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1. 题目: Regional-scale prediction and assessment of soil organic matter content in the Yuanmou Dry-Hot Valley, Southwest China, using satellite-derived phenological time series and deep learning.
文章编号: N26071719
期刊: Environmental Monitoring and Assessment
作者: Dengdeng Ding, Jida Yang, Sihe Deng, Hongye Zhu, Zhengbo Ma, Chengxiu Fu, Junlang Deng, Dingyun Zhao, Zhen Long, Xiaoyan Wang, Peiwen Yang, Qibin Chen, Qing Zhang
更新时间: 2026-07-17
摘要: The dry-hot valley region is characterized by pronounced topographic relief and a complex land-use mosaic, resulting in strong nonlinearity and fine-scale spatial heterogeneity in soil organic matter (SOM). These characteristics increase the difficulty and uncertainty of remote sensing-based digital soil mapping. Although Yuanmou County has been widely investigated, limited attention has been paid to regional-scale SOM prediction in dry-hot valley ecosystems using long-term satellite-derived phenological dynamics and deep learning approaches. To address this gap, this study integrated 475 topsoil samples, topographic factors, environmental covariates, and multi-year satellite-derived phenology time-series variables to develop a regional-scale SOM prediction and assessment framework in Yuanmou County, Yunnan Province, China. The predictive performance of four models was compared, including a convolutional neural network (CNN), a CNN-random forest hybrid model (CNN-RF), a CNN-long short-term memory model (CNN-LSTM), and an attention-augmented CNN-LSTM model (CNN-LSTM-Att). The results showed that model architecture had a substantial influence on SOM prediction accuracy, with overall performance ranked as CNN-LSTM-Att > CNN-LSTM > CNN-RF > CNN. Among the four models, CNN-LSTM-Att achieved the best performance on the independent test set, with R2 = 0.61, RMSE = 2.49 g kg⁻1, and MAE = 1.39 g kg⁻1. The incorporation of temporal modeling and the attention mechanism improved the extraction of dynamic phenological signals associated with SOM formation, resulting in a more refined spatial representation. The CNN-LSTM-Att prediction map clearly identified low-SOM areas along the northern valley corridor and high-SOM zones in the forest-dominated southern and eastern regions, while showing stronger sensitivity to local patches and transitional ecotones. Overall, coupling long-term phenological dynamics with an attention mechanism improved both the predictive accuracy and spatial expressiveness of SOM mapping in complex terrain, providing a useful methodological reference for SOM assessment and precision land management in dry-hot valley regions.

2. 题目: The influence of microplastic type on biochar efficacy in Cd-microplastic co-contaminated soils: divergent impacts of PLA versus PE in pepper
文章编号: N26071718
期刊: Journal of Soils and Sediments
作者: Yanhang Zhong, Yawen Shen, Jingwen Bi, Yuge He, Shushu Liu, Xin Feng, Liangmeng Ni, Zhijia Liu
更新时间: 2026-07-17
摘要: Purpose Microplastics (MPs) and cadmium (Cd) often co-occur in farmland soils, but it remains unclear whether microplastic type changes Cd mobility and the remediation efficacy of biochar. This study compared whether polyethylene (PE) and polylactic acid (PLA) differentially regulate Cd bioavailability, plant uptake, and biochar remediation effect in a soil-pepper system. Materials and methods A pot experiment with pepper (Capsicum annuum L.) was conducted using PE, PLA, Cd, and their combined treatments with or without biochar amendment. Soil properties, plant growth and microbial communities were analyzed. Results Responses were strongly dependent on microplastic type. PLA, especially under PLA + Cd co-contamination, acidified soil, increased exchangeable Cd, suppressed pepper growth, and reduced yield. PE caused much weaker disturbance, and PE + Cd behaved similarly to the Cd treatment. Biochar generally increased soil organic carbon and improved soil enzyme activities and microbial diversity, while reducing exchangeable Cd and plant Cd in Cd- and PE + Cd-treated soils, thereby promoting plant recovery. In contrast, biochar showed limited efficacy under PLA + Cd because persistent acidification maintained high Cd mobility and constrained biological recovery. Conclusions Microplastic type determined both Cd risk and the effectiveness of biochar in co-contaminated soils. PLA enhanced Cd bioavailability through acidification and narrowed the effective remediation window of biochar, whereas PE did not. These findings indicate that identifying microplastic type and managing soil pH are critical for successful remediation of Cd-microplastic co-contaminated soils.

