Geoderma最新文献

{"title":"Effects of wildlife conservation and land use intensification on heterotrophic soil respiration and temperature sensitivity (Q10) in semiarid savannas","authors":"A. Sandhage-Hofmann ,&nbsp;J. Lenzen ,&nbsp;K. Frindte ,&nbsp;A. Angombe ,&nbsp;W. Amelung","doi":"10.1016/j.geoderma.2025.117171","DOIUrl":"10.1016/j.geoderma.2025.117171","url":null,"abstract":"<div><div>Increasing global temperatures promote heterotrophic soil respiration (Rh) and subsequent carbon losses. In addition, greater variability in precipitation leads to more frequent rainfall following dry periods, resulting in a ’pulse’ of microbial activity and carbon release known as the Birch effect, especially in dry regions. But the effect of wildlife conservation and landuse intensification on Rh and Q10 in savanna systems is almost unknown. We hypothesized that i) the Rh pulse after rewetting (“Birch” effect) contributes notably to carbon losses in semi-arid regions, ii) conservation with increasing elephant numbers leads to higher Rh and lower Q10 values compared to rangeland and cropland, iii) modulated locally by habitat type (subcanopy, grass, bare patch), and iv) explained by microbial community composition. We sampled topsoils (0–10 cm) from different habitat types in high and low elephant density plots, croplands, and rangelands in savanna woodlands of the Zambezi region, Namibia. The samples were incubated at different temperatures (20-40° C) using a Respicond® apparatus. Microbial biomass and associated community composition were analyzed by DNA analysis. Immediately after rewetting, carbon losses were substantial and amounted to 200 g CO₂-C day^-1ha⁻¹. High elephant densities had the highest Rh at 25° C (1.21 µg CO₂ g^-1h⁻¹) relative to other land uses (mean 0.75 µg CO₂ g^-1h⁻¹) and significantly higher qPCR copy numbers. Rh was similar under different habitat types. The mean Q10 value during the growing season was comparable under cultivation and high elephant density (∼2.3), exceeding fixed values of land surface models. Warming increased Rh from 0.6 µg CO₂ g^-1h⁻¹ at 20° C by a mean factor of 2.6 at 40° C, with the highest increase at high elephant densities (factor 3.4). Generalized linear mixed models identified contents of nitrogen, silt, pH, and land use type as main predictor variables, explaining 57 % of Rh variability. We conclude that savanna soil’s vulnerability to climate warming is comparable between conservation and intensification but that carbon losses due to warming will be highest under wildlife conservation with high elephant densities.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"454 ","pages":"Article 117171"},"PeriodicalIF":5.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143020009","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Response of root- and soil-associated AM fungi to nitrogen addition and simulated drought in a Chinese fir plantation","authors":"Jiamian Shi ,&nbsp;Xiaojie Li ,&nbsp;Ge Song ,&nbsp;Shengsheng Jin ,&nbsp;Luhong Zhou ,&nbsp;Maokui Lyu ,&nbsp;Jinsheng Xie ,&nbsp;Yalin Hu ,&nbsp;Hang-Wei Hu ,&nbsp;Ji-Zheng He ,&nbsp;Yong Zheng","doi":"10.1016/j.geoderma.2025.117176","DOIUrl":"10.1016/j.geoderma.2025.117176","url":null,"abstract":"<div><div>Global change factors like atmospheric nitrogen (N) deposition and drought pose threats to forest ecosystem including soil microbial diversity. However, how arbuscular mycorrhizal (AM) fungi associated with tree respond to N deposition and drought remains largely unknown. Here root- and soil-inhabiting AM fungi were examined in a field experiment involving N addition and simulated drought (precipitation exclusion) in a Chinese fir (<em>Cunninghamia lanceolata</em>) plantation. The results showed that precipitation exclusion significantly reduced AM fungal intraradical colonization rate in summer, while N addition had no significant effect on AM fungal morphological traits of intraradical colonization rate, hyphal and spore densities. However, seasonal changes significantly affected AM fungal morphological traits, with higher values were observed in summer than in winter. Neither N addition nor drought significantly affected AM fungal diversity or community composition, but AM fungal communities exhibited pronounced seasonal differences. In winter, both root- and soil-associated AM fungal community composition significantly correlated with the ratio of microbial biomass carbon and phosphorus (MBC/MBP), while in summer AM fungal communities were primarily associated with MBP and DOC. These findings highlight the importance of accounting for interaction of N addition and drought, and seasonal response difference on AM fungi in subtropical forest ecosystems.