Pub Date : 2026-01-16DOI: 10.1016/j.geoderma.2026.117679
Wei Peng , Meng Zhang , Yili Lu , Zhengchao Tian , Yajing Wang , Tusheng Ren
Traditional heat-pulse methods for determining soil thermal properties require frequent probe spacing calibrations due to their susceptibility to geometric errors in heat capacity (C) estimation. Here we present a novel calibration-free thermo-TDR technique as a methodological innovation that concurrently measures soil bulk density (ρb), thermal conductivity (λ), and C by integrating heat-pulse theory with soil constitutive relationships within a unified inversion framework. The procedure: (i) directly calculates λ from heat-pulse signals using physical probe spacing without calibration; (ii) predicts ρb via a λ-ρb model that is parameterized with soil texture and TDR-derived water content (θTDR); and (iii) estimates C from ρb and θTDR using the de Vries (1963) model. This approach eliminates the need for probe spacing calibration, which is a key limitation of traditional methods. Laboratory validation with packed soils yielded high accuracy (RMSE: ≤0.08 Mg m−3 for ρb; ≤0.11 MJ m−3 K−1 for C). Field deployments tracked dynamic ρb and C during natural drying events (mean RMSE: 0.09 Mg m−3 for ρb, 0.13 MJ m−3 K−1 for C), outperforming traditional spaced probe methods that were sensitive to sensor misalignment. Eliminating probe spacing calibration makes this approach ideal for long-term monitoring and integration with automated field sensor networks, advancing studies of soil–water-energy dynamics in agronomic and vadose zone hydrology.
{"title":"A calibration-free approach for measuring soil thermal properties and bulk density using the thermo-TDR technique","authors":"Wei Peng , Meng Zhang , Yili Lu , Zhengchao Tian , Yajing Wang , Tusheng Ren","doi":"10.1016/j.geoderma.2026.117679","DOIUrl":"10.1016/j.geoderma.2026.117679","url":null,"abstract":"<div><div>Traditional heat-pulse methods for determining soil thermal properties require frequent probe spacing calibrations due to their susceptibility to geometric errors in heat capacity (<em>C</em>) estimation. Here we present a novel calibration-free thermo-TDR technique as a methodological innovation that concurrently measures soil bulk density (<em>ρ</em><sub>b</sub>), thermal conductivity (<em>λ</em>), and <em>C</em> by integrating heat-pulse theory with soil constitutive relationships within a unified inversion framework. The procedure: (i) directly calculates <em>λ</em> from heat-pulse signals using physical probe spacing without calibration; (ii) predicts <em>ρ</em><sub>b</sub> via a <em>λ</em>-<em>ρ</em><sub>b</sub> model that is parameterized with soil texture and TDR-derived water content (<em>θ</em><sub>TDR</sub>); and (iii) estimates <em>C</em> from <em>ρ</em><sub>b</sub> and <em>θ</em><sub>TDR</sub> using the <span><span>de Vries (1963)</span></span> model. This approach eliminates the need for probe spacing calibration, which is a key limitation of traditional methods. Laboratory validation with packed soils yielded high accuracy (<em>RMSE</em>: ≤0.08 Mg m<sup>−3</sup> for <em>ρ</em><sub>b</sub>; ≤0.11 MJ m<sup>−3</sup> K<sup>−1</sup> for <em>C</em>). Field deployments tracked dynamic <em>ρ</em><sub>b</sub> and <em>C</em> during natural drying events (mean <em>RMSE</em>: 0.09 Mg m<sup>−3</sup> for <em>ρ</em><sub>b</sub>, 0.13 MJ m<sup>−3</sup> K<sup>−1</sup> for <em>C</em>), outperforming traditional spaced probe methods that were sensitive to sensor misalignment. Eliminating probe spacing calibration makes this approach ideal for long-term monitoring and integration with automated field sensor networks, advancing studies of soil–water-energy dynamics in agronomic and vadose zone hydrology.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"466 ","pages":"Article 117679"},"PeriodicalIF":6.6,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145975324","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 : 2026-01-16DOI: 10.1016/j.geoderma.2026.117683
Jan-František Kubát, Michal Vrána, Adam Babuljak, David Zumr
Soils exhibit considerable variability in their physical and hydraulic properties, which can change both spatially and temporally. However, studies capturing short-term temporal and internal vertical variability within tilled topsoil remain limited. In this one-year study (May 2023–2024), we investigated seasonal changes in the physical and hydraulic properties of the bare topsoil after tillage in a humid continental climate in Czechia. Monthly sampling was conducted on a 16 m2 plot, targeting the upper 12 cm of soil, divided into 0 to 5 cm and 7 to 12 cm layers. A total of 28 disturbed and 107 undisturbed samples were collected, and 40 soil water retention curves (SWRCs) were measured and fitted with the van Genuchten–Mualem model to derive hydraulic parameters (α, n, θr, θs, Ks). Robust statistical analyses (permutation tests, Kruskal–Wallis, Dunn’s test, LOWESS, and MANOVA) were used to evaluate vertical and temporal variability. The results revealed significant changes in the hydraulic properties of the fitted devices. The depth explained approximately half of the total multivariate variance (η2 ≈ 0.5), while time accounted for roughly one-third (η2 ≈ 0.3–0.4). The upper layer exhibited greater heterogeneity in the n parameter (1.404 ± 0.126) compared to the deeper layer (1.254 ± 0.103), while α showed comparable variability (0.060 ± 0.019 vs. 0.075 ± 0.024). These moderate-to-large effect sizes indicate that, even within the first 12 cm, hydraulic behavior is neither uniform nor static. The contrasting patterns between the fitted full SWRCs and their derived parameters highlight the importance of evaluating both datasets jointly. Relying solely on parameter statistics or individual retention curve risks overlooking meaningful temporal and vertical dynamics. Our findings demonstrate that post-tillage topsoil evolves structurally and hydraulically even in the absence of vegetation or management, emphasizing the need for depth- and time-resolved parameterization in hydrological and soil-process modeling.
