Environmental and Earth Sciences

Abstract: Corporate carbon offsetting schemes heavily rely on tree planting for carbon sequestration, and in Scotland the government presents tree planting as a key carbon sink in the face of climate change. However, carbon offsetting schemes rarely consider associated fluxes in soil organic carbon (SOC) driven by afforestation. Soils in woodlands store approximately 75% of the total ecosystem carbon, yet planting trees on existing carbon-rich soils or grassland may result in changes in soil carbon that take decades for tree biomass to recover. This study provides a methodological framework using the chronosequence approach (space-for-time substitution) to measure whole-ecosystem carbon storage for existing commercial carbon sequestration schemes. A proof-of-concept pilot study was carried out at the University of Edinburgh’s Rullion Green site, gathering 35 soil samples across unplanted baselines, a recent 2025 planting scheme, and a mature mixed woodland. The findings of this proof-of-concept study show that soil carbon in the newly planted area (5.06% SOC) was lower than in the mature woodland (7.64% SOC) and remained statistically similar to the unplanted baseline (7.11-8.65% SOC depending on slope). The carbon in the recently planted trees (4.10 t C/ha) did not offset the carbon losses from soil, with a drop in ecosystem carbon of 156.41 t C/ha compared to the baseline, and 418.23 t C/ha compared to the mature woodland. The methodology and trial study suggest that initial tree planting may not guarantee an immediate net increase in ecosystem carbon until trees become mature. The methodology therefore provides a tool to help mitigate greenwashing in the offsetting industry. The methodology will now be applied in further research to other sites across northern England to determine what the impact of tree planting for carbon sequestration is on soil in the UK.

Abstract: Afforestation is widely used to restore degraded Mediterranean landscapes, yet restoration success is often evaluated using vegetation establishment or soil carbon accumulation, with less attention to belowground ecosystem functioning. We assessed whether Cedrus libani afforestation promotes soil functional recovery in degraded Mediterranean karst and whether structural and microbial indicators provide robust measures of restoration progress under edaphic heterogeneity. Topsoil (0–10 cm) was sampled from degraded non-afforested reference land and 10-, 15-, and 25-year-old plantations in southern Türkiye. Soil organic carbon (SOC), total nitrogen (TN), aggregate stability, microbial biomass carbon (MBC), basal respiration, microbial quotient (qMic), and metabolic quotient (qCO₂) were determined. Afforested soils had higher SOC (1.55% vs. 2.37–3.35%), TN (0.053% vs. 0.087–0.190%), aggregate stability (61.3% vs. 77.8–84.9%), and MBC (180 vs. 288–536 µg g⁻¹), whereas basal respiration declined from 0.96 to 0.30–0.36 µg CO₂–C g⁻¹ h⁻¹ and qCO₂ from 5.41 to 0.54–1.39. qMic did not differ significantly among chronosequence classes. MBC was strongly associated with SOC (ρ = 0.917, P < 0.001) but not with basal respiration (ρ = −0.075, P = 0.57). Sensitivity analyses accounting for carbonate content and pH showed that aggregate stability, basal respiration, and qCO₂ were comparatively robust, whereas SOC, TN, and MBC responses were partly substrate-dependent. Multivariate analyses revealed coordinated but non-monotonic shifts across the chronosequence. These findings indicate that restoration outcomes in Mediterranean karst cannot be assessed from carbon accumulation alone and that integrating microbial metabolic and structural indicators with edaphic information provides a more informative framework for monitoring afforestation success.