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"454 ","pages":"Article 117176"},"PeriodicalIF":5.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143020010","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Using near-infrared spectroscopy to estimate soil water retention curves with the van Genuchten model","authors":"Youssef Fouad,&nbsp;Inès Soltani,&nbsp;Christophe Cudennec,&nbsp;Didier Michot","doi":"10.1016/j.geoderma.2025.117175","DOIUrl":"10.1016/j.geoderma.2025.117175","url":null,"abstract":"<div><div>Hydraulic properties of unsaturated soils are essential for understanding hydric functioning and solving flow and mass-transfer problems in the vadose zone. One of the best-known models for representing the experimental soil–water retention curve, which describes the matric potential (h) as a function of the water content (θ) of a soil horizon, is the van Genuchten (VG) model. It requires four parameters whose values vary by soil type: residual water content (θ_r), saturated water content (θ_s), the inverse of the air-entry pressure (α) and a shape parameter (n). The main objective of this study was to show the relevance of using near-infrared (NIR) spectroscopy to estimate the parameters of the VG model, based on the relation established between the soil water spectral index (SWSI) and θ (Soltani et al., 2019a). Based on this approach, the effective saturation of VG equals the effective SWSI. We applied the approach to 25 soil samples collected from topsoil and subsoil horizons in Brittany (western France), which exhibited high variability in texture and soil organic carbon content ranging from 0.07 % to 6.23 %. The results showed that i) the NIR-spectroscopy approach was relevant for estimating hydraulic parameters θ_s, α and n of the VG model and ii) the parameters obtained from a VG-like equation based on the relation between h and SWSI predicted values of θ of the soil–water retention curve that were similar to observed values, with a root-mean-square error of 0.031 and 0.045 cm³cm⁻³ for topsoil and subsoil horizons, respectively. The method was thus more accurate for topsoil horizons.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"454 ","pages":"Article 117175"},"PeriodicalIF":5.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143020011","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Freeze-thaw carry-over effect promotes decomposition of recalcitrant carbon in peatlands by nitrogen limitation","authors":"Jiawen Yan ,&nbsp;Lianxi Sheng ,&nbsp;Xiaofei Yu ,&nbsp;Shanshan Ding ,&nbsp;Yongen Min ,&nbsp;Hongyan Shen ,&nbsp;Yuanchun Zou","doi":"10.1016/j.geoderma.2025.117182","DOIUrl":"10.1016/j.geoderma.2025.117182","url":null,"abstract":"<div><div>Peatlands are pivotal in global carbon sequestration initiatives. However, studies of winter ecological factors and their subsequent effects on soil carbon–nitrogen (C-N) coupling processes remain limited, particularly amidst altering snowpack conditions due to climate change. Here, an in situ field experiment focusing on snowpack manipulation (presence and absence) was conducted within a northern peatland, China. The N functional groups and availability, bacterial community’s structure, succession and metabolic function, and carbohydrate-active enzymes (CAZymes) were determined at 0–30 cm (topsoil) and 30–60 cm (subsoil) employing synchrotron radiation X-ray absorption near-edge structure (XANES) and metagenomic sequencing technologies. The findings revealed that snowpack absence augmented the number of freeze–thaw cycles by 9 times, causing the subsoil that initially did not experience freeze–thaw cycles to undergo 17 cycles. This amplification of freeze–thaw cycles significantly influenced soil N processes during the freeze–thaw period and subsequent seasons. Specifically, it resulted in a 40.2 % and 1.8 % increase in the metabolic potential of denitrification in the topsoil and subsoil, respectively. Concurrently, there was a reduction in inorganic N content by 4.1 % and 4.4 % in