土壤的物理和水力特性表现出相当大的变异性，可以在空间和时间上发生变化。然而，在耕作表土中捕捉短期时间和内部垂直变化的研究仍然有限。在这项为期一年（2023-2024年5月）的研究中，我们研究了捷克湿润大陆性气候下裸露表土耕作后物理和水力特性的季节变化。每月取样面积为16 m2，取样范围为土壤上部12 cm，分为0 ~ 5 cm层和7 ~ 12 cm层。共采集28个扰动样和107个未扰动样，测量40条土壤保水曲线（SWRCs），采用van Genuchten-Mualem模型拟合得到水力参数（α, n, θr, θs, Ks）。采用稳健的统计分析（排列检验、Kruskal-Wallis检验、Dunn检验、LOWESS和方差分析）来评估垂直和时间变异。结果显示，安装装置的水力性能发生了显著变化。深度解释了大约一半的多变量方差（η2≈0.5），而时间解释了大约三分之一（η2≈0.3-0.4）。上层n参数的异质性（1.404±0.126）大于下层（1.254±0.103），而α参数的异质性（0.060±0.019 vs. 0.075±0.024）具有可比性。这些中等到较大的效应表明，即使在最初的12厘米内，水力行为既不是均匀的，也不是静态的。拟合的完整swrc及其衍生参数之间的对比模式突出了联合评估两个数据集的重要性。仅仅依赖于参数统计数据或个人留存曲线可能会忽视有意义的时间和垂直动态。我们的研究结果表明，即使在没有植被或管理的情况下，耕作后的表土在结构和水力上也会发生变化，这强调了在水文和土壤过程建模中需要深度和时间分辨参数化。
{"title":"Temporal and Vertical Variability of Post-Tillage Topsoil Hydraulic Properties at a Local Scale","authors":"Jan-František Kubát, Michal Vrána, Adam Babuljak, David Zumr","doi":"10.1016/j.geoderma.2026.117683","DOIUrl":"10.1016/j.geoderma.2026.117683","url":null,"abstract":"<div><div>Soils exhibit considerable variability in their physical and hydraulic properties, which can change both spatially and temporally. However, studies capturing short-term temporal and internal vertical variability within tilled topsoil remain limited. In this one-year study (May 2023–2024), we investigated seasonal changes in the physical and hydraulic properties of the bare topsoil after tillage in a humid continental climate in Czechia. Monthly sampling was conducted on a 16 m<sup>2</sup> plot, targeting the upper 12 cm of soil, divided into 0 to 5 cm and 7 to 12 cm layers. A total of 28 disturbed and 107 undisturbed samples were collected, and 40 soil water retention curves (SWRCs) were measured and fitted with the van Genuchten–Mualem model to derive hydraulic parameters (<em>α, n, θ<sub>r</sub>, θ<sub>s</sub>, K<sub>s</sub></em>). Robust statistical analyses (permutation tests, Kruskal–Wallis, Dunn’s test, LOWESS, and MANOVA) were used to evaluate vertical and temporal variability. The results revealed significant changes in the hydraulic properties of the fitted devices. The depth explained approximately half of the total multivariate variance (η<sup>2</sup> ≈ 0.5), while time accounted for roughly one-third (η<sup>2</sup> ≈ 0.3–0.4). The upper layer exhibited greater heterogeneity in the <em>n</em> parameter (1.404 ± 0.126) compared to the deeper layer (1.254 ± 0.103), while <em>α</em> showed comparable variability (0.060 ± 0.019 vs. 0.075 ± 0.024). These moderate-to-large effect sizes indicate that, even within the first 12 cm, hydraulic behavior is neither uniform nor static. The contrasting patterns between the fitted full SWRCs and their derived parameters highlight the importance of evaluating both datasets jointly. Relying solely on parameter statistics or individual retention curve risks overlooking meaningful temporal and vertical dynamics. Our findings demonstrate that post-tillage topsoil evolves structurally and hydraulically even in the absence of vegetation or management, emphasizing the need for depth- and time-resolved parameterization in hydrological and soil-process modeling.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"466 ","pages":"Article 117683"},"PeriodicalIF":6.6,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145975323","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 : 2026-01-16DOI: 10.1016/j.geoderma.2026.117687
Wojciech Piaszczyk , Andrzej Szlachta , Stanisław Łyszczarz , Norbert Szymański , Michał Jasik , Mirosław Żelazny , Stanisław Małek , Jarosław Lasota , Ewa Błońska
Although peatlands cover only a small fraction of the Earth’s surface, they store large amounts of carbon and play a key role in global biogeochemical cycles. A joint assessment of the stoichiometry of biogenic elements (C, N and P) and nutrients ratios may improve our understanding of soil–plant interactions across different types of Histosol. The aim of this study was to analyse the stoichiometry of C:N:P and nutrients ratios in peat soils and conifer needles (Picea abies and Pinus sylvestris) across three different histosol types: fibric, hemic and sapric. Particular emphasis was placed on soil–plant relationships and evaluating the potential of stoichiometric indicators to diagnose peatland condition. Samples were collected from 255 sites across Poland. Composite soil samples (0–15 cm depth) and conifer needles were analysed for C and N using an elemental analyser, and for Ca, Mg, K, Al and P using ICP-OES. Ratios (C/N, C/P, N/P, Ca/Mg, Ca/Al and Ca·K·Mg/Al) were then calculated. Statistical procedures included descriptive statistics (median and quartile deviation), a Kruskal–Wallis test (p < 0.05), a principal component analysis (PCA), generalised linear models (GLM), Spearman’s rank correlations and simple linear regressions. Soil carbon content, as well as the C/N, C/P