Erosion affects soil health, nutrient cycling, and ecosystem productivity. Although the physical manifestations of erosion are well known, further research is needed to understand how its biochemical consequences interact to limit soil functionality and plant productivity. We investigated this in erosion-threatened chernozem soils of the Czech Republic using a pot experiment and a synthetic soil quality index (SQI) with Festuca rubra under varying nitrogen fertilization rates (0–250 kg N ha−1). Erosion significantly degraded soil biochemical quality, reducing soil organic carbon content from 1.40% to 0.78% (p < 0.001) and total nitrogen content from 0.15% to 0.13%. Microbial functions were severely disrupted, as evidenced by a 57% decrease in dehydrogenase activity (p < 0.001) and a 35% decrease in urease activity (p < 0.001). From a production perspective, erosion significantly reduced plant biomass (p = 0.004) across all treatment groups. While nitrogen fertilization significantly stimulated biomass production up to an intermediate rate of 50 kg N ha−1 (p < 0.001), higher application rates led to a strict yield plateau. These results demonstrate that erosion-induced deterioration of the soil’s biochemical complex acts as a primary constraint on crop growth, which cannot be compensated for by increasing doses of mineral nitrogen fertilizer.
Soil erosion is a critical global challenge and presents particularly alarming characteristics in the Amazon–Cerrado transition in Mato Grosso, a leading agricultural state in Brazil. Therefore, soil and water losses were evaluated under three soil cover conditions for corn and pasture cultivation (with vegetation cover, without vegetation cover, and without vegetation cover with soil scarified to a depth of 0.10 m) and four precipitation patterns (Advanced, Intermediate, Delayed, and Constant). The results showed that both soil cover and rainfall patterns directly influence the erosion processes. Soil loss increased up to sixfold under the Intermediate compared to the Constant rainfall, highlighting the strong influence of rainfall temporal distribution on erosion dynamics. The highest maximum runoff rates (MRR) and soil losses (SL) were recorded in tilled plots under maize cultivation, reaching 98.57 mm h−1 and 5.90 g m−2, respectively, under the intermediate pattern. In pasture areas, SL followed a similar pattern to the maize area, with maximum values of 6.96 g m−2, but the MRR was recorded under the advanced pattern and in plots with cover (89.71 mm h−1). This may be attributed to soil management conditions in pasture areas. Advanced and Intermediate patterns resulted in greater soil losses (3.78 and 2.04 g m2, respectively), highlighting the impact of peak intensity timing on soil erosion. Greater soil losses were observed at the pasture experimental site than at the maize experimental site. Because the experiments were conducted at different locations with contrasting soil and management conditions, these differences should not be interpreted as being caused exclusively by crop type. The current study reinforces the need for erosion control and management strategies that account for natural variations in rainfall and soil cover to mitigate the negative impacts of land degradation on agricultural production and environmental sustainability.
Magnetic-field-associated treatments have been investigated as possible modulators of microbial and plant–soil processes, but evidence for their effects on soil and rhizosphere bacterial communities remains fragmented and methodologically uneven. This review evaluates whether current literature provides credible evidence that magnetic-field-associated treatments affect bacterial communities in soil and rhizosphere-associated systems. The final review retained 65 publications, including 35 original studies in the qualitative evidence synthesis. The most mechanistically informative evidence comes from isolated bacterial strains and engineered microbial systems, where magnetic exposure has been associated with context-dependent changes in electron transfer, biofilm-related traits, oxidative-stress responses, nutrient-transformation processes and reactor performance. However, many community-level studies in engineered systems relied on single-reactor designs, duplicate reactors, endpoint-only sequencing or unclear sequencing replication, limiting their generalizability to soil ecosystems. Evidence from soil and coupled plant–soil systems is more directly relevant to agriculture but remains causally unresolved. Reported changes in bacterial-community composition, nutrient availability, enzyme activity and plant–soil conditions are best interpreted as system-level associations rather than as proof of direct magnetic-field effects on microorganisms. Material-mediated studies involving magnetic or Fe-containing amendments and observational studies from geomagnetic anomalies provide contextual information but cannot be used as direct evidence for magnetic-field effects. Overall, current evidence is preliminary and insufficient to support magnetic-field-associated treatments as practical tools for agricultural microbiome management. Future progress will require well-controlled experiments with sham controls, independent biological and exposure-unit replication, explicit exposure characterization, separation of plant-, soil-, and material-mediated pathways, and functional validation beyond taxonomic community shifts.
Heavy metal/loid (HM) pollution of soils, primarily as a consequence of mining and ore-processing activities, poses significant risks to ecosystems and human health. Soil microbial communities play essential roles in maintaining key ecosystem functions, including nutrient cycling, carbon sequestration, and soil stability. The purpose of this study was to characterize the taxonomic composition and diversity of bacterial communities and evaluate their functional adaptation to heavy metal stress in soils affected by long-term gold–copper mining activities in Bulgaria. Ten soil samples representing a Cu pollution gradient (53–860 mg kg−1) were categorized into five pollution classes. High-throughput sequencing of 16S rRNA gene amplicons revealed the dominance of the phyla Pseudomonadota (mean relative abundance 32%), Acidobacteriota (22%), and Actinomycetota (16%). At the class level, Alphaproteobacteria (18%), Terriglobia (16%), and Gammaproteobacteria (14%) were the most abundant taxa, indicating their adaptation to long-term heavy metal contamination. The genus Z2-YC6860 exhibited significant tolerance to Cu, whereas Bradyrhizobium_503372 was negatively associated with As and Zn concentrations. Functional predictions suggested enrichment of key pathways related to heavy metal resistance, including efflux systems and detoxification. The study design spans a broad Cu pollution gradient across river-associated and industrially impacted sites, providing an ecologically relevant framework for evaluating microbial responses to long-term metal stress.