the topsoil and subsoil, respectively. Furthermore, the diminished N availability (ammonium and inorganic N) intensifying soil N limitation subsequently altered microbial assembly processes. This shift led to a significant increase in the abundance of CAZymes encoding the decomposition of lignin (19.2 % and 4.8 %), chitin (4.8 % and 1.4 %), and murein (9.0 % and 0.8 %) in the topsoil and subsoil. Additionally, the content of pyridine, primarily derived from the decomposition of lignin and microbial cell walls, increased by 2.2 % and 1.9 % at two studied depths under snowpack absence conditions. These results uncover a cascading relationship between snowpack conditions, N availability, and the decomposition of recalcitrant carbon in peatland soils, highlighting the need for further comprehensive studies in this domain.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"454 ","pages":"Article 117182"},"PeriodicalIF":5.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143020251","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Low-severity wildfire prevents catastrophic impacts on fungal communities and soil carbon stability in a fire-affected Douglas-fir ecosystem","authors":"Timothy J. Philpott ,&nbsp;Gabriel Danyagri ,&nbsp;Brian Wallace ,&nbsp;Mae Frank","doi":"10.1016/j.geoderma.2025.117189","DOIUrl":"10.1016/j.geoderma.2025.117189","url":null,"abstract":"<div><div>The growing frequency, extent and severity of wildfire is destabilizing carbon sinks in western North America, underscoring an urgent need to better understand fire impacts on soil carbon stocks, carbon stability, and fungi that regulate soil carbon cycling. Here, we examined the effects of wildfire two years post-burn on soil carbon and fungal communities across a fire severity gradient in Douglas-fir forests in central British Columbia, Canada. We observed no significant differences in soil carbon or fungal community composition between low-severity and unburned stands. In contrast, high-severity wildfire resulted in a 49 % reduction in belowground carbon stocks (20.7 Mg C·ha⁻¹), a 91 % decline in ectomycorrhizal fungi, 5- to 27-fold increases in pathogenic fungi, and a proliferation of pyrophilous taxa compared to unburned stands. Carbon was lost primarily as light particulate organic matter, whereas impacts to mineral-associated carbon were muted. Pyrogenic carbon preferentially associated with the mineral fraction, modestly increasing (∼0.15 Mg C·ha⁻¹) the proportion of carbon resistant to decay in this stable fraction. Select helotialean (e.g. <em>Phialocephala fortinii</em>) and other pyrophilous taxa were well-correlated with pyrogenic carbon, suggesting this consortium is well-adapted to decompose persistent carbon and will likely continue to mineralize soil carbon even after high severity wildfire. The markedly higher abundance of pathogenic fungi and reduced ectomycorrhizal abundance in stands affected by high-severity fires pose risks to post-fire recovery, particularly if pathogen proliferation reduces conifer fitness. These results highlight that low-severity wildfires have comparatively muted impacts on soil carbon and fungal communities relative to high-severity wildfires, underscoring the importance of management strategies such as thinning and prescribed burns to mitigate the catastrophic effects of high-severity wildfires.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"454 ","pages":"Article 117189"},"PeriodicalIF":5.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143055179","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermogravimetric data suggest synergy between different organic fractions and clay in soil structure formation","authors":"Ivan Šimkovic,&nbsp;Andrej Hrabovský,&nbsp;Adela Joanna Hamerníková,&nbsp;Silvia Ihnačáková,&nbsp;Pavel Dlapa","doi":"10.1016/j.geoderma.2025.117166","DOIUrl":"10.1016/j.geoderma.2025.117166","url":null,"abstract":"<div><div>Although it has been recognized that soil structure formation affects soil organic carbon (SOC) sequestration, experimental data elucidating the relation between mechanical properties of soil structure and soil organic matter (SOM) stability are lacking. This study assesses the link between aggregate stability and SOM stability in lowland and hilly land soils of Central Europe. Overall, 39 topsoil samples were taken. Besides determining basic