and N/P ratios, decreased systematically from fibric to sapric histosols. Meanwhile, the contents of Ca, Mg, K and Al were significantly higher in sapric soils. In plants, the contents of C, N and P, as well as the C/N, C/P and N/P ratios, did not differ between histosol types. However, the ratios (particularly Ca/Al and Ca·K·Mg/Al) were highest in sapric histosols. Soil–plant correlations were weak for C/N, C/P, and N/P, but slightly stronger for Ca/Al and Ca·K·Mg/Al. PCA (PC1 = 35.52 %; PC2 = 19.41 %) revealed a clear separation, with plants associated with phosphorus and nutrients ratios and soils grouped with C/N and C/P. GLM confirmed the significant effects of both sample and histosol types, with an interaction observed for most indices (except Ca/Mg). Both classical ratios (C/N, C/P and N/P) and ratios (Ca/Al, Ca/Mg and Ca·K·Mg/Al) provide complementary insights into peatland functioning. The decline of C/N and C/P ratios with increasing humification, combined with higher nutrient ratios, indicates their potential for diagnosing peatland degradation and monitoring nutrient cycling dynamics.
{"title":"Stoichiometry of peatlands and plants: Mutual interactions in biogeochemical cycles","authors":"Wojciech Piaszczyk , Andrzej Szlachta , Stanisław Łyszczarz , Norbert Szymański , Michał Jasik , Mirosław Żelazny , Stanisław Małek , Jarosław Lasota , Ewa Błońska","doi":"10.1016/j.geoderma.2026.117687","DOIUrl":"10.1016/j.geoderma.2026.117687","url":null,"abstract":"<div><div>Although peatlands cover only a small fraction of the Earth’s surface, they store large amounts of carbon and play a key role in global biogeochemical cycles. A joint assessment of the stoichiometry of biogenic elements (C, N and P) and nutrients ratios may improve our understanding of soil–plant interactions across different types of Histosol. The aim of this study was to analyse the stoichiometry of C:N:P and nutrients ratios in peat soils and conifer needles (<em>Picea abies</em> and <em>Pinus sylvestris</em>) across three different histosol types: fibric, hemic and sapric. Particular emphasis was placed on soil–plant relationships and evaluating the potential of stoichiometric indicators to diagnose peatland condition. Samples were collected from 255 sites across Poland. Composite soil samples (0–15 cm depth) and conifer needles were analysed for C and N using an elemental analyser, and for Ca, Mg, K, Al and P using ICP-OES. Ratios (C/N, C/P, N/P, Ca/Mg, Ca/Al and Ca·K·Mg/Al) were then calculated. Statistical procedures included descriptive statistics (median and quartile deviation), a Kruskal–Wallis test (p < 0.05), a principal component analysis (PCA), generalised linear models (GLM), Spearman’s rank correlations and simple linear regressions. Soil carbon content, as well as the C/N, C/P and N/P ratios, decreased systematically from fibric to sapric histosols. Meanwhile, the contents of Ca, Mg, K and Al were significantly higher in sapric soils. In plants, the contents of C, N and P, as well as the C/N, C/P and N/P ratios, did not differ between histosol types. However, the ratios (particularly Ca/Al and Ca·K·Mg/Al) were highest in sapric histosols. Soil–plant correlations were weak for C/N, C/P, and N/P, but slightly stronger for Ca/Al and Ca·K·Mg/Al. PCA (PC1 = 35.52 %; PC2 = 19.41 %) revealed a clear separation, with plants associated with phosphorus and nutrients ratios and soils grouped with C/N and C/P. GLM confirmed the significant effects of both sample and histosol types, with an interaction observed for most indices (except Ca/Mg). Both classical ratios (C/N, C/P and N/P) and ratios (Ca/Al, Ca/Mg and Ca·K·Mg/Al) provide complementary insights into peatland functioning. The decline of C/N and C/P ratios with increasing humification, combined with higher nutrient ratios, indicates their potential for diagnosing peatland degradation and monitoring nutrient cycling dynamics.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"466 ","pages":"Article 117687"},"PeriodicalIF":6.6,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145975322","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 : 2026-01-15DOI: 10.1016/j.geoderma.2025.117667
D. Álvarez , E. Playà , O. Artieda , R. Rodríguez-Ochoa , J.R. Olarieta , R.M. Poch
The loess palaeosol sequences in the Ebro valley are associated with arid and semi-arid climates in the past, where the main pedogenic process is the mobilisation of carbonate and gypsum through the soil, resulting in secondary accumulations. Due to the fact that, in this context, the conservation of palaeoenvironmental indicators is very limited, the objective of this research is to explore the potential of pedogenic gypsum to provide with information about the palaeoenvironmental conditions affecting its development and preservation.