Abstract: Increasing soil contamination by potentially toxic elements (PTEs) threatens environmental quality and ecosystem health, reinforcing the need for effective remediation strategies. Phytoremediation uses plants to remove, immobilize, or neutralize contaminants and represents a sustainable approach for restoring contaminated soils. Although nickel (Ni) is an essential plant micronutrient, elevated concentrations can cause phytotoxicity. This review synthesized data from field and controlled-condition studies on the effects of soil Ni concentrations and the phytoremediation performance of plant species. A Web of Science search identified 230 studies, of which 94 met the predefined inclusion criteria. Plant responses varied according to species and Ni concentration. More than 86% of the 449 plant records corresponded to herbaceous plants; Poaceae accounted for over 26% of the reported Ni-phytoremediating taxa, followed by Brassicaceae at approximately 18%. Brassica juncea showed the most consistent performance, combining Ni tolerance with phytoextraction and hyperaccumulation. Alyssum murale exhibited the highest phytoextraction capacity and the highest Ni concentration among the hyperaccumulators. Overall, the reviewed evidence supports phytoremediation as a sustainable strategy for Ni-contaminated environments. However, further research is required to support large-scale implementation and ensure alignment with global environmental sustainability objectives.

Abstract: Next-generation sequencing (NGS) has transformed soil microbial ecology by revealing taxonomic and functional diversity that was largely inaccessible through cultivation-based approaches. However, greater sequencing resolution alone does not explain why particular microbial assemblages repeatedly emerge under specific soil and environmental conditions. This review examines the current state of NGS-based soil microbiome characterization and introduces Hierarchical Environmental Filtering (HEF) as a framework for interpreting microbial community assembly. We discuss advances from amplicon sequencing to shotgun metagenomics, long-read sequencing, multi-omics, and computational analysis, together with limitations related to sampling, DNA extraction, primer selection, sequencing depth, bioinformatics, reference databases, and relic DNA. Within HEF, pedogenesis establishes the physicochemical template for microbial assembly, while climate, vegetation, rhizosphere processes, and biological interactions act as secondary filters. Anthropogenic disturbances may modify or partially override these natural filters, promoting community reassembly and ecological convergence. Soil microbiomes should therefore be interpreted as dynamic outcomes of environmental selection across spatial and temporal scales. Integrating standardized NGS workflows with functional multi-omics and predictive computation should advance soil microbiome research from descriptive inventories toward a mechanistic understanding of community assembly.

Abstract: Climate change poses one of the greatest threats to the sustainability of rainfed agriculture in Latin America, where common bean (Phaseolus vulgaris L.) production is particularly vulnerable because of its high sensitivity to fluctuations in temperature and precipitation, as well as to extreme climatic events. This scoping review aimed to examine the evolution of scientific research on the impacts of climate change on the sustainability of rainfed common bean production in Latin America by identifying geographic and temporal research trends, methodological approaches, major scientific advances, knowledge gaps, and future research priorities. The review followed the Joanna Briggs Institute (JBI) methodological framework and the PRISMA-ScR reporting guidelines and included 154 peer-reviewed studies published in indexed journals. The evidence was synthesized by country, publication period, and methodological approach, encompassing field experiments, agroclimatic assessments, crop-simulation models, Geographic Information Systems (GIS), remote sensing, review articles, meta-analyses, and farmer surveys. The results revealed that scientific production was concentrated primarily in Mexico and Brazil, whereas research in the remaining Latin American countries remained limited and geographically fragmented. Over time, the field evolved from studies focused primarily on crop physiology and genetic improvement toward multidisciplinary approaches integrating climatic, agronomic, environmental, and socioeconomic perspectives. Despite these advances, important knowledge gaps remain, particularly the limited availability of long-term field experiments and the insufficient integration of environmental, economic, and social dimensions into climate adaptation research. This review provides a comprehensive regional synthesis of the available scientific evidence on climate change and rainfed common bean production in Latin America, offering a solid evidence base to guide future research, inform climate adaptation strategies, and strengthen the resilience and sustainability of rainfed common bean production systems.

Abstract: Unavailability of inexpensive, reliable and smart health monitoring system for the soil and growing agricultural crop in developing countries like India is the major constraint for economic productivity and self-sufficiency in agro-products. To address such a burning issue, the present paper proposes an IoT based solar powered, inexpensive smart sensory system, for in situ and ex situ health monitoring of agricultural soil and growing crops. Here, the proposed system uses a single sensing mechanism to monitor the nitrate concentration in the roots of the crop as well as pH of soil. Additionally, the system has been integrated to measure all the ambient parameters detrimental to plant and soil health. The features including auto compensation of the measured parameters against temperature and humidity variations, auto calibration of the sensory systems adds smartness to the device. All the measurands were compared with the respective standard instruments and for all the measurements, readings were highly correlated with R2-value ranging from 0.98 to 0.99.The performance of the device was checked in the field and the results obtained were very satisfactory.