properties and nutrient availability, stability of soil aggregates was quantified using wet sieving (WS) and rainfall simulation (RS) procedures. The samples were analyzed by thermogravimetry and differential scanning calorimetry (TG-DSC). Besides significant correlations with basic soil properties and contents of selected nutrients, the aggregate stability data were linked to thermal processes, such as water desorption and SOM degradation. The RS values were significantly correlated (r &gt; 0.7, p &lt; 0.001) with the rate of water desorption (T &lt; 200 °C) and SOM degradation (200 – 570 °C). Observed correlation pattern, with multiple maxima, suggests that aggregate stability is supported by clay and several SOM fractions, each showing different thermal stability. Significant correlations observed bellow 200 °C indicate that properties controlling soil specific surface area (SOM and clay) are important also for the aggregate stability. The 78 % of the variance observed in aggregate stability testing was explained by multilinear regression using weight loss rates recorded at selected temperatures (80, 130, 248, 401 and 455 °C) as predictors. We observed different relations between exothermic energy values, soil aggregate stability and thermal stability of SOM (SOC). Exothermic heat flux normalized with respect to SOC mass (energy density) indicates presence of stable organic fraction, as it showed correlation also with clay, which has positive effect on SOC stabilization. This is in line with the positive correlation between SOC energy density and aggregate stability. On contrary, normalizing the heat with respect to SOM mass indicates the content of labile organic components, as the correlations with clay or aggregate stability were insignificant. The TG-DSC data revealed that hilly land soils are depleted in fresh organic material, which is due to their genesis and the erosion intensified by tillage.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"454 ","pages":"Article 117166"},"PeriodicalIF":5.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143055181","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fast-decaying tree litter reduces the temperature sensitivity of soil carbon decomposition by increasing microbial necromass carbon","authors":"Ruihan Li,&nbsp;Chuankuan Wang,&nbsp;Chunhua Lv,&nbsp;Tao Zhou,&nbsp;Shuang Yin,&nbsp;Zhenghu Zhou","doi":"10.1016/j.geoderma.2025.117185","DOIUrl":"10.1016/j.geoderma.2025.117185","url":null,"abstract":"<div><div>Improvements in stocks and stability of forest soil organic carbon can be achieved through the management of tree species. Given the long lifespan of trees and their role as the keystone species in forested ecosystems, decisions regarding tree species management can have a significant impact on soil carbon balance, with effects that may persist for decades. Here, a common garden experiment involving five temperate tree species in northeast China was conducted to quantify the influence of tree species on soil carbon dynamics, including its fractions (mineral-associated organic carbon, particulate organic carbon, and microbial necromass carbon), microbial properties (biomass and activities), and the temperature sensitivity of soil carbon decomposition (<em>Q</em>₁₀). We observed that the decomposition of high-quality litter by soil microbes resulted in increased microbial biomass but decreased microbial biomass-specific enzyme activities and respiration. Although there was no significant difference in soil carbon among tree species, the sources of soil carbon varied among species. Specifically, tree species producing high-quality litter contributed to elevated microbial and fungal necromass carbon. Microbial necromass carbon was positively correlated with soil mineral-associated organic carbon, although tree species had no significant effect on mineral-associated organic carbon. The <em>Q</em>₁₀ increased with longer litter turnover time, as well as with higher microbial biomass-specific oxidase activity and respiration, but decreased with greater litterfall production, microbial biomass, and microbial necromass carbon. Overall, our findings indicate that fast-decaying tree litter increases soil microbial necromass carbon and decreases <em>Q</em>₁₀. This is the first study to establish a connection between <em>Q</em>₁₀ with microbial necromass carbon using experimental data. Moreover, the tree species-specific origins of soil carbon and their influence on <em>Q</em>₁₀ should be considered when managing forests as carbon sinks in the context of future global warming.