This study has consisted in the sampling and analysis of pedogenic gypsum accumulations from five Loess-Palaeosol Sequences (LPS) applying several approaches and analytical techniques. Traditional methods based on the morphological study of gypsum and supported by micromorphological research have been applied, allowing us the observation of crystalline shapes, pedofeatures and mineral arrangements. We also performed isotopic analyses of pedogenic gypsum, including the isotopic signature of the stable sulphate (δ34S, δ18O) and gypsum hydration water (δ2H, δ18O). Besides, the minor and trace elements composition (Ba, Sr, Na, K, and Mg) was also analysed.
Despite the difficulties when analysing pedogenic gypsum, due in part to its high solubility, our results show that the intensity of the dissolution/reprecipitation processes combined with the loess sedimentation rates determine gypsum characteristics and distribution in the studied loess profiles. Besides helping to determine the gypsum primary source areas, isotopic and micromorphological analyses suggest possible regional and temporal paleoclimatic differences (more/less arid) from the close or more open systems of gypsum in relation to meteoric water.
In addition, the minor and trace elements composition suggests the presence of fluid and solid inclusions in the gypsum crystals of some horizons. This corresponds to gypsum formation in a medium with water rich in sulphates and other salts, and an increased proportion of primary gypsum in the sediment, in contrast to the precipitation of gypsum in unsaturated water.
The combination of different methods has confirmed that pedogenic gypsum is a potential tool for improving palaeoenvironmental knowledge in arid and semi-arid regions. However, due to its limitations, it is recommended to combine additional techniques and indicators to use pedogenic gypsum as an effective palaeoenvironmental proxy.
{"title":"Isotopy, micromorphology and composition of pedogenic gypsum in loess-palaeosol sequences in the Ebro Valley as a combined paleoenvironmental proxy","authors":"D. Álvarez , E. Playà , O. Artieda , R. Rodríguez-Ochoa , J.R. Olarieta , R.M. Poch","doi":"10.1016/j.geoderma.2025.117667","DOIUrl":"10.1016/j.geoderma.2025.117667","url":null,"abstract":"<div><div>The loess palaeosol sequences in the Ebro valley are associated with arid and semi-arid climates in the past, where the main pedogenic process is the mobilisation of carbonate and gypsum through the soil, resulting in secondary accumulations. Due to the fact that, in this context, the conservation of palaeoenvironmental indicators is very limited, the objective of this research is to explore the potential of pedogenic gypsum to provide with information about the palaeoenvironmental conditions affecting its development and preservation.</div><div>This study has consisted in the sampling and analysis of pedogenic gypsum accumulations from five Loess-Palaeosol Sequences (LPS) applying several approaches and analytical techniques. Traditional methods based on the morphological study of gypsum and supported by micromorphological research have been applied, allowing us the observation of crystalline shapes, pedofeatures and mineral arrangements. We also performed isotopic analyses of pedogenic gypsum, including the isotopic signature of the stable sulphate (δ<sup>34</sup>S, δ<sup>18</sup>O) and gypsum hydration water (δ<sup>2</sup>H, δ<sup>18</sup>O). Besides, the minor and trace elements composition (Ba, Sr, Na, K, and Mg) was also analysed.</div><div>Despite the difficulties when analysing pedogenic gypsum, due in part to its high solubility, our results show that the intensity of the dissolution/reprecipitation processes combined with the loess sedimentation rates determine gypsum characteristics and distribution in the studied loess profiles. Besides helping to determine the gypsum primary source areas, isotopic and micromorphological analyses suggest possible regional and temporal paleoclimatic differences (more/less arid) from the close or more open systems of gypsum in relation to meteoric water.</div><div>In addition, the minor and trace elements composition suggests the presence of fluid and solid inclusions in the gypsum crystals of some horizons. This corresponds to gypsum formation in a medium with water rich in sulphates and other salts, and an increased proportion of primary gypsum in the sediment, in contrast to the precipitation of gypsum in unsaturated water.</div><div>The combination of different methods has confirmed that pedogenic gypsum is a potential tool for improving palaeoenvironmental knowledge in arid and semi-arid regions. However, due to its limitations, it is recommended to combine additional techniques and indicators to use pedogenic gypsum as an effective palaeoenvironmental proxy.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"466 ","pages":"Article 117667"},"PeriodicalIF":6.6,"publicationDate":"2026-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974844","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}
Perennial cropping systems hold great potential to enhance soil organic carbon (SOC) stocks and contribute to climate change mitigation. However, the effects of perennial crops on SOC fractions with different stabilities remain poorly understood. Particulate organic carbon (POC) and mineral-associated organic carbon (MAOC) are considered to have different formation mechanisms and different stabilities. Plant- and microbial-derived carbon (C) are the main origins of SOC, yet their relative contributions to POC and MAOC remain unclear. Here, based on an 11-year experiment, we compared two perennial cropping systems (festulolium and grass-clover) with an annual cropping system (maize), to investigate their effects on soil POC and MAOC, and quantify the contribution of plant- and microbial-derived C to these two soil C fractions using lignin phenols and amino sugars as biomarkers.