Abstract: Long-term field trials are important for evaluating the environmental and economic sustainability of crop and soil management practices. The current study evaluated differences in soil organic carbon (SOC), total nitrogen (N), extractable phosphorus (P) and pH across tillage and straw management systems of dryland wheat monocrop after approximately 40 years (1979 - 2018) of experimentation on an acric plinthosol. The study also determined the effects of tillage, straw management and N fertiliser rate on wheat grain yield after every 10 years over 40 years. Treatments consisted of plots under conventional tillage (CT), stubble mulch (SM) and no-tillage (NT), combined with either straw burning (burned) or retention (not burned). Nitrogen fertiliser rates tested were 20, 40 and 60 kg N ha^-1. Straw burning (p < 0.05) increased soil pH significantly and Bray-1 extractable P under NT, but not in other tillage systems. The Bray-1 extractable P declined down the profile, regardless of tillage or straw management. Total soil N was higher under NT than other tillage practices but did not vary with straw management, while SOC was not significantly affected by tillage or straw management. Wheat grain yield was significantly increased by higher N fertiliser levels and wetter seasons over the years. The findings suggest that after 40 years of practice, the main driving factors for wheat yield in the low-input dryland monocropping system, under semi-arid conditions, are N fertiliser and seasonal rainfall; hence, farmers may benefit by considering supplementary irrigation during drier years. Furthermore, no-till could be beneficial to improve total N. When combined with straw burning, it also increases soil pH and P, but an alternative strategy for sustainable SOC build-up needs to be sought for this soil type under semi-arid conditions.

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The increasing demand for food production has intensified the use of chemical fertilizers, raising concerns about their environmental impact. Plant Growth-Promoting Bacteria (PGPB) have emerged as a sustainable alternative; however, many studies are conducted under highly controlled conditions which do not accurately represent real agricultural systems. This study evaluated the effect of microbial consortia comprising of Azospirillum brasilense, Pseudomonas putida, Bacillus sp., and Mycobacterium sp. on plant growth under contrasting substrate conditions (commercial substrate and greenhouse soil). Their biostimulant potential was assessed in Zea mays (blue maize), Brassica oleracea (broccoli), and Solanum lycopersicum (tomato). The assessment included measurements of root and shoot elongation as well as dry biomass. The results demonstrated that microbial consortia significantly (p=0.01) improved plant growth compared to the control across all species. Among the treatments, the consortium Pseudomonas putida + Bacillus sp. had the best results by presenting significantly (p=0.01) higher values in root length, stem growth, and dry weight in both substrate types. Additionally, consortia containing Mycobacterium sp. demonstrated enhanced performance in greenhouse soil, particularly in biomass accumulation for Zea mays and Brassica oleracea. These results highlight the importance of selecting appropriate microbial combinations and validating their performance in environments that reflect practical agricultural conditions.