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"454 ","pages":"Article 117185"},"PeriodicalIF":5.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143055315","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Land use intensity differently influences soil communities across a range of arable fields and grasslands","authors":"Chenguang Gao ,&nbsp;Johanna E.M. Schild ,&nbsp;Gabriel Y.K. Moinet ,&nbsp;T. Martijn Bezemer ,&nbsp;Franciska T. de Vries ,&nbsp;Jan Hassink ,&nbsp;Nick van Eekeren ,&nbsp;Kevin Beentjes ,&nbsp;Peter M. van Bodegom","doi":"10.1016/j.geoderma.2025.117201","DOIUrl":"10.1016/j.geoderma.2025.117201","url":null,"abstract":"<div><div>While there is an emerging body of research showing the consequences of land use intensity on soil biodiversity, most studies focus on biodiversity responses to a single or a limited number of agricultural practices in controlled settings or at a single field site, neglecting that multiple practices are simultaneously applied by farmers in real agroecosystems. The combined effects of various agricultural practices have, until now, been largely overlooked in agroecosystems.</div><div>Here, we conducted a field soil sampling campaign on 87 farms with two land use types (39 arable fields and 48 grasslands) to investigate the relationship between land use intensity, determined by various agricultural practices, and multiple soil communities (bacteria, fungi, protists and invertebrates) at regional scales.</div><div>We found that land use intensity influenced the diversity and community composition of various soil taxa differently, and these impacts strongly depended on land use type. Soil fungi were most susceptible to land use intensity in both arable fields and grasslands. Specifically, irrigation and pest control were the main practices shaping soil communities in arable fields, while phosphorus and nitrogen fertilization were the main practices structuring soil communities in grasslands. Furthermore, an increase in land use intensity led to greater soil network complexity in arable fields.</div><div>Our findings reveal regional on-farm patterns of land use intensity effects on various soil communities and identified key agricultural practices that structure soil communities. A key strength of this study is that these patterns can be generalized because the samples were collected from 87 farmlands where multiple agricultural practices were implemented simultaneously. Overall, this work provides a comprehensive perspective on the different responses of multiple soil communities and their associations to land use intensity in agroecosystems.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"454 ","pages":"Article 117201"},"PeriodicalIF":5.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143125148","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mitigation of soil salinity by biochar and halophytes","authors":"Qiang Xu ,&nbsp;Yibin Xu ,&nbsp;Hanji Xia ,&nbsp;Han Han ,&nbsp;Mingsi Li ,&nbsp;Ping Gong ,&nbsp;Chunxia Wang ,&nbsp;Yufang Li ,&nbsp;Pengfei Li ,&nbsp;Hongguang Liu","doi":"10.1016/j.geoderma.2025.117191","DOIUrl":"10.1016/j.geoderma.2025.117191","url":null,"abstract":"<div><div>Biochar is widely recognized as a significant agricultural management practice globally. Nevertheless, its application typically emphasizes incorporation into topsoil, while the potential benefits of biochar interlayers in ameliorating saline wastelands in arid regions remain insufficiently understood. A study was conducted to investigate the impact of biochar interlayers on the dynamics and distribution of water and salt in saline wasteland soils cultivated with <em>Suaeda salsa</em> (<em>S. salsa</em>) during growth and non-growth periods. Over three consecutive years, a field experiment was implemented with four biochar application rates: 0 Mg/ha (CK), 15 Mg/ha (M1), 45 Mg/ha (M2), and 75 Mg/ha (M3). The biochar was uniformly distributed at a depth of 40 cm, and the original soil from the 0–40 cm layer was refilled. The results demonstrate that biochar interlayers reduced groundwater evaporation and minimized surface salt accumulation