The soil of the two perennials had higher POC and MAOC than maize at 0–20 cm soil depth, with higher proportions of POC in SOC. The higher POC of the two perennials was linked to their significantly higher fungal and bacterial necromass C in POC. Total microbial necromass C accounted for only 29% of POC and 36% of MAOC at 0–20 cm across all systems, suggesting that plant-derived C dominates these two C pools. However, no significant differences were detected in the lignin phenols content in POC and MAOC at 0–20 cm. Our results challenge the conventional assumption that microbial necromass C dominates MAOC, highlighting the role of plant-derived C in POC and MAOC, which could have a greater influence on soil C sequestration in climates with low mean annual temperature than previously assumed. Given that only two biomarkers were used, interpretations should not be extrapolated beyond their analytical scope.
{"title":"Microbial and plant-derived carbon contributions to particulate and mineral-associated organic carbon in perennial and annual cropping systems","authors":"Yiwei Shang , Zhi Liang , Imran Ahammad Siddique , Michaela Dippold , Diego Abalos , Jørgen Eivind Olesen","doi":"10.1016/j.geoderma.2026.117688","DOIUrl":"10.1016/j.geoderma.2026.117688","url":null,"abstract":"<div><div>Perennial cropping systems hold great potential to enhance soil organic carbon (SOC) stocks and contribute to climate change mitigation. However, the effects of perennial crops on SOC fractions with different stabilities remain poorly understood. Particulate organic carbon (POC) and mineral-associated organic carbon (MAOC) are considered to have different formation mechanisms and different stabilities. Plant- and microbial-derived carbon (C) are the main origins of SOC, yet their relative contributions to POC and MAOC remain unclear. Here, based on an 11-year experiment, we compared two perennial cropping systems (festulolium and grass-clover) with an annual cropping system (maize), to investigate their effects on soil POC and MAOC, and quantify the contribution of plant- and microbial-derived C to these two soil C fractions using lignin phenols and amino sugars as biomarkers.</div><div>The soil of the two perennials had higher POC and MAOC than maize at 0–20 cm soil depth, with higher proportions of POC in SOC. The higher POC of the two perennials was linked to their significantly higher fungal and bacterial necromass C in POC. Total microbial necromass C accounted for only 29% of POC and 36% of MAOC at 0–20 cm across all systems, suggesting that plant-derived C dominates these two C pools. However, no significant differences were detected in the lignin phenols content in POC and MAOC at 0–20 cm. Our results challenge the conventional assumption that microbial necromass C dominates MAOC, highlighting the role of plant-derived C in POC and MAOC, which could have a greater influence on soil C sequestration in climates with low mean annual temperature than previously assumed. Given that only two biomarkers were used, interpretations should not be extrapolated beyond their analytical scope.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"466 ","pages":"Article 117688"},"PeriodicalIF":6.6,"publicationDate":"2026-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974843","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 : 2026-01-14DOI: 10.1016/j.geoderma.2026.117681
Tianli Lan , Yuanming Lai , Xiaoxiao Luo , Fan Yu , Qinguo Ma
Permafrost degradation on the Tibetan Plateau (TP) poses serious risks to the environment and infrastructure. Permafrost changes are controlled by both climate changes and local factors, including climate warming, wetting, and aeolian desertification, but the heat transfer process and hydrothermal mechanism under aeolian sand cover (ASC) remain poorly understood. Using a model test and a coupling numerical model, this study analyzes the effects and mechanisms of warming and wetting on permafrost under ASC. The results indicate that: Under thin ASC, infiltration is tiny and heat conduction dominates heat transfer, and climate warming increases surface heat flux and accelerates permafrost degradation by enhancing the net radiation and reducing the sensible heat. Under thick ASC, infiltration and heat convection become significant, and climate warming increases the annual infiltration by extending the thawing period, drives the decrease in latent heat of evaporation, and further promotes permafrost degradation. As precipitation increases, thin ASC cools the permafrost by enhancing evaporation and reducing surface heat flux. In contrast, thick ASC warms the permafrost by suppressing evaporation increment and enhancing both surface heat flux and subsurface heat convection.