Abstract: The expansion of anaerobic digestion has created two linked opportunities: renewable-energy production and the return of nutrients and organic matter to land. It has also created an agronomic problem that cannot be solved by calling every residual material a biofertilizer. Digestate varies with feedstock, digestion conditions, separation, storage, post-treatment and the point at which it is sampled. Its value therefore emerges only when product composition is connected to crop demand, soil conditions, application practice and the environmental pathways that remain open after land application. This structured critical narrative review brings together evidence on crop production, nutrient replacement, soil physical and biological responses, greenhouse-gas emissions, nutrient losses, contaminants, processing and practical implementation. Greatest interpretive weight is given to inspectable original studies and replicated field evidence; reviews and meta-analyses are used to identify consistency and heterogeneity, not counted as additional experiments.The major points are the following. First, whole and processed digestates can replace part of a mineral-fertilizer programme, but the replacement value belongs to the complete product-management-soil-crop system rather than to digestate as a universal material. Trials that appear to compare equal fertilizer rates often match different quantities of total N, ammonium-N, estimated available N, P, K, S, organic N and carbon, and they frequently differ in mineral-fertilizer formulation, application timing and placement. Yield equivalence is therefore not automatically nutrient equivalence. Second, the product fraction matters. Liquid fractions commonly act as rapid N and K sources, whereas separated solids retain more particulate carbon and phosphorus and may release N more slowly. Third, long-term soil responses are real but conditional. Multi-year studies range from little detectable difference relative to slurry or mineral fertilizer to increases in soil-carbon pools under particular combinations of product, soil, crop, dose and management. Concentration changes, short incubations and degraded-soil demonstrations should not be treated as universal proof of durable stock change.Fourth, environmental performance cannot be represented by one emission factor or one safety label. Ammonia loss depends on pH, total ammoniacal N, dry matter, viscosity, storage, weather and surface exposure; nitrous oxide depends strongly on soil moisture, native mineral N, degradable carbon, placement and management history. Practices that reduce one pathway can increase another. Anaerobic digestion does not destroy metals, and evidence on pharmaceuticals, PFAS precursors, microplastics, phytotoxicity and antimicrobial resistance shows alteration of concentration, partitioning, viability or exposure rather than guaranteed removal. The central conclusion is consequently practical rather than promotional: digestate can be a valuable nutrient and, in some products and settings, carbon resource when it is characterized, matched to crop and soil requirements, applied with control of loss pathways and monitored over an appropriate timescale. It is neither intrinsically safe nor uniformly effective, but neither should it be dismissed as a waste when evidence-based management can recover useful functions.

Abstract: The rice-wheat cropping system under Vertisol in sub-tropical regions of India faces significant challenges in maintaining soil health and achieving sustainable yields. This is primarily due to climatic variability and intensive agricultural practices, which accelerate the loss of soil organic carbon (SOC) and lead to soil degradation. There is a pressing need to adopt sustainable nutrient management, that not only maximize crop yields but also support climate change mitigation through carbon (C) sequestration and soil health management. In this context, a long-term fertilizer management (25 years) study was undertaken to assess crop productivity, C fractions, sequestration potential to achieve soil C 4 per mille under rice-wheat cropping system in sub-tropical Vertisol. The experiment was based on ten different fertilizer treatments either alone or in combination with organics. Grain yield, system productivity, and the sustainable yield index (SYI) were significantly higher under the 150%NPK and NPK + Farmyard manure (FYM) treatments compared to the unfertilized control. Relying on imbalanced fertilization (N) is inadequate for long-term sustainability. Long-term application of 100% NPK+FYM increased SOC content by up to 16%, whereas it decreased by 34% under absolute control relative to the initial value. Integrated nutrient management (INM) significantly enhanced the SOC pools, with higher proportion (57%) of total SOC in passive C pools. The increase in SOC stock was significantly correlated (R² = 0.76) with system productivity, requiring a minimum C input of 2.7 Mg C ha^-1 yr^-1 to maintain C equilibrium. The INM treatment achieved the highest C sequestration (2.27 Mg ha^-1), potential (7.04 Mg ha^-1) and rate (0.10 Mg C ha^-1 yr^-1) compared to NPK. In the present study, the C sequestration rate under NPK+FYM and 150%NPK surpassed the annual increment requirement of 0.4% SOC to achieve the target of the “4 per mille”. Over 25 years, application of 5 Mg ha^-1 FYM with NPK proved to be the most sustainable practice for SOC management. In addition to enhancing SOC stock, this practice maximizes crop productivity, thereby highlighting the potential of soil management as an effective voluntary carbon sequestration pathway for climate-change mitigation strategy in sub-tropical regions.