3. 题目: Ambient black carbon and its dependence on in situ stubble burning.
文章编号: N26071717
期刊: Environmental Monitoring and Assessment
作者: Vikas Goel, Ajit Kumar, Anjanay Pandey, Mohd Faisal, Umer Ali, Rakesh Maity, Ravindra Khaiwal, Suman Mor, Vikram Singh, Mayank Kumar
更新时间: 2026-07-17
摘要: Crop residue burning (CRB) in Northern India is a serious concern that poses substantial health risks and deteriorates air quality in the Indo-Gangetic Plain (IGP) region via regional transport. Despite governmental regulations and various interventions, the practice remains prevalent. In this study, we investigate the influence of CRB on ambient black carbon (BC) level in rural areas of Punjab during the post-monsoon period. BC source contributors were quantified using Aethalometer model (AM) and positive matrix factorization (PMF) approaches. Interestingly, despite the distinct mathematical framework of these two models, their results showed good agreement. Although the measurements were conducted in the agricultural field, CRB contributed on average 48% to the total BC, periodically exceeding 90% during the active burning hours (1:00 PM-6:00 PM), resulting in strong diurnal variation. In addition to the CRB several other BC sources, e.g. traffic emissions (20.2%), power plant emissions (24.0%), waste incineration (2.0%), and a Pb-rich industrial factor (6.1%) were also quantified. The BC concentration measured during the study ranged from 1.45 to 85.0 µg/m3 with an average of 12.6 µg/m3. Absorption Ångström exponent (AAE) was also calculated and observed to be 1.7 ± 0.3, with hourly variations ranging from 1.1 to 2.4, suggesting a significant influence of CRB. Furthermore, spectral variation in absorption characteristics of BC and brown carbon (BrC) was also evaluated, providing insight into the optical properties of fresh biomass-burning carbonaceous aerosols. The study highlights the persistent dominance of CRB emissions in shaping rural aerosol composition. Moreover, when transported by prevailing winds, these aerosols substantially influence air quality across the IGP. Forward wind trajectory analysis further demonstrates that air masses originating in Punjab frequently move toward the IGP region, supporting the observed regional impact of CRB emissions. These findings provide quantitative evidence to support targeted policy interventions, including stricter enforcement of crop residue burning bans, wider adoption of sustainable residue management alternatives, and regionally coordinated air quality mitigation strategies across the IGP.

4. 题目: How does moisture content regulate EPS dynamics and microbial interactions to mediate erosion resistance in sewer sediments?
文章编号: N26071716
期刊: Environmental Research
作者: Bingchan Jia, Xinyu Zhao, Meili Zhang, Jian Wang, Xinyue Yuan, Zhaoxia Xue, Jingyang Luo, Xindi Chen, Qian Feng
更新时间: 2026-07-17
摘要: The erosion resistance of sewer sediments is a key determinant of hydraulic efficiency and flood risks in urban drainage systems. In real sewer networks, sediment moisture content fluctuates substantially due to intermittent drainage, seasonal variation, and storm inflow pulses, yet its influence on microbially mediated sediment stability remains poorly understood. This study systematically investigated how moisture content regulates extracellular polymeric substances (EPS) dynamics, microbial community structure, and microbial interactions in sewer sediments across a moisture range of 10.10-59.09%. Sediments at intermediate moisture levels (29.17-40.91%) exhibited the highest erosion resistance, with EPS content strongly positively correlated with critical shear stress (R2 = 0.92). Moderate moisture also enriched key EPS-producing taxa and promoted a more cooperative microbial interaction pattern, thereby enhancing the capacity of the community to withstand scouring disturbance. These findings introduce the concept of adaptive moisture window, representing the moisture range where microbial activity and EPS secretion are most favorable for sediment stability. This framework provides new insights into predicting sediment cohesion under variable sewer moisture regimes and offers new guidance for adaptive sediment management in urban drainage systems.

5. 题目: Improving monitoring of microplastics in soils and biosolids using near-infrared spectroscopy: the effect of organic matter.
文章编号: N26071715
期刊: Journal of Environmental Management
作者: Luana Circelli, Erika Di Iorio, Zhongqi Cheng, Ruggero Angelico, Martina Cusano, Claudio Colombo
更新时间: 2026-07-17
摘要: Microplastics (MPs) are emerging contaminants ubiquitously present in the environment, yet their rapid quantification in complex matrices such as soils and biosolids remains challenging because of spectral interference from organic matter (OM). This study investigates, for the first time, how high OM contents influence the spectral detectability and machine-learning-based quantification of high-density polyethylene (HDPE) and polystyrene (PS) polymers (at 0-8% v/v) in soils and biosolids. Pre-processed NIR spectra were analysed using partial least squares-discriminant analysis (PLS-DA) to identify MP- and OM-related wavelength regions via variable importance in projection (VIP), which were subsequently used as inputs for four regression algorithms (PLS, support vector machines, random forest and custom neural network). In soils with low OM (0.78-1.23%), HDPE and PS produced polymer-specific absorption features and were predicted with excellent accuracy (up to R2 = 0.96 and residual prediction deviation, RPD = 5.19), using a relatively small set of VIP-selected wavelengths. In biosolids with very high OM (64-72%), polymer bands were partially masked, and VIP scores shifted towards OM-dominated regions. However, prediction performance remained robust, especially for HDPE with neural network model (R2 = 0.98, RPD = 6.41). Overall, although the OM strongly influenced the spectral regions driving model predictions and partially reduced discrimination among MP concentration levels, it does not prevent accurate quantification of MPs when appropriate variable selection and machine-learning strategies were applied. These findings demonstrate that NIR spectroscopy coupled with targeted variable selection and advanced regression can provide robust, non-destructive estimation of MP contamination in OM-poor soils and OM-rich biosolids, highlighting key spectral features to prioritise in future studies targeting natural organic-rich samples with low-MP concentration.

