicting erosion at the gully head by integrating topographic and hydraulic conditions. Through systematic field experiments, it was revealed that soil loss increased proportionally with both the rainfall intensity and the inflow rate. Moreover, catchment characteristics are the dominant factors influencing erosion dynamics at gully heads, with inflow playing a more significant role than rainfall in triggering gully wall expansion and collapse. Specifically, stream power is the optimal hydrodynamic parameter for predicting erosion rates, with a critical threshold of 2.33 N m<sup>−1</sup> s<sup>−1</sup> to distinguish stable and erosive conditions. Based on these findings, a dimensionless model was developed to predict gully head erosion under combined rainfall and inflow conditions, integrating both topographic and hydraulic parameters, and the model achieved high predictive accuracy (<span><math><mrow><msup><mrow><mi>R</mi></mrow><mn>2</mn></msup><mo>=</mo><mn>0.843</mn></mrow></math></span>, <span><math><mrow><msub><mi>N</mi><mrow><mi>SE</mi></mrow></msub><mo>=</mo><mn>0.788</mn></mrow></math></span>) for erosion initiation of gully head under complex rainfall-inflow interactions. This study establishes a simple and effective method for predicting erosion initiation and progression. These advances provide not only a mechanistic understanding of erosion drivers but also valuable scientific insights for rational engineering and management of the Loess Plateau.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"466 ","pages":"Article 117682"},"PeriodicalIF":6.6,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146001486","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}
Pub Date : 2026-02-01DOI: 10.1016/j.geoderma.2026.117709
Hao Su , Yuanyuan Yan , Qiqi He , Ya Li , Ruimin Li , Yi Ren , Xing Zhou , Liangliang Liu , Zucong Cai , Xinqi Huang
Intensive agricultural practices cause dysbiosis in soil nutrient levels and microbial communities, significantly affecting plant health and productivity. However, the mechanisms underlying the interactions between soil environmental factors and microbial communities, and their role in determining and predicting plant health, remain poorly understood. In this study, we collected soils planted with tomato in different health conditions, including healthy and bacterial wilt, Fusarium wilt, and nematode diseases, to identify key abiotic and biotic factors influencing plant health. Additionally, We fitted machine learning models using multidimensional data to classify plant health status. Our results revealed that diseased soils (bacterial wilt, Fusarium wilt, and nematode disease) exhibited significantly higher AP levels compared to healthy soils. Moreover, increased Amplicon Sequence Variants (ASVs) in diseased soils had lower network connectivity and were positively correlated with soil nutrient contents, pathogen abundance, and pathogen-supportive soil microbial functions, while being negatively correlated with plant defense-associated soil microbial functions. Both soil nutrient levels and the increased ASVs in diseased soil were stronger correlates of disease occurrence than other soil indicators. Optimal classification performance was observed when both soil environmental factors and microbial communities were considered, with AP emerging as the most influential indicator. In conclusion, excessive accumulation of AP was associated with disrupted microbial community structures, destabilized microbial networks, enhanced pathogen abundance, and impaired microbial functions, which collectively correlated with higher disease occurrence. These findings highlight the potential importance of optimizing soil nutrient management for supporting plant health.
{"title":"Interactions between soil environmental factors and microbial communities consistently predict plant health","authors":"Hao Su , Yuanyuan Yan , Qiqi He , Ya Li , Ruimin Li , Yi Ren , Xing Zhou , Liangliang Liu , Zucong Cai , Xinqi Huang","doi":"10.1016/j.geoderma.2026.117709","DOIUrl":"10.1016/j.geoderma.2026.117709","url":null,"abstract":"<div><div>Intensive agricultural practices cause dysbiosis in soil nutrient levels and microbial communities, significantly affecting plant health and productivity. However, the mechanisms underlying the interactions between soil environmental factors and microbial communities, and their role in determining and predicting plant health, remain poorly understood. In this study, we collected soils planted with tomato in different health conditions, including healthy and bacterial wilt, <em>Fusarium</em> wilt, and nematode diseases, to identify key abiotic and biotic factors influencing plant health. Additionally, We fitted machine learning models using multidimensional data to classify plant health status. Our results revealed that diseased soils (bacterial wilt, <em>Fusarium</em> wilt, and nematode disease) exhibited significantly higher AP levels compared to healthy soils. Moreover, increased Amplicon Sequence Variants (ASVs) in diseased soils had lower network connectivity and were positively correlated with soil nutrient contents, pathogen abundance, and pathogen-supportive soil microbial functions, while being negatively correlated with plant defense-associated soil microbial functions. Both soil nutrient levels and the increased ASVs in diseased soil were stronger correlates of disease occurrence than other soil indicators. Optimal classification performance was observed when both soil environmental factors and microbial communities were considered, with AP emerging as the most influential indicator. In conclusion, excessive accumulation of AP was associated with disrupted microbial community structures, destabilized microbial networks, enhanced pathogen abundance, and impaired microbial functions, which collectively correlated with higher disease occurrence. These findings highlight the potential importance of optimizing soil nutrient management for supporting plant health.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"466 ","pages":"Article 117709"},"PeriodicalIF":6.6,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146134164","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}