Abstract: Abandoned paddy wetlands (APWs), which are converted from rice paddy wetlands (RPWs) due to natural or artificial cessation of farming, function as crucial carbon sinks. Although APWs serve as vital cultural and ecological resources providing essential ecosystem services, these excellent ecosystems are often inadequately managed, leading to rapid degradation and transformation into carbon emission sources. This study was conducted to quantify the carbon accumulation capacity of reference APWs distributed across the central region of the Republic of Korea. In accordance with the Intergovernmental Panel on Climate Change (IPCC) Good Practice Guidance for Land Use, Land-Use Change and Forestry (GPG-LULUCF), soil samples were collected from each APW at a depth of at least 30 cm. Subsequently, soil organic matter (OM) content, soil organic carbon (SOC; g/kg), and soil organic carbon storage per unit area (SOCS; kg/m²) were calculated. Additionally, carbon absorption based on land cover was measured within the hydro-ecological impact zone (a 300-m buffer zone) surrounding the APWs, and carbon accumulation via the biomass of dominant vegetation was evaluated. For APWs dominated by woody plants, carbon storage was determined by tree height, diameter at breast height (DBH), and population size, whereas population coverage size determined carbon storage in wetlands dominated by herbaceous plants or mixed woody-herbaceous communities. The results revealed that the average OM of the APWs was 33.7 g/kg, and the SOC per unit weight was 19.54 g/kg. The accumulated SOCS per unit area was mathematically corrected from 67.97〖" kg/m" 〗^2 to 61.20±22.28〖" kg/m" 〗^2, which is approximately 8.5 to 40 times higher than the average SOCS of forest soils in South Korea (7.19 kg/m² in Jeju Island) and urban parks (1.56 to 2.84 kg/m²). Furthermore, the average carbon absorption within the hydro-ecological impact zone increased rapidly over time, rising from 20.45 tCO₂/ha in 2000 to 35.30 tCO₂/ha in 2013, and reaching 38.14 tCO₂/ha in 2021.

Abstract: The biological nitrogen fixation of black locust (Robinia pseudoacacia L.) is an important factor that allows the trees to survive under adverse environmental and nutrient-poor soil conditions. Due to the open-cast mining activities, large areas in the Lusatian region in eastern Germany were left unproductive with a very nutrient-poor soil with a low amount of nitrogen (N), phosphorous (P) and no organic matter. The symbiotic N₂ fixation of Robinia pseudoacacia L. has been investigated using the natural ¹⁵N abundance method. Moreover, the C:N:P ratio of soil and plants was determined. In addition, the impact of low soil P nutrition on nitrogen fixation was investigated. The N and P increased with the age of the tree plantation, but no relation was found between the carbon content and the age of the trees. Previous studies have seen an increase in soil N and P with the age of Robinia pseudoacacia L. The desorption of P was higher in the oldest plantation site, which is related to the plant availability of P. Results from the NdfA% show that about 98% and 88% of N were derived from the air by the plants planted in the reference zero site and the oldest plantation site, respectively. This slight difference in nitrogen fixation indicates that P has less impact on the nitrogen fixation of Robinia pseudoacacia L. Hence, more long-term research is required to examine the P uptake of plants from low P soil and how plants manage the biological N fixation with low soil P.

Abstract: Soil microorganisms are essential for nutrient cycling, plant productivity, and soil health, yet the relative importance of land use and soil depth in shaping agricultural microbiomes remains poorly understood. This study investigated soil microbial com-munities across uncultivated land, alfalfa fields, crop systems (feed corn and sweet corn), and orchard systems (walnut and quince) in the Hajdúnánás region of Hungary using shotgun metagenomic sequencing and soil physicochemical analyses. Microbial alpha diversity varied little among land-use systems but declined signifi-cantly with soil depth. Community composition was primarily structured by depth (R² = 0.233, p = 0.001), while land-use effects were stronger for fungal communities (p = 0.001) than for bacterial communities (p = 0.012). Crop soils contained the highest numbers of unique bacterial and fungal taxa. Functional analyses revealed significant differences in nutrient cycling, plant-growth-related, decomposition, and environ-mental adaptation functions among land-use systems. In crop soils, topsoil communi-ties were enriched in oxidative stress-related pathways involved in ROS detoxification, redox homeostasis, and stress regulation, whereas subsoil communities showed a greater representation of antioxidant metabolite production functions. Co-occurrence network analyses indicated greater connectivity in perennial systems, particularly al-falfa soils. Pathogen analyses identified stable bacterial and fungal pathogen cores across agricultural systems, with soil pH emerging as the strongest environmental factor associated with pathogen abundance. Overall, soil depth was the primary driver of microbial community assembly, whereas land use mainly influenced microbial composition, ecological functions, interaction networks, and pathogen distribution.