6. 题目: Raman imaging of the phycosphere reveals sharp gradients of organic matter exuded by single phytoplankton cells
文章编号: N26071714
期刊: Proceedings of the National Academy of Sciences of the United States of America
作者: Zachary C Landry, Riccardo Foffi, Valerio Anelli, Paolo Arosio, Marcos Gil-Garcia, Richard J Henshaw, Oliver Müller, Giacomo Paccagnan, Timo N Schneider, Carsten J Schubert, Jonasz Słomka, Kang Soo Lee, Tomaso Zambelli, Sophie T. Zweifel, Roman Stocker
更新时间: 2026-07-17
摘要: Phytoplankton cells exude a wide array of chemicals in the water column, generating a localized microenvironment known as the phycosphere. Although it is now well accepted that the phycosphere mediates interactions between phytoplankton and bacteria, the chemical gradients around individual phytoplankton cells have never been explicitly measured, and their shape has been classically assumed to be set by ideal diffusion. Here we used Raman microspectroscopy to obtain micrometer-scale measurements of the concentration profile of a phytoplankton metabolite (fucoxanthin) around individual phytoplankton cells of different species, having radii between 2.5 and 60 μ m. We found that fucoxanthin concentration decreases more rapidly with distance from the cell than predicted by ideal diffusion, showing that the phycosphere includes compounds whose diffusion is characterized by nonideal effects. We explain this observation using a space-dependent diffusivity model where nonideality arises from viscosity and solubility gradients in the extracellular environment. Our results suggest an onion-structured model of the phycosphere, in which small hydrophilic solutes that obey ideal diffusion generate broad but weak gradients, whereas insoluble compounds are retained within 10 to 20 μ from the phytoplankton cell surface and yield steep gradients of organic matter. These observations, supported by evidence that fucoxanthin can act as an effective chemoattractant for marine bacteria, show the existence of strong and highly localized chemical cues with potentially far-reaching impacts on microbial interactions in aquatic environments. These findings highlight the importance of directly measuring the microscale chemical landscape experienced by marine microbes.

7. 题目: The Aridity Threshold of Soil Organic Carbon Density Along the Climate Aridity Gradient in the Alpine Ecosystem of the Qinghai‐Tibetan Plateau
文章编号: N26071713
期刊: Land Degradation & Development
作者: Qiao Cui, Zongxing Li, Xufeng Wang, Juan Gui, Baijuan Zhang, Yunying Wang
更新时间: 2026-07-17
摘要: Soil organic carbon density (SOCD) is a key indicator for evaluating the stability of soil carbon pools, especially in alpine ecosystems that are sensitive to climate change. However, research on the response of SOCD to different aridity gradients is still limited. Therefore, we conducted extensive sampling along different aridity gradients of the Qinghai‐Tibetan Plateau to study how SOCD varies with aridity gradients and how environmental factors drive changes in SOCD under different aridity gradients. The study has found that the SOCD at depths of 0–100 cm on the Qinghai‐Tibetan Plateau ranges from 0.39 to 78.12 kg C m −2 . Meanwhile, the SOCD is higher in the more humid southeastern region than in the more arid northwestern region. Topography, climate, and vegetation factors jointly regulate the distribution of SOCD. The SOCD shows a nonlinear variation trend and decreases with the increase of aridity; the key aridity threshold is 0.66. The altitude, aridity, mean annual temperature (MAT), and normalized vegetation index (NDVI) are the main drivers of SOCD below this threshold (low aridity gradient). Moreover, the SOCD is primarily affected by the NDVI and MAT above this threshold (high aridity gradient). The above research results emphasize the differences in SOCD across aridity gradients, suggesting that it may be possible to mitigate the negative impact of aridification on soil organic carbon by increasing vegetation coverage in areas with high and low aridity gradients.

8. 题目: Iron Oxide Types Determine the Regulatory Effects of Biochar on Carbon Emissions from Arsenic-Contaminated Soils
文章编号: N26071712
期刊: Water, Air, & Soil Pollution
作者: Qi Li, Wenjing Li, Yanyan Lu, Sada Tanzil, Wan Yang, Muhammad Mahroz Hussain, Shengsen Wang
更新时间: 2026-07-17
摘要: Arsenic (As) remediation in flooded paddy soils through iron (Fe) redox cycling can be influenced by carbon-based amendments, yet the CO2 emission in this process remain unclear. This study evaluated the effects of Fe oxides with contrasting crystallinity, goethite (Gt) and ferrihydrite (Fh), with or without biochar (BC) amendment, on As immobilization, geochemical fractionation and microbial-carbon dynamics from As-contaminated paddy soil under reduced conditions. The results showed that Fh and Gt, with BC addition, significantly (p < 0.05) reduced As bioavailability by 87.5% (0.39 mg kg−1) and 76.6% (0.73 mg kg−1), respectively, compared to control. Partial Least Squares Path Modeling revealed a strong negative direct effect of Fe-oxides on As (β = -3.86), confirming their role as the principal gatekeepers for As sequestration. Iron oxides application increased the CO₂ flux; however, a dramatic decrease was observed with BC application to Fe oxide-treated soils. This elucidates that the increased C emission from As-contaminated soil induced by Fh or Gt can be compromised by BC application, although the extent of reduction depends on the type of Fe oxide. Microbial community analysis revealed increased relative abundance of Pseudarthrobacter and Anaerolinea in Fh-amended soils, highlighting their potential role in carbon cycling processes. Fe oxides recruited Fe(III)-reducing bacterial guilds (Firmicutes, Proteobacteria) to drive CO₂ emissions, whereas BC addition suppressed reshaped functional potentials of these taxa, explaining the trade-off between reduced CO₂ and As immobilization. This study provides an insight towards the mitigation of As contamination and GHG emission through co-application of Fe oxides and BC as a sustainable approach.