Pub Date : 2026-02-01DOI: 10.1016/j.geoderma.2026.117694
Anning Zhang , Ziyang Liu , Jingwei Chen , Hongxian Song , Jiajia Wang , Hanwen Cui , Zi Yang , Shuyan Chen , Lizhe An , Sa Xiao , Pedro Cardoso
Current climate change and anthropogenic activities are causing shrub encroachment, affecting biodiversity and ecosystem functioning. Shrub and their associated herbaceous plants and soil organisms will asynchronously colonize the new range, shaping different above and belowground relationships along climate gradients. With this work we quantify the functional linkage of plant and nematode communities in functional diversity and traits between shrubs and open spaces at 63 sites spanning broad climatic gradients on the Qinghai-Tibet Plateau. Shrub and climate interaction reshuffles herbaceous plant and nematode diversity and their function. Shrubs increased nematode taxonomic and functional diversity with increasing precipitation and temperature, but such shrub effects on plant diversity were independent of the climatic gradient. Shrub, precipitation, and temperature jointly modulate nematode traits, but have little effects on herbaceous plant traits. Shrubs increased nematodes with longer generation time, larger body mass, and at higher trophic levels, enhancing the metabolic footprint of soil communities; stronger modification on soil food webs and enrichment footprints amplified with increasing precipitation and temperature. Shifts in plant traits were associated with nematode C-P value and trophic structure, while Shrubs reduced the linkage between plants and nematodes in functional traits. Our study demonstrates that climate modulates the facilitative shrub effects on biodiversity and its functions, but points to the functional decoupling of plants and nematodes to environment shifts that may delay nutrient cycle and impact ecosystem functioning.
{"title":"Climate-dependent variations in plant and nematode functional traits following shrub encroachment","authors":"Anning Zhang , Ziyang Liu , Jingwei Chen , Hongxian Song , Jiajia Wang , Hanwen Cui , Zi Yang , Shuyan Chen , Lizhe An , Sa Xiao , Pedro Cardoso","doi":"10.1016/j.geoderma.2026.117694","DOIUrl":"10.1016/j.geoderma.2026.117694","url":null,"abstract":"<div><div>Current climate change and anthropogenic activities are causing shrub encroachment, affecting biodiversity and ecosystem functioning. Shrub and their associated herbaceous plants and soil organisms will asynchronously colonize the new range, shaping different above and belowground relationships along climate gradients. With this work we quantify the functional linkage of plant and nematode communities in functional diversity and traits between shrubs and open spaces at 63 sites spanning broad climatic gradients on the Qinghai-Tibet Plateau. Shrub and climate interaction reshuffles herbaceous plant and nematode diversity and their function. Shrubs increased nematode taxonomic and functional diversity with increasing precipitation and temperature, but such shrub effects on plant diversity were independent of the climatic gradient. Shrub, precipitation, and temperature jointly modulate nematode traits, but have little effects on herbaceous plant traits. Shrubs increased nematodes with longer generation time, larger body mass, and at higher trophic levels, enhancing the metabolic footprint of soil communities; stronger modification on soil food webs and enrichment footprints amplified with increasing precipitation and temperature. Shifts in plant traits were associated with nematode C-P value and trophic structure, while Shrubs reduced the linkage between plants and nematodes in functional traits. Our study demonstrates that climate modulates the facilitative shrub effects on biodiversity and its functions, but points to the functional decoupling of plants and nematodes to environment shifts that may delay nutrient cycle and impact ecosystem functioning.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"466 ","pages":"Article 117694"},"PeriodicalIF":6.6,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146033235","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}
Pub Date : 2026-02-01DOI: 10.1016/j.geoderma.2026.117689
Antonia Zieger , Klaus Kaiser , Martin Kaupenjohann
<div><div>Andosols are commonly subdivided according to silandic and aluandic features. Silandic Andosols are characterised by organic matter (OM) strongly bound to short-range ordered aluminosilicates (SROAS), while aluandic Andosols mainly consist of aluminium-OM complexes (Al-OM complexes). Two theories exist concerning their pedogenesis. One theory argues, that silandic and aluandic properties are direct results of the weathering, assuming two separate lines of genesis. The other theory argues that silandic horizons transform into aluandic over time as parts of a continuous soil forming process. The latter could be caused by dissolved organic matter (DOM) entering the silandic subsoil with the percolating soil solution and promoting the dissolution of SROAS phases by complexing Al. Increasing the loading of DOM with Al will finally result in the formation of insoluble Al-OM complexes.