Abstract: Integrated organo-mineral fertilization is considered an effective strategy for im-proving soil quality, nutrient use efficiency, and productivity in acidic orchard systems. This study evaluated the effects of compost (30 t ha⁻¹ combined with P₁₅₀K₁₂₀) and nitrogen fertilizers (urea or ammonium nitrate applied at 0, 90, 120, and 150 kg ha⁻¹) on soil quality, nutrient dynamics, yield, fruit quality, and nu-trient use efficiency (NUE) of kiwifruit grown on acidic Luvisols in the humid subtropical Lankaran–Astara region of Azerbaijan during a two-year field ex-periment. Integrated fertilization significantly increased soil organic carbon (SOC), water-stable aggregates (WSA), and nutrient availability (NH₄⁺–N, NO₃⁻–N, P₂O₅, and K₂O) in both non-degraded and moderately degraded soils. Results showed strong positive relationships between soil organic carbon (SOC) and soil fertility parameters, particularly NH₄⁺–N (R² = 0.92), NO₃⁻–N (R² = 0.84), P₂O₅ (R² = 0.82), and water-stable aggregates (WSA; R² = 0.76), highlighting the crucial role of SOC in enhancing soil fertility, promoting nutrient availability, and improving soil structural stability. Stepwise regression analysis showed that NO₃⁻–N (~73%), P₂O₅, SOC, and K₂O together explained 93% of the variation in kiwifruit yield (R² = 0.93, P < 0.001). Fertilization significantly improved kiwifruit productivity and fruit quality. In non-degraded soil, yield increased from 7004 to 20,139 kg ha⁻¹ under Base + N150treatment; however, the increase over Base + N120 was small and non-significant. Urea generally resulted in higher yield, better fruit quality, and greater NUE than ammonium nitrate, particularly under non-degraded soil conditions. The highest NUE was observed under the urea N120 treatment (0.99), whereas NUE declined at higher nitrogen application rates. Integrated fertilization also reduced the productivity gap between degraded and non-degraded soils, demonstrating its restorative potential for degraded acidic Luvisols. The combi-nation of compost (30 t ha⁻¹) and a moderate nitrogen application rate (N120), particularly in urea form, represented the most effective strategy for improving soil fertility, enhancing kiwifruit yield and quality, increasing economic return, and reducing possible environmental risks under humid subtropical conditions.

Abstract: Desertification represents a critical environmental challenge in arid and semi-arid regions, driven by the synergistic impacts of climate change and unsustainable landuse practices. This review presents a comparative assessment of desertification dynamics, mitigation strategies, and ecological restoration approaches in the Ningxia Hui Autonomous Region (China) and Egypt. Both regions are characterized by severe water scarcity, increasing climatic variability, and fragile ecosystems; however, they differ in ecological conditions, institutional frameworks, and dominant land degradation processes. The study synthesizes major drivers of desertification, including rising temperatures, precipitation variability, recurrent droughts, soil salinization, overgrazing, wind erosion, and unsustainable agricultural expansion. It further evaluates key control measures implemented in both regions, such as afforestation and ecological engineering, sand dune stabilization, water-efficient irrigation systems, soil rehabilitation practices, and the integration of remote sensing and GIS-based monitoring technologies. The analysis highlights China’s large-scale, long-term ecological restoration programs, which have significantly improved vegetation cover and reduced land degradation, compared to Egypt’s focus on irrigation efficiency, land reclamation, and salinity management under extreme aridity constraints. The comparative synthesis demonstrates that effective desertification control requires integrated strategies combining ecological restoration, sustainable water resource management, technological innovation, and strong policy support. Despite contextual differences, both regions offer complementary lessons for dryland management. The study emphasizes the potential for enhanced China–Egypt cooperation in climate-smart agriculture, digital environmental monitoring, and nature-based solutions to advance sustainable land restoration under future climate change scenarios.