9. 题目: Abiotic Pathways Bridge the Molecular Transformation from Terrestrial to Lacustrine Dissolved Organic Matter in Shallow Lakes.
文章编号: N26071711
期刊: Environmental Science & Technology
作者: Xueyan Liu, Kangping Cui, Yiling Yao, Hongjia Yao, Minshu Cui
更新时间: 2026-07-17
摘要: Terrestrial dissolved organic matter (DOM) is a dominant allochthonous input to shallow lakes but exhibits low bioavailability due to prior microbial degradation and complex aromatic structures. In contrast, lacustrine DOM is more saturated and structurally homogeneous, implying in-lake transformation. Herein, we investigated the abiotic transformation of terrestrial and lacustrine DOM using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), linkage reaction classification, and XGBoost-SHAP machine learning. Under coupled simulated sunlight and MnO2 exposure, terrestrial DOM is more prone to dearomatization and partial oxidation, with limited carbon backbone cleavage due to stable condensed aromatic frameworks. Conversely, while partial oxidation remains a primary pathway, aliphatic-rich lacustrine DOM readily undergoes carbon backbone fragmentation. Notably, MnO2 acts as an electron acceptor and reactive oxygen species regulator, mitigating direct photosensitized carbon backbone cleavage while enhancing oxidation and structural complexity. Machine learning confirms that, despite distinct origins, both DOM types exhibit consistent shifts toward higher oxygenation and aliphatic character. Furthermore, this analysis provides new insights, identifying the nitrogen content and DBE/O as universal indicators of DOM reactivity. Ultimately, abiotic processes impose common molecular constraints, guiding DOM transformation along partially convergent pathways and driving structurally distinct DOM pools toward a shared chemical fate.

10. 题目: Thermochemical processing of sewage sludges: Comparative analysis of hydrochars and biochars for sustainable phosphorus recovery.
文章编号: N26071710
期刊: Science of the Total Environment
作者: Mozhdeh Alipoursarbani, Hossein Asadi, Christian Abendroth
更新时间: 2026-07-17
摘要: Securing sustainable phosphorus (P) resources from municipal sewage sludge is critical for circular nutrient management. This study investigates the effects of hydrothermal carbonization (HTC, 180 °C) and pyrolysis (450 °C and 600 °C) on two different sewage sludges: Stabilized Sewage Sludge (SSS) derived from an extended aeration activated sludge (EAAS) system, and Sludge Cake (SC) obtained from an anaerobic-anoxic-oxic (A/A/O) treatment process. Feedstock origin strongly governed phosphorus speciation, transformation pathways, and char properties during thermochemical processing. The two raw sludges were influenced by their original treatment, with SSS showing higher total phosphorus (TP = 39.04 mg g-1) but a lower Ca/P molar ratio (0.20) compared with SC (TP = 26.10 mg g-1, Ca/P = 0.50), indicating distinct P partitioning between mineral and organic fractions. Hydrochars (SH from SSS, CH from SC) showed moderate total P concentrations (TP) and retained some organic P (OP), whereas pyrolysis produced biochars with higher TP: 59.7 mg g-1 in SB600 (SSS) and 46.0 mg g-1 in CB600 (SC). OP decreased significantly from 6.38 mg g-1 (SSS) and 8.15 mg g-1 (SC) to below 2.5 mg g-1, while inorganic P (IP) became dominant. In SSS biochars, apatite phosphorus (AP) was the main fraction, while in SC biochars, non-apatite inorganic P (NAIP) remained significant. These contrasting behaviors are attributed to feedstock-dependent mineral compositions, where Fe- and Al-associated fractions in SSS promoted conversion of NAIP into AP, whereas the higher initial Ca content in SC favored NAIP retention. Solid-state 31P NMR confirmed that orthophosphate (Ortho-P) is the main P species, highlighting its bioavailability and thermal stability. Pyrolysis increased carbonization, decreased H/C and O/C ratios (down to 0.44 and 0.33 at 600 °C), and generated highly porous, thermally stable chars. Overall, these results demonstrate that both sludge type and thermochemical pathway critically influence char properties and phosphorus forms.