{"title":"Multiple thermophysical effects of aeolian sand cover on permafrost under climate warming and wetting","authors":"Tianli Lan , Yuanming Lai , Xiaoxiao Luo , Fan Yu , Qinguo Ma","doi":"10.1016/j.geoderma.2026.117681","DOIUrl":"10.1016/j.geoderma.2026.117681","url":null,"abstract":"<div><div>Permafrost degradation on the Tibetan Plateau (TP) poses serious risks to the environment and infrastructure. Permafrost changes are controlled by both climate changes and local factors, including climate warming, wetting, and aeolian desertification, but the heat transfer process and hydrothermal mechanism under aeolian sand cover (ASC) remain poorly understood. Using a model test and a coupling numerical model, this study analyzes the effects and mechanisms of warming and wetting on permafrost under ASC. The results indicate that: Under thin ASC, infiltration is tiny and heat conduction dominates heat transfer, and climate warming increases surface heat flux and accelerates permafrost degradation by enhancing the net radiation and reducing the sensible heat. Under thick ASC, infiltration and heat convection become significant, and climate warming increases the annual infiltration by extending the thawing period, drives the decrease in latent heat of evaporation, and further promotes permafrost degradation. As precipitation increases, thin ASC cools the permafrost by enhancing evaporation and reducing surface heat flux. In contrast, thick ASC warms the permafrost by suppressing evaporation increment and enhancing both surface heat flux and subsurface heat convection.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"466 ","pages":"Article 117681"},"PeriodicalIF":6.6,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145962588","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 : 2026-01-14DOI: 10.1016/j.geoderma.2026.117674
William Osterholz , Kevin King , Margaret Kalcic , Vinayak Shedekar
Soil health is an objective of management practices including reduced tillage intensity, manure application, crop rotation, and cover crops. However, the relative effectiveness of these practices for promoting healthier soil remains uncertain. We assessed the responses of six soil health indicators (soil organic matter, soil respiration, permanganate oxidizable C (POX-C), soil protein, mean weight diameter of water stable aggregates, and bulk density) to four management practices (manure application, reduced tillage, living cover in fall and spring, and crop diversity) across 50 commercial crop fields in Ohio and Indiana, USA. Simple linear regression, multiple linear regression and random forest analyses largely identified similar relationships between soil health and management practices. Manure application rate was consistently and positively associated with greater soil health values, although the relationship with bulk density was weak. Reduced tillage intensity was associated with greater protein and respiration, but decreased POX-C. Living cover and crop diversity each had limited relationships with the soil health indicators. Soil texture was an important factor driving variability in most soil health indicators. Reducing the management period from 5 yr to 3 yr tended to reduce the predictive ability of the models, but with limited exceptions similar relationships between management and soil health were identifiable. The depth of measurement of soil health indicators changed the interpretation of management-soil health relationships in only one instance (POX-C vs. reduced tillage intensity). Overall, manure application was the most effective practice for improving soil health, with reduced tillage intensity also effective for improving several soil health indicators.
{"title":"Soil health indicators respond to management practices on commercial farms","authors":"William Osterholz , Kevin King , Margaret Kalcic , Vinayak Shedekar","doi":"10.1016/j.geoderma.2026.117674","DOIUrl":"10.1016/j.geoderma.2026.117674","url":null,"abstract":"<div><div>Soil health is an objective of management practices including reduced tillage intensity, manure application, crop rotation, and cover crops. However, the relative effectiveness of these practices for promoting healthier soil remains uncertain. We assessed the responses of six soil health indicators (soil organic matter, soil respiration, permanganate oxidizable C (POX-C), soil protein, mean weight diameter of water stable aggregates, and bulk density) to four management practices (manure application, reduced tillage, living cover in fall and spring, and crop diversity) across 50 commercial crop fields in Ohio and Indiana, USA. Simple linear regression, multiple linear regression and random forest analyses largely identified similar relationships between soil health and management practices. Manure application rate was consistently and positively associated with greater soil health values, although the relationship with bulk density was weak. Reduced tillage intensity was associated with greater protein and respiration, but decreased POX-C. Living cover and crop diversity each had limited relationships with the soil health indicators. Soil texture was an important factor driving variability in most soil health indicators. Reducing the management period from 5 yr to 3 yr tended to reduce the predictive ability of the models, but with limited exceptions similar relationships between management and soil health were identifiable. The depth of measurement of soil health indicators changed the interpretation of management-soil health relationships in only one instance (POX-C vs. reduced tillage intensity). Overall, manure application was the most effective practice for improving soil health, with reduced tillage intensity also effective for improving several soil health indicators.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"466 ","pages":"Article 117674"},"PeriodicalIF":6.6,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974842","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 : 2026-01-12DOI: 10.1016/j.geoderma.2025.117669
Shijie He , Beilei Wei , Hao Guo , Huarong Lin , Ruixuan Zhu , Xiaoqi Zhang , Shunting He , Yongfeng Sun , Shengsen Zhou , Andong Cai , Ziting Wang , Zhigang Huang
Agricultural soil acidification affects 40–70% of croplands worldwide and is intensifying with increasing nitrogen fertilization. Although nitrogen fertilizer-induced acidification is well-documented, the quantitative relationships and thresholds between base cations and exchangeable acids across different soil pH levels remain poorly understood. This study conducted a meta-analysis of 2,348 field trials from 157 sites worldwide, quantifying the dynamics of base cations (K+, Ca2+, Mg2+) and exchangeable acids in acidic and neutral soils under long-term nitrogen fertilization. It aims to: (1) quantify nitrogen effects on base cations and exchangeable acids; (2) evaluate the relationship between base cation loss and pH decline in soils with different pH values; and (3) explore how organic matter alleviates exchangeable acids increase. The results showed that under nitrogen fertilization, the exchangeable K+, Ca2+, and Mg2+ decreased significantly in acidic soils by 20.3%, 48.6%, and 43.3%, respectively, but showed relative lower decreases in neutral soils by 17.9%, 14.5%, and 6.3%, respectively. In addition, the exchangeable acid content in acidic soils increased significantly by 116.5%, which was much higher than that in neutral soils (35.7%). Subgroup analyses revealed that the accumulation of exchangeable acids could be effectively inhibited when the soil organic matter content exceeded 25.0 g/kg; moreover, the addition of calcium was of great significance for the retention of soil organic matter. This study emphasizes that acidic soils are more sensitive to nitrogen fertilization than neutral soils and more susceptible to soil acidification. These findings are crucial for understanding the acidification threshold of nitrogen fertilizer application, accumulative effects of fertilization time, and dynamic equilibrium between base cations and exchangeable acids in soils with different pH values. They also provide scientific evidence for quantifying the threshold of organic matter content for acidification relief and mitigating soil acidification caused by nitrogen fertilization.