Abstract: We present a global metadata comprising results from studies investigating the effects of cover crops (CCs) on six key soil hydraulic properties, namely total porosity, infiltration rate, saturated hydraulic conductivity, water retention at field capacity and permanent wilting points, and available water holding capacity. This data repository is the result of a global meta-analysis entitled “Cover crop performance and functional groups regulate improvements in Soil Hydrology: A Global Meta-analysis". Globally, numerous studies have investigated the role of CCs on soil hydraulic properties, but the results have varied across sites and years. Hence, the objective of the meta-analysis was to synthesize existing knowledge base to assess overall effects of CCs on these soil hydraulic properties and evaluate how environmental and management factors moderate these overall CC responses. We searched for peer-reviewed research articles published through 5th October 2024 in the ISI Web of Science database and reference checking following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A total of 146 relevant articles were identified from which data on CC responses were extracted. The metadata consists of 1007 pairwise observations comparing CC vs no-CC controls across diverse geographic regions worldwide. Moreover, we collected associated metadata for each pairwise comparison that includes a broad set of bibliographic, geographic, soil, climate, and management variables. Categorical variables were grouped into pre-defined factor levels or classes. Missing soil and climate data were filled using publicly available data-products. Our data repository can be a valuable resource for the field and modeling community to identify knowledge gaps and guide future research.

Abstract: In the UK, contaminated land risk assessments using the Contaminated Land Exposure Assessment (CLEA) model rely on soil organic matter (SOM) values to determine acceptable thresholds for contamination caused by anthropogenic pollution for human health. Soil organic carbon (SOC), total organic carbon (TOC) or loss on ignition (LOI) are routinely used as a proxy for SOM in the industry, both by contaminated land consultants and laboratories who rely on conversions such as the Van Bemmelen factor. Many standard laboratory methods for measuring SOC or TOC do not differentiate between natural organic carbon and petroleum hydrocarbons. This study investigates the interference of total petroleum hydrocarbons (TPH) on SOC measurements by analysing 2,375 brownfield soil samples. A positive correlation was observed between the two variables; an addition of 1,000 mg/kg of TPH inflates reported SOC by 0.46 percentage points. When converted to SOM for risk assessment purposes using the Van Bemmelen factor, this artificial increase rises to 0.79 percentage points calculated SOM per 1000mg/kg TPH. This can push soils into higher assessment bands, generating less stringent Generic Assessment Criteria (GAC). The study finds that relying on SOC as a proxy for SOM in hydrocarbon-impacted soils masks the absence of the natural organic matter required to sorb contaminants, leading to an underestimation of human health risks in contaminated land risk assessments.

Abstract: Mangrove ecosystems are significant blue carbon sinks but can also act as sources of greenhouse gases, particularly carbon dioxide (CO₂) and methane (CH₄), due to complex sediment biogeochemical processes. This study quantified the influence of seasonal and tidal variability on soil–atmosphere CO₂ and CH₄ fluxes in mangrove ecosystems of the Lamu Archipelago, Kenya. Field measurements were conducted across wet and dry seasons and varying tidal heights, alongside key environmental parameters including temperature and humidity. Non-parametric statistical analyses revealed that CH₄ fluxes were significantly influenced by temperature variability (p < 0.05), whereas CO₂ fluxes were significantly associated with humidity (p < 0.05). Both gases exhibited significant seasonal variation (p < 0.05), with elevated CO₂ emissions during the dry season and higher CH₄ emissions during the wet season, reflecting shifts between aerobic and anaerobic sediment conditions. Tidal height exerted a significant effect on both CO₂ and CH₄ fluxes (p < 0.05), underscoring the role of tidal inundation in regulating redox dynamics and gas exchange processes. These findings demonstrate the strong coupling between climatic and meteorological parameters in controlling mangrove GHG fluxes and highlight the importance of incorporating temporal variability into blue carbon assessments. The study provides empirical data to refine greenhouse gas inventories and improve the representation of tropical coastal wetlands in climate models and mitigation frameworks.