11. 题目: Influence of land use on soil properties and organic carbon pool distribution in deep soil layers of subtropical India.
文章编号: N26071709
期刊: Environmental Monitoring and Assessment
作者: Shrikant Badole, Ashim Datta, Krishna Chaitanya Anantha, Biswapati Mandal, P S Bodake
更新时间: 2026-07-17
摘要: Climate change poses serious concern for humanity. Globally, land-use change contributes nearly 20% of the total greenhouse gas (GHG) emissions. Understanding the vertical distribution of soil organic carbon (SOC) pools is crucial for evaluating regional and global C storage potential and for anticipating the impacts of climate change, yet studies on this aspect remain limited. In the present investigation, five land use types were selected - three agricultural systems with varied cropping intensities (CI), namely 300% CI (rice-potato-jute), 200% CI (rice-jute), and 100% CI (rice), fallow and forest land dominated by Shorea robusta, Dalbergia sissoo, and Bombax malabaricum. Soil profile samples were collected from 0-0.2, 0.2-0.4, 0.4-0.6, 0.6-0.8, 0.8-1.0, 1.0-1.5, and 1.5-2.0 m depth intervals. With increasing depth, soil pH and bulk density (BD) increased, whereas silt and clay content generally decreased in most land uses. The lowest pH (4.5) and BD (1.19 Mg m-3) were observed under forest land at 0-0.2 m depth, whereas the highest BD (1.61 Mg m-3) and pH (8.0) were obtained in 100% CI at 1.5-2.0 m, and fallow land at 0.8-1.0 m, respectively. Labile SOC fractions decreased with soil depth, whereas the proportion of recalcitrant carbon in the passive pool increased with depth. Overall, forest land stored highest SOC (126.3 Mg C ha-1) followed by fallow land (121.9 Mg C ha-1), while among the agricultural systems, the 300% CI exhibited the maximum SOC stock (89.1 Mg C ha-1) followed by 200% CI (86.1 Mg C ha-1) and 100% CI (56.4 Mg C ha-1) at the 2.0 m soil depth. These findings demonstrate that forest land maintained the highest SOC stocks while among the agricultural systems, diversified cropping systems with 300% CI exhibited greater potential for C sequestration and sustaining soil health in the terai region of subtropical India.

12. 题目: Biochar-earthworm-plant interactions regulate soil organic carbon stabilization and Cd immobilization in vegetable and corn cropping system.
文章编号: N26071708
期刊: Ecotoxicology and Environmental Safety
作者: Cevin Tibihenda, Yiqing Chen, Menghao Zhang, Hesen Zhong, Li Jia, Longhua Wu, Mikael Motelica-Heino, Ying Lu, Chi Zhang
更新时间: 2026-07-17
摘要: A dual strategy for carbon (C) sequestration and Cd remediation was developed by leveraging the synergistic effects of biochar and earthworms on soil organic C transformation and Cd bioavailability. However, the combined capacity of these amendments to simultaneously enhance soil organic C storage and reduce crop Cd uptake, particularly through the regulation of dynamic organic C pools, remains insufficiently understood. A field experiment was conducted to evaluate the individual and combined effects of biochar (600 g plot⁻¹) and earthworms (Amynthas aspergillum; 50 worms plot⁻¹) on soil organic C dynamics and Cd transfer in corn (Zea mays) and vegetables (Brassica campestris). To account for soil heterogeneity, samples were collected from non-planted, bulk, and rhizosphere soil zones. Microbial biomass was highest in corn fields treated with biochar alone, whereas earthworm activity significantly altered microbial community structure, particularly the Gram-positive-to-Gram-negative (G+/G-) and fungal-to-bacterial (F/B) ratios. Distinct soil organic C stabilization patterns were observed between crop systems: vegetable fields exhibited increased mineral-associated organic C (MAOC) and dissolved organic C (DOC), while corn fields promoted particulate organic C (POC) and higher POC/MAOC ratios. Redundancy analysis (RDA) revealed that POC was positively correlated with amorphous Fe and the activities of catalase, urease, and fluorescein diacetate (FDA) hydrolase, whereas MAOC was significantly associated with invertase activity and microbial community ratios (G+/G- and F/B). Partial least squares (PLS) analysis identified POC as the dominant organic C pool, primarily regulated by crop type and mediated by soil chemistry, microbial structure, and Fe oxide forms. Biochar application immobilized Cd by increasing POC content, the POC/MAOC ratio, exchangeable Ca, free Fe, and urease activity, while also promoting more stable Cd fractions, including oxidizable and residual forms. Consequently, biochar reduced Cd uptake by 8% in vegetables and 6% in corn. In contrast, earthworm activity enhanced MAOC, DOC, soil electrical conductivity (EC), and microbial community ratios (G+/G- and F/B), but also mobilized soil Cd, increasing total Cd accumulation by 15% in vegetables and 8% in corn under the combined treatment system. Random forest analysis identified crop biomass and the POC/MAOC ratio as the primary drivers of Cd uptake. Pearson correlation analysis further demonstrated that POC negatively correlated with Cd uptake, whereas MAOC positively influenced crop Cd accumulation. Overall, this study provides important insights into how the co-application of earthworms and biochar influences soil organic C storage and Cd dynamics in agricultural systems. While the combined strategy may improve soil C sequestration, caution is warranted because it may simultaneously compromise Cd stabilization, thereby increasing Cd bioavailability and accumulation in crops.