during the non-growth period, leading to a reduction in soil salinity by 13.14 %–49.62 % in the 0–40 cm layer, with a bimodal salinity distribution pattern observed at 0 cm and 45 cm depths. During the growth period, biochar significantly enhanced water retention and reduced salinity. Water content increased by 0.14 %–18.92 %, and salt content decreased by 24.51 %–36.64 % within the 0–40 cm soil layer, with salt aggregating at 40–60 cm depths. The root system of <em>S. salsa</em> utilized water and salt from the biochar interlayer, resulting in a marked increase in salt content within plant organs. Concentrations of Na⁺, Cl⁻, and SO₄²⁻ decreased, while K⁺, Ca²⁺, and Mg²⁺ levels increased in these organs. The yield of <em>S. salsa</em> improved by 22.12 %–65.92 %, and salt absorption efficiency rose by 30.62 %–85.03 %. However, excessive biochar applications may hinder surface soil desalination and pose risks of secondary salinization. Thus, a moderate biochar application rate of 45 Mg/ha is recommended for effective water retention and salt suppression in saline wastelands.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"454 ","pages":"Article 117191"},"PeriodicalIF":5.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143125353","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Permafrost pore structure and its influence on microbial diversity: Insights from X-ray computed tomography","authors":"Nathan D. Blais ,&nbsp;Joy M. O’Brien ,&nbsp;Hannah Holland-Moritz ,&nbsp;Lauren Farnsworth ,&nbsp;Robyn A. Barbato ,&nbsp;Thomas A. Douglas ,&nbsp;Alexandra Contosta ,&nbsp;Julie Bobyock ,&nbsp;Erin C. Rooney ,&nbsp;Taylor Sullivan ,&nbsp;Jessica Gilman Ernakovich","doi":"10.1016/j.geoderma.2025.117192","DOIUrl":"10.1016/j.geoderma.2025.117192","url":null,"abstract":"<div><div>Soil pore structure plays a critical role in shaping soil microbial communities, which directly influence biogeochemical cycling. A notable impact of soil pore structure on microbial communities is the inverse relationship between microbial diversity and hydrological pore connectivity, where increased hydrological pore connectivity reduces microbial diversity. Although well-studied in temperate systems, the importance of hydrological pore connectivity on soil microbial community diversity in permafrost soils is largely unknown. Although once thought to be devoid of microbial activity, more recent advances demonstrate permafrost is an active ecosystem albeit less than most unfrozen soil. Thus, these principles that govern unfrozen soils could remain impactful in permafrost. In this study, our objective was to quantify permafrost pore structure and determine if the inverse relationship between soil hydrological pore connectivity and microbial diversity persists in permafrost. To address these objectives, we analyzed eight permafrost cores from three distinct sites in Alaska. To quantify soil pore characteristics, we scanned intact permafrost using X-ray computed tomography. The Euler characteristic number was used to measure pore connectivity and serve as a proxy for potential hydrological connectivity, as direct measurement of hydrological connectivity was not possible. DNA and RNA were extracted from the scanned permafrost and analyzed via amplicon sequencing of the 16S region to quantify the total and active microbial community diversity. We found that permafrost soil shares characteristics with temperate soils despite limits in our analytical resolution (i.e., at an instrument scanning resolution of 20 µm, only macro-scale features (&gt;75 µm) could be quantified). For example, we found that pores in the range of 75–1000 µm are the dominant pore size class and a positive relationship between total porosity and pore connectivity. Additionally, we identified pore connectivity as a potential driver of microbial diversity and provided evidence that conditions before the formation of permafrost exert a strong legacy effect on currently observed permafrost microbial diversity. These insights help to explain how soil physical structure acts to influence microbial communities in this extreme environment.</div></div>","PeriodicalId":12511,"journal":{"name":"Geoderma","volume":"454 ","pages":"Article 117192"},"PeriodicalIF":5.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143315819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}