Abstract: The cycling of greenhouse gases (GHGs) in soils is fundamentally regulated by molecular oxygen, and trees restructure the local O₂ landscape through root macropore networks, rhizosphere oxygen demand, and canopy-mediated moisture redistribution, generating spatially structured redox transitions that govern CO₂, N₂O, and CH₄ fluxes across distances of just a few meters from the stem. Despite this inherent spatial heterogeneity, most studies measuring soil GHG emissions in tree-based systems report fluxes from single locations without documenting distance from trees, effectively assuming spatial homogeneity where none exists. We introduce triproximity, a conceptual framework that considers tree–soil GHG interactions across three spatial dimensions: (i) horizontal distance from tree stems, (ii) vertical soil profile depth, and (iii) structural position relative to tree components, including the stem itself as a gas conduit. Following PRISMA guidelines, we systematically reviewed 107 field-based studies published between 2010 and 2025 spanning shelterbelts, agroforestry, orchards, silvopastoral systems, and riparian buffers across temperate, subtropical, and arid climates. Only 37.4% of studies explicitly reported measurement distance from trees, a proportion that has not improved despite a near four-fold increase in publication volume since 2020. Methane uptake showed the most consistent spatial response, with higher oxidation rates in the near-tree zone across diverse system types, most plausibly reflecting root-mediated improvements in soil aeration and methanotrophic activity. Nitrous oxide responses were context-dependent, governed by competing substrate availability and moisture controls that the triproximity dimensions help disentangle. Carbon dioxide fluxes showed no universal spatial pattern, yet were responsive to specific proximity dimensions once the dominant source term was identified. Stem-level gas transport was virtually unmeasured across the dataset, likely biasing ecosystem GHG budgets toward underestimation. We propose a minimum triproximity-based sampling protocol specifying horizontal distances, vertical depths, structural positions, and replicate requirements for five major tree-based system types, and call for journals to adopt spatial reporting as a minimum submission standard for GHG studies in tree-based agricultural systems.

Abstract: Fruit and vegetable wastes are important organic resources that can be recycled into value-added agricultural products through microbial fermentation. However, the characteristics of fermentation broths (FBs) derived from different fruit and vegetable substrates and their effects on soil ecological processes remain insufficiently understood. In this study, FBs were produced from 14 common fruit and vegetable wastes through anaerobic fermentation, whose characteristics were systematically analyzed in terms of nutrient composition, enzyme activities, and microbial community structure. Five representative FBs derived from garlic, tomato, sweet potato, apple, and lettuce were selected for pot experiments to evaluate their effects on soil properties and the growth of Brassica chinensis. The results showed significant differences among the FBs in nutrient contents, enzyme activities, and microbial community composition. The application of garlic FB exhibited the highest concentrations of ammonium nitrogen (309.81 mg/L), total phosphorus (327.73 mg/L), total potassium (1365.8 mg/L), and organic matter (28.99 g/L) in the pot soil, together with significantly higher activities of acid phosphatase, urease, protease, and catalase in the soil than the other treatments (P < 0.05). Metagenomic analysis revealed that the soil treated with garlic FB was dominated by lactic acid bacteria, with Lactiplantibacillus, Lentilactobacillus, and Levilactobacillus accounting for approximately 79% of the microbial community. The application of FBs significantly improved the availability of soil nutrients and the activities of enzymes. Among all the treatments, the application of garlic FB showed the strongest effects, increasing the activities of catalase, urease, acid phosphatase, and β-glucosidase in the soil by 83.34%, 180.72%, 112.34%, and 21.95%, respectively. Furthermore, the application of FBs reduced the incidence of pests and diseases, and promoted the growth of Brassica chinensis. Compared with the other treatments, the garlic FB treatment produced the highest vegetable biomass. It was concluded that the application of the FBs manufactured from fruit and vegetable wastes enhanced soil fertility and crop performance through the regulation of microbial communities, stimulation of soil enzyme activities, and promotion of nutrient cycling. For comparison, the application of Garlic FB exhibited the greatest potential as a sustainable biofertilizer for vegetable production and organic waste recycling.