13. 题目: Chitosan-crosslinked microwave-engineered biochar alleviates lead stress in Brassica napus by improving soil functioning and plant performance in Pb-contaminated soil.
文章编号: N26071707
期刊: Journal of Environmental Management
作者: Fakhir Hannan, Yiwa Hu, Ahsan Ayyaz, Muhammad Iqbal, Muhammad Umair Yasin, Iram Batool, Juanjuan Li, Faisal Islam, Yasir Hamid, Muhammad Ahsan Farooq, Weijun Zhou
更新时间: 2026-07-17
摘要: Lead (Pb) contamination in agricultural soils reduces crop productivity and threatens food safety, highlighting the need for in situ amendments that lower Pb bioavailability while supporting soil functioning and plant performance. This study upgraded poultry manure-derived biochar through microwave activation and genipin-crosslinked chitosan modification (MPBCH), then evaluated its performance in a greenhouse pot experiment with Brassica napus grown in field-collected Pb-contaminated soil. Six treatments were compared: untreated Pb-stressed soil (CK), chitosan (CH), poultry manure biochar (PBC), microwave-prepared biochar (MPBC), chitosan-modified PBC (PBCH), and MPBCH. The MPBCH produced the strongest overall response, increasing soil pH from 5.84 to 6.95 and reducing DTPA-extractable Pb by 62.0%. Root and shoot Pb concentrations decreased by 52.1% and 57.9%, respectively, while immobilization-related indices consistently indicated lower Pb mobility and restricted soil-to-plant transfer. MPBCH also increased β-glucosidase, phosphomonoesterase, catalase, and urease activities by 43.74%, 40.22%, 60.24%, and 40.48%, respectively. Rhizosphere bacterial analysis showed the highest Shannon diversity (4.52) and Chao richness (1882.12) under MPBCH, with clear community separation in principal coordinates analysis, significant divergence by PERMANOVA (F = 3.73, R2 = 0.599, p = 0.0005), and enrichment of bacterial biomarkers. These belowground responses coincided with improved biomass, photosynthetic pigments, gas-exchange traits, nutrient status, antioxidant defense, and lower oxidative stress markers. Transcriptomic and qRT-PCR analyses supported reduced Pb-stress status under MPBCH, with shifts in carbon metabolism, glutathione metabolism, photosynthesis, and metal transport-related genes. Multivariate integration identified MPBCH as the strongest-performing treatment across the measured Pb immobilization, plant physiological, and soil biochemical responses.

14. 题目: Nitrogen Availability Modulates Root-Mediated Soil Organic Carbon Formation.
文章编号: N26071706
期刊: Environmental Science & Technology
作者: Xiaodong Wang, Lei Wang, Yarui Xin, Ying Zhang
更新时间: 2026-07-17
摘要: Living roots influence the formation of soil organic carbon (SOC) under straw incorporation, but the mechanisms underlying this process remain unclear. To elucidate these effects, we traced the fate of isotopically labeled maize straw into SOC via soil cores that were incubated in a soybean field. Our findings suggest that root ingrowth does not significantly affect the total SOC accumulation under straw incorporation but instead facilitates the allocation of SOC into stable SOC pools. However, the formation of stable SOC differs fundamentally between low-nitrogen (LN) and high-nitrogen (HN) soils. In LN soils, root ingrowth promotes the accumulation of stable SOC by promoting the transfer of straw-derived carbon into occluded particulate organic carbon (oPOC) and mineral-associated organic carbon (MAOC). In contrast, root ingrowth reduces the contribution of straw-derived C to stable SOC in HN soils, but this reduction may be offset by the incorporation of rhizodeposited C into oPOC and MAOC. Further research indicates that these different patterns are driven by a stoichiometric imbalance between the microbial demand for carbon and nitrogen and their resource availability. These findings provide mechanistic insights into how the presence of roots under straw incorporation influences SOC formation, deepening our understanding of root-mediated SOC sequestration.

15. 题目: From Naturally Occurring to Engineered Nano-Biochar: Properties, Feasibility, and Challenges for Sustainable Environmental Remediation.
文章编号: N26071705
期刊: Environmental Science & Technology
作者: Dongbo Wang, Junyi Lin, Juexuan Tang, Yukui Fu, Xuran Liu, Wei Wei, Bing-Jie Ni
更新时间: 2026-07-17
摘要: Nano-biochar, present both as naturally occurring pyrogenic carbon and as an engineered product of controlled pyrolysis, with particle sizes typically ranging from a few to several hundred nanometers, exhibits up to 97-fold greater specific surface area, 20-fold higher maximum adsorption capacity for methylene blue, and enriched oxygen-containing surface functional groups (e.g., ─OH, ─COOH, ─C═O) relative to bulk biochar, emerging as a promising nanomaterial for environmental remediation. Despite growing research interest, existing reviews have focused predominantly on its beneficial properties, leaving toxicity, recoverability, and scalability insufficiently addressed, which limits the translation of nanoscale properties into engineering practice. To bridge this gap, this review critically synthesizes current knowledge on nano-biochar from an engineering application perspective, covering its properties, remediation benefits, technical feasibility, and integration with advanced technologies including artificial intelligence, membrane reactors, advanced oxidation processes, and 3D printing. Application risks and safeguard strategies are critically assessed, alongside a conceptual sustainable paradigm to connect nanoscale material performance with real-world deployment. Future studies are suggested to prioritize reliable detection techniques, improved recovery or detoxification strategies, and low-input, high-efficiency technologies within a One Health framework to ensure safe deployment.