{"title":"Nitrogen fertilization induces greater loss of base cations and accumulation of exchangeable acids in acidic soils than in neutral soils","authors":"Shijie He , Beilei Wei , Hao Guo , Huarong Lin , Ruixuan Zhu , Xiaoqi Zhang , Shunting He , Yongfeng Sun , Shengsen Zhou , Andong Cai , Ziting Wang , Zhigang Huang","doi":"10.1016/j.geoderma.2025.117669","DOIUrl":"10.1016/j.geoderma.2025.117669","url":null,"abstract":"<div><div>Agricultural soil acidification affects 40–70% of croplands worldwide and is intensifying with increasing nitrogen fertilization. Although nitrogen fertilizer-induced acidification is well-documented, the quantitative relationships and thresholds between base cations and exchangeable acids across different soil pH levels remain poorly understood. This study conducted a meta-analysis of 2,348 field trials from 157 sites worldwide, quantifying the dynamics of base cations (K<sup>+</sup>, Ca<sup>2+</sup>, Mg<sup>2+</sup>) and exchangeable acids in acidic and neutral soils under long-term nitrogen fertilization. It aims to: (1) quantify nitrogen effects on base cations and exchangeable acids; (2) evaluate the relationship between base cation loss and pH decline in soils with different pH values; and (3) explore how organic matter alleviates exchangeable acids increase. The results showed that under nitrogen fertilization, the exchangeable K<sup>+</sup>, Ca<sup>2+</sup>, and Mg<sup>2+</sup> decreased significantly in acidic soils by 20.3%, 48.6%, and 43.3%, respectively, but showed relative lower decreases in neutral soils by 17.9%, 14.5%, and 6.3%, respectively. In addition, the exchangeable acid content in acidic soils increased significantly by 116.5%, which was much higher than that in neutral soils (35.7%). Subgroup analyses revealed that the accumulation of exchangeable acids could be effectively inhibited when the soil organic matter content exceeded 25.0 g/kg; moreover, the addition of calcium was of great significance for the retention of soil organic matter. This study emphasizes that acidic soils are more sensitive to nitrogen fertilization than neutral soils and more susceptible to soil acidification. These findings are crucial for understanding the acidification threshold of nitrogen fertilizer application, accumulative effects of fertilization time, and dynamic equilibrium between base cations and exchangeable acids in soils with different pH values. They also provide scientific evidence for quantifying the threshold of organic matter content for acidification relief and mitigating soil acidification caused by nitrogen fertilization.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"466 ","pages":"Article 117669"},"PeriodicalIF":6.6,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145956994","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 : 2026-01-12DOI: 10.1016/j.geoderma.2026.117680
Wei Peng , Lin Liu , Meng Tian , Xiaomeng Yao
The growing demand for studying coupled hydrothermal transport processes in layered soils comes with a need for accurate estimations of thermal properties using the heat pulse (HP) sensor. In the case where a HP sensor is installed vertically in a double-layered soil with the sensor crossing a soil horizon interface, its measurements are affected by different upper and lower layered properties. This study combined laboratory and numerical experiments to quantify the effect of the soil horizon interface on HP measurements, and to develop a parameterized cylindrical perfect conductor (PCPC) model that accounts for the interface position and layered properties. Results indicated that the effect of the layered soil properties on HP measurements depended on the soil horizon interface position, specifically when the soil horizon interface was within 15 mm vertically above or below the thermocouples in the HP sensor. A sigmoid function was used to quantify the effects of soil layer properties and soil horizon interface position on HP measurements. The developed PCPC model, based on the sigmoid function, exhibited strong agreement with the numerical simulations, yielding soil thermal property estimates all within a maximum relative error of −3.1%. The PCPC model effectively captured the combined effects of soil horizon interface and thermal properties of soil layers on the HP measurements in a double-layered soil system. This model provides a theoretical basis for the inversion of soil thermal property in such a double-layered soil environments with a HP sensor vertically crossing a soil horizon interface.