</div><div>To test the hypothesis of in-situ transition from silandic to aluandic properties in a controlled experiment, we conducted a 20-month percolation experiment with soil material of an Ecuadorian Andosol formed in a homogeneous tephra deposit and now featuring aluandic properties in the top- and silandic properties in the subsoil. Six columns were packed with aluandic material on top of silandic material, water saturated and percolated with litter DOM-solution continuously (percolation rate 8<!--> <!-->mm<span><math><mi>⋅</mi></math></span>h<sup>−1</sup>, except for a 9-week flow stop at the beginning of the experiment). In addition, three columns were packed only with aluandic material to gain additional information on the solution entering the silandic material. Among others, silicon (Si) and Al, pH, and dissolved organic carbon (DOC) in the feed and eluate solutions were monitored over a period of 20 months. We modelled the percolation experiment with the convection–dispersion equation as implemented in HYDRUS-1D to estimate the amount of retained DOC in the silandic material. Changes in OC concentration and mineral phases were tracked by analysing the column materials after 0, 8, and 20 months for OC concentrations, oxalate-extractable Al, Si, and iron (Fe) concentrations, and by X-ray diffraction.</div><div>Our results show that percolation had little to no effect on the aluandic material. However, for the silandic eluate the molar Al:Si ratio was well below the oxalate-extractable Alox:Siox molar ratio of the silandic material itself. This hints at desilification, while Al and OC are retained relative to Si and hence supporting the hypothesis of SROAS dissolution and neo-formation of Al-OM complexes. The latter explained up to 70<!--> <!-->% of the massive OC accumulation of 14<!--> <!-->mg<span><math><mi>⋅</mi></math></span>g<sup>−1</sup> in the silandic material, while vertical Al-OM transport and sorption played a minor role. This was supported by the HYDRUS-1D modelling, suggesting that sorption of DOM to the silandic material only dominates in
{"title":"Dissolved organic matter and high precipitation drive in-situ transition from silandic to aluandic properties","authors":"Antonia Zieger , Klaus Kaiser , Martin Kaupenjohann","doi":"10.1016/j.geoderma.2026.117689","DOIUrl":"10.1016/j.geoderma.2026.117689","url":null,"abstract":"<div><div>Andosols are commonly subdivided according to silandic and aluandic features. Silandic Andosols are characterised by organic matter (OM) strongly bound to short-range ordered aluminosilicates (SROAS), while aluandic Andosols mainly consist of aluminium-OM complexes (Al-OM complexes). Two theories exist concerning their pedogenesis. One theory argues, that silandic and aluandic properties are direct results of the weathering, assuming two separate lines of genesis. The other theory argues that silandic horizons transform into aluandic over time as parts of a continuous soil forming process. The latter could be caused by dissolved organic matter (DOM) entering the silandic subsoil with the percolating soil solution and promoting the dissolution of SROAS phases by complexing Al. Increasing the loading of DOM with Al will finally result in the formation of insoluble Al-OM complexes.</div><div>To test the hypothesis of in-situ transition from silandic to aluandic properties in a controlled experiment, we conducted a 20-month percolation experiment with soil material of an Ecuadorian Andosol formed in a homogeneous tephra deposit and now featuring aluandic properties in the top- and silandic properties in the subsoil. Six columns were packed with aluandic material on top of silandic material, water saturated and percolated with litter DOM-solution continuously (percolation rate 8<!--> <!-->mm<span><math><mi>⋅</mi></math></span>h<sup>−1</sup>, except for a 9-week flow stop at the beginning of the experiment). In addition, three columns were packed only with aluandic material to gain additional information on the solution entering the silandic material. Among others, silicon (Si) and Al, pH, and dissolved organic carbon (DOC) in the feed and eluate solutions were monitored over a period of 20 months. We modelled the percolation experiment with the convection–dispersion equation as implemented in HYDRUS-1D to estimate the amount of retained DOC in the silandic material. Changes in OC concentration and mineral phases were tracked by analysing the column materials after 0, 8, and 20 months for OC concentrations, oxalate-extractable Al, Si, and iron (Fe) concentrations, and by X-ray diffraction.</div><div>Our results show that percolation had little to no effect on the aluandic material. However, for the silandic eluate the molar Al:Si ratio was well below the oxalate-extractable Alox:Siox molar ratio of the silandic material itself. This hints at desilification, while Al and OC are retained relative to Si and hence supporting the hypothesis of SROAS dissolution and neo-formation of Al-OM complexes. The latter explained up to 70<!--> <!-->% of the massive OC accumulation of 14<!--> <!-->mg<span><math><mi>⋅</mi></math></span>g<sup>−1</sup> in the silandic material, while vertical Al-OM transport and sorption played a minor role. This was supported by the HYDRUS-1D modelling, suggesting that sorption of DOM to the silandic material only dominates in ","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"466 ","pages":"Article 117689"},"PeriodicalIF":6.6,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146072101","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}
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