16. 题目: Investigation of Adsorption Mechanisms in Competitive and Non-Competitive Systems: Cadmium Immobilization in Contaminated Calcareous Soil Amended with Bone-Derived Biochar
文章编号: N26071704
期刊: Water, Air, & Soil Pollution
作者: Sobhan Mohamadi, Ghasem Rahimi, Abolfazl Khademi-Jolgeh Nezhad, M Mirari Antxustegi, María Gonzalez-Alriols
更新时间: 2026-07-17
摘要: Biochar (BC) has emerged as a promising soil amendment for reducing the bioavailability and toxicity of heavy metals such as cadmium (Cd) in contaminated soils. This study investigates the effectiveness of cow bone-derived biochar (CBBC), produced by pyrolysis at 550 °C, and ZnCl₂-activated biochar (A-CBBC) for Cd immobilisation in calcareous soils. Comprehensive characterisation of CBBC and raw bone powder (BP) was performed using elemental analysis, X-ray fluorescence (XRF), Brunauer–Emmett–Teller (BET) surface area analysis, scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) spectroscopy. Cadmium mobility was assessed through sequential fractionation and adsorption isotherm experiments under both competitive and non-competitive conditions. The results showed a reduction of approximately 10% in the exchangeable Cd fraction and the mobility factor (MF) in soils amended with 5–7% CBBC after six months of incubation. Adsorption isotherms indicated that soluble Cd concentrations were approximately twice as high under competitive conditions than under non-competitive conditions. Cadmium concentrations in untreated soils were 2.7-fold higher than those in soils amended with CBBC and BP. Relative to the control, CBBC and BP increased Cd adsorption by approximately 300 and 140 µmol kg⁻1, respectively. The observed reductions in Cd mobility are consistent with enhanced sorption associated with cation exchange and surface complexation, although these mechanisms are inferred from adsorption behaviour and fractionation data, not directly verified by spectroscopic analysis. Overall, the findings highlight the potential of CBBC and BP as effective amendments for reducing Cd mobility in calcareous soils and support their application as sustainable remediation strategies for heavy-metal-contaminated alkaline environments.

17. 题目: Microbial mechanisms of carbon turnover in humic acid-amended paddy soils
文章编号: N26071703
期刊: Journal of Soils and Sediments
作者: Shuwei Sun, Xiaoxue Zhang, Shuigang Wen, Senpei Lin, Minghao He, Lihua Zhou, Yong Yuan
更新时间: 2026-07-17
摘要: Purpose Humic acids (HAs) are widely recognized as soil amendments that improve soil quality, but their specific influence on carbon turnover dynamics in soils has yet to be fully elucidated. This study investigated how different types of HAs regulate the transformation pathways of soil organic carbon components and their underlying microbial control mechanisms. Materials and methods Neutral (Guangdong) and acidic (Jiangxi) paddy soils were spiked with three HAs—synthetic (straw-derived, SHA), peat-derived (PHA), and compost-derived (cattle manure, CHA)—at 5 g/kg. Under 30-day anaerobic incubation, CH4 and CO2 emissions, soil organic carbon (SOC), environmental parameters, and microbial communities were monitored. Results and discussion In neutral and acidic soils, SHA significantly increased CH4 production by 68.32-fold (from 0.13 to 8.8 µmol/g) and 23.3%, respectively. It also significantly elevated SOC by 21.82% and 20.39%. In contrast, PHA and CHA exerted lesser effects on carbon turnover. Microbial analysis revealed that SHA significantly altered microbial community structure and carbon metabolic functions, with promoted acetate-type and hydrogen-dependent methanogenesis. Moreover, SHA stimulated the DC/4-HB pathway but inhibited rTCA and WL pathways, whereas PHA and CHA exhibited opposite trends. Correlation indicated that structure-dependent effect of HAs on microbial carbon turnover. SHA, with its high aliphatic content, was the most effective driver of carbon transformation and methane emissions, surpassing the aromatic macromolecules PHA and CHA. Conclusion These findings indicate that HAs’ chemical complexity drives short-term microbial carbon turnover. However, given the substantial CH₄ emissions induced by SHA, long-term assessments are essential before recommending specific HA amendments for soil carbon sequestration.