{"title":"Analysis of soil thermal property measurements in double-layered soils with the heat pulse sensor vertically crossing a soil horizon interface","authors":"Wei Peng , Lin Liu , Meng Tian , Xiaomeng Yao","doi":"10.1016/j.geoderma.2026.117680","DOIUrl":"10.1016/j.geoderma.2026.117680","url":null,"abstract":"<div><div>The growing demand for studying coupled hydrothermal transport processes in layered soils comes with a need for accurate estimations of thermal properties using the heat pulse (HP) sensor. In the case where a HP sensor is installed vertically in a double-layered soil with the sensor crossing a soil horizon interface, its measurements are affected by different upper and lower layered properties. This study combined laboratory and numerical experiments to quantify the effect of the soil horizon interface on HP measurements, and to develop a parameterized cylindrical perfect conductor (PCPC) model that accounts for the interface position and layered properties. Results indicated that the effect of the layered soil properties on HP measurements depended on the soil horizon interface position, specifically when the soil horizon interface was within 15 mm vertically above or below the thermocouples in the HP sensor. A sigmoid function was used to quantify the effects of soil layer properties and soil horizon interface position on HP measurements. The developed PCPC model, based on the sigmoid function, exhibited strong agreement with the numerical simulations, yielding soil thermal property estimates all within a maximum relative error of −3.1%. The PCPC model effectively captured the combined effects of soil horizon interface and thermal properties of soil layers on the HP measurements in a double-layered soil system. This model provides a theoretical basis for the inversion of soil thermal property in such a double-layered soil environments with a HP sensor vertically crossing a soil horizon interface.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"466 ","pages":"Article 117680"},"PeriodicalIF":6.6,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145956993","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 : 2026-01-10DOI: 10.1016/j.geoderma.2025.117665
Chunyu Hou , Shangwen Xia , Xuan Liu , Jiaojiao Jiao , Yi Xiong , Hong Chen , Changwei Ma , Jianping Wu
Plant-soil interactions in terrestrial ecosystems profoundly shape the structure and function of belowground communities. Soil nematodes play a vital role in facilitating key belowground ecological processes, however, it remains poorly understood how different plant phenological functional types regulate their community composition and function in tropical forest soils. To address this, we selected three tropical deciduous species—Terminalia bellirica, Melia azedarach, and Albizia lucidior—and three tropical evergreen species—Castanopsis indica, Trema orientalis, and Syzygium jambos—for a two-year common garden pot experiment in Xishuangbanna Tropical Botanical Garden. We evaluated soil physicochemical properties, leaf functional traits, the nematode abundance and biomass, and their function (energy flux). Our results showed that evergreen species had higher aboveground biomass, leaf thickness, soil dissolved organic carbon, and soil total phosphorus compared to deciduous species. Furthermore, evergreen species exhibited greater abundance, biomass, and energy flux than deciduous species, with increases of 69.12 %, 93.47 %, and 107.55 % for herbivores, and increases of 46.51 %, 27.72 %, and 68.46 % for the total nematodes. Although herbivores abundance positively contributed to total energy flux, this effect was indirectly modulated by plant aboveground biomass and soil dissolved organic carbon. Our findings demonstrate that phenological functional types regulate herbivores by altering the resource quantity available to the soil food web, consequently shaping the community structure of soil nematodes and influencing the energy flow patterns. Based on this common garden pot experiment, we conclude that evergreen species enhance the abundance of herbivores and total soil nematodes, while simultaneously increasing soil carbon storage potential, relative to deciduous species.
{"title":"Plant phenological functional types shape soil nematode abundance and function by regulating aboveground biomass and soil dissolved organic carbon in tropical Xishuangbanna","authors":"Chunyu Hou , Shangwen Xia , Xuan Liu , Jiaojiao Jiao , Yi Xiong , Hong Chen , Changwei Ma , Jianping Wu","doi":"10.1016/j.geoderma.2025.117665","DOIUrl":"10.1016/j.geoderma.2025.117665","url":null,"abstract":"<div><div>Plant-soil interactions in terrestrial ecosystems profoundly shape the structure and function of belowground communities. Soil nematodes play a vital role in facilitating key belowground ecological processes, however, it remains poorly understood how different plant phenological functional types regulate their community composition and function in tropical forest soils. To address this, we selected three tropical deciduous species—<em>Terminalia bellirica</em>, <em>Melia azedarach</em>, and <em>Albizia lucidior</em>—and three tropical evergreen species—<em>Castanopsis indica</em>, <em>Trema orientalis</em>, and <em>Syzygium jambos</em>—for a two-year common garden pot experiment in Xishuangbanna Tropical Botanical Garden. We evaluated soil physicochemical properties, leaf functional traits, the nematode abundance and biomass, and their function (energy flux). Our results showed that evergreen species had higher aboveground biomass, leaf thickness, soil dissolved organic carbon, and soil total phosphorus compared to deciduous species. Furthermore, evergreen species exhibited greater abundance, biomass, and energy flux than deciduous species, with increases of 69.12 %, 93.47 %, and 107.55 % for herbivores, and increases of 46.51 %, 27.72 %, and 68.46 % for the total nematodes. Although herbivores abundance positively contributed to total energy flux, this effect was indirectly modulated by plant aboveground biomass and soil dissolved organic carbon. Our findings demonstrate that phenological functional types regulate herbivores by altering the resource quantity available to the soil food web, consequently shaping the community structure of soil nematodes and influencing the energy flow patterns. Based on this common garden pot experiment, we conclude that evergreen species enhance the abundance of herbivores and total soil nematodes, while simultaneously increasing soil carbon storage potential, relative to deciduous species.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"466 ","pages":"Article 117665"},"PeriodicalIF":6.6,"publicationDate":"2026-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145941327","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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