18. 题目: Combined effect of biochar and seed priming on soil fertility and physio-biochemical traits of sweet corn (Zea mays L.) seedlings under drought stress
文章编号: N26071702
期刊: Plant and Soil
作者: Salih Demirkaya, Güney Akınoğlu, Elif Öztürk Ay, Nursaç Serda Kaya, Ömer Taş, Abdurrahman Ay, Gürkan Bilir, Deniz Ekinci, Coşkun Gülser
更新时间: 2026-07-17
摘要: Aims This study evaluates the combined effects of biochar and seed priming on soil properties and physio-biochemical responses of sweet corn seedlings under different drought conditions. Methods Three irrigation regimes were used to simulate drought stress: 100%, 75%, and 50% field capacity. Seeds were hydroprimed (HP) with distilled water, primed with 100 µM melatonin (MP), or control, and sown in pots with or without rice husk biochar (1%, w/w). Plant growth attributes and soil fertility were assessed. Results Drought stress significantly suppressed growth attributes. Compared with FC100, FC50 reduced fresh and dry biomass by 17.1% and 18.4%, respectively, while WUE decreased from 1.22 to 1.05 g mm⁻1. Among the priming treatments, HP produced the highest dry biomass (5.09 g pot⁻1), whereas MP resulted in the lowest (4.06 g pot⁻1). Biochar application consistently improved RWC and WUE, with the MP with biochar application achieving the highest WUE (1.18 g mm⁻1). Drought altered nutrient dynamics by increasing shoot Ca and Mg and root N and K, while reducing soil available P. Oxidative damage, indicated by elevated MDA, intensified under drought, accompanied by increased antioxidant enzyme activities. Biochar amendments significantly reduced MDA and moderated antioxidant responses. Soil organic carbon (0.69–0.88%) and exchangeable K remained higher in biochar-amended pots across all drought levels. Conclusions The combined application of rice husk biochar and seed priming effectively mitigated drought stress by improving soil properties, enhancing plant water relations, and moderating physiological and biochemical stress responses. This synergy supports healthier seedling development and improved drought resilience in sweet corn.

19. 题目: How C: N imbalance regulates biochar priming: response of main microbial groups in soils with contrasting fertility
文章编号: N26071701
期刊: Biology and Fertility of Soils
作者: Weiwei Lu, Yanan Wang, Huili Geng, Honghua Ruan
更新时间: 2026-07-17
摘要: Priming effect (PE) of exogenous organic matter on native soil organic carbon (SOC) is a key driver of soil carbon (C) dynamics. However, how biochar regulates PE and microbial mechanisms remains unclear, limiting accurate assessment of soil C sequestration. We conducted a 360-day incubation experiment with 13C labeling to investigate PE dynamics and underlying microbial mechanisms induced by two types of 500 °C biochar (rice straw (RB500) and poplar twig (PB500)) in two contrasting soils: high-fertility (SH) and low-fertility (DT). Six treatments were included: S-CK, S-RB500, S-PB500, D-CK, D-RB500 and D-PB500. Initial negative PE was observed in all biochar-amended soils. Positive PE occurred mainly at the mid-incubation (~ 60–120 d) in SH soil and at the late incubation (> 180 d) in DT soil. Furthermore, PB500 induced an earlier transition from negative to positive PE than RB500 in both soils. In SH soil, compared with the early and late incubation stages, S-PB500 exhibited the highest C: N imbalance (4.43) and specific activities of N-acetyl-β-D-glucosaminidase and leucine aminopeptidase (0.20 and 4.89 µmol g C− 1 h− 1, respectively) at the mid-incubation stage, and these patterns were more consistent with “microbial N mining” In contrast, both D-RB500 and D-PB500 in the DT soil showed the lowest C: N imbalance (0.24–0.45) and the highest microbial biomass C during the late incubation stage, matching the patterns of “microbial stoichiometric decomposition”. This study proposes potential mechanisms for biochar-induced positive PE in contrasting forest soils and offers new insights into biochar use and soil C sequestration.

20. 题目: Total copper explains variation in soil organic carbon accumulation but not in situ soil respiration: An ecosystem evaluation of a century-old wood impregnation site.
文章编号: N26071308
期刊: Environmental Toxicology and Chemistry
作者: Ingrid Rijk, Michaela Zeiner, Dan B Kleja, Linee Goswami, Alf Ekblad
更新时间: 2026-07-13
摘要: Soils have become prominent and long-term sinks for contaminants, which leads to concerns about disruption of microbially driven processes in the soil carbon (C) and nitrogen (N) cycles. This field study used a 100-year-old copper (Cu) gradient (50-2,300 mg kg-1 dry wt) in a previous wood impregnation site to evaluate impacts on soil physicochemical properties, microbial functionality, and vegetation aided by stable isotopic approaches. At 0-5 cm depth, Cu had no effect on microbial biomass and activity (in situ substrate-induced respiration; C4-SIR). At 5-10 cm depth, microbial biomass decreased and soil organic C (SOC) and N increased in areas of high Cu. Subtle changes in soil and leaf δ13C and δ15N marked the site, with 1‰ depletion of δ15N, and 0.5‰-2‰ increase of δ13C with higher Cu. To identify predictors of SOC variation and soil respiration, multivariate modeling with partial least squares regression (PLSR) was applied. The PLSR indicated that total Cu positively correlated with higher SOC content across all soil layers, explaining 32% variance at 0-5 cm depth, 67% at 5-10 cm, and 11% at 10-15 cm. At 0-5 cm depth, moss coverage, δ15N, fine root biomass, and in situ basal respiration and C4-SIR rates influenced the final PLSR model (64% variance explained). At 5-10 cm depth, δ13C was another strong predictor of SOC. The PLSR showed that Cu could not directly explain variation of soil respiration rates, whereas SOC stock, root biomass, microbial biomass N, and δ15N seemed more important predictors. The results indicate a current acclimated microbial community in upper soil, but prevailing impacts in lower layers. Soil Cu contamination has left an imprint in the area in the form of SOC accumulation and subtle stable isotopic gradients, which could serve as integrative markers of C and N cycling in disturbed ecosystems.