This study addresses the need for reliable field-based tools to assess soil structural quality in semi-arid rangelands, where existing visual methods such as the Visual Evaluation of Soil Structure (VESS) and its modified version for grasslands (GrassVESS) may be limited by site conditions. The objective was to develop and evaluate a modified visual soil structure assessment method (RangelandVESS) adapted to livestock grazed rangelands in northern Mexico. Soil sampling was conducted in grazed and exclusion zones and soil structure was assessed using VESS, GrassVESS, and RangelandVESS. Thereafter, the scores of each method were compared with soil health indicators and above-ground biomass. Results showed distinctions in soil structural conditions between exclusion and overgrazed areas. RangelandVESS seems to demonstrate greater sensitivity to degradation, particularly in sandy soils, where it identified poorer structural quality compared to the other methods. Significant correlations were obtained between RangelandVESS scores and bulk density, infiltration, and biomass supporting its robustness. In contrast, no significant differences among methods scores were observed in clayey–loamy soils. However, RangelandVESS may provide a more reliable assessment of degradation. Overall, the findings suggest that RangelandVESS is a suitable tool for assessing soil structure in semi-arid rangelands and offers improved capacity to detect grazing induced degradation.
Heavy metal contamination in urban topsoil is one of the most serious environmental threats to children’s health, particularly through ingestion, dermal contact, and inhalation exposure routes. The objectives of this study were: (1) to assess the probabilistic exceedance-based priority of eight heavy metals (As, Cd, Co, Cr, Cu, Ni, Pb, and Zn) with respect to regulatory threshold exceedance in Debrecen, Hungary; (2) to map the spatial distribution of exceedance probabilities using sequential indicator simulation (SISIM) with 100 equiprobable realizations per element (1000 for Cr) on a 50 m grid; and (3) to develop a toxicologically weighted composite exceedance index based on the Hungarian regulatory action thresholds and classify the results into priority categories. For Cd, the exceedance probability exceeded p > 0.50 in approximately 98% of the study area, and for Cr, in approximately 82% of the study area (regenerated at N = 1000; the Cr threshold lies near the sample median, so the p > 0.50 area is ensemble-size sensitive and was under-converged at N = 100). Approximately 86% of the study area fell into the Very Low Priority class, approximately 14% into the Low Priority class, and less than 0.1% of the area exceeded the Moderate Priority threshold. Monte Carlo perturbation of the child exposure relevance factors confirmed strong spatial rank stability of H(x) (median Spearman ρ= 0.989), indicating that the priority pattern is robust even though areas close to the Very Low Priority/Low Priority boundary may change class. This paper contributes single-threshold exceedance-probability maps at regulatory limits and a toxicity-weighted exceedance-priority index H(x)—a methodological and interpretive advance over our previous concentration mapping, using the same measurements with no new sampling. By constructing the composite index is toxicity-weighted: arsenic and cadmium carry ≈88% of the child weight, so H(x) chiefly resolves As- and Cd-driven priority, with the remaining metals refining local class boundaries. Receptor prioritization is a screening output to guide confirmatory sampling, not a definitive risk classification.
Biological soil crusts (BSCs) are important components of dryland ecosystems, yet nutrient patterns in adjacent uncovered soils remain unclear. We surveyed 70 sites across the Gurbantunggut Desert and collected 209 composite samples from the adjacent 0–5 cm surface-soil layer, categorized into three groups: uncrusted bare sand (n = 32), soil adjacent to algal–lichen crusts (n = 48), and soil adjacent to moss crusts (n = 129), with bare sand serving as the uncrusted reference category. The results showed that: (1) total nitrogen differed among the three BSC-associated soil categories (p = 0.041), whereas soil organic carbon, total phosphorus, and total potassium did not (all p > 0.05); (2) NO3−-N, NH4+-N, extractable inorganic N, NaHCO3-extractable phosphorus, and NH4OAc-extractable potassium differed significantly among categories (all p < 0.001) and were generally highest in soil adjacent to moss crusts; and (3) random forest models explained approximately 38–65% of nutrient variation and identified EC, total nitrogen, and the site-level BSC metric as the leading predictors. The final piecewise structural equation model explained 35.3–76% of nutrient variation. These findings indicate marked regional heterogeneity in extractable nutrient fractions associated with different BSC types.
Soil–Forage–Livestock systems (SFL-systems) integration is fundamental for sustainable land management in arid lands, where conventional crop production is often unfeasible. Aridisols dominate dryland agroecosystems and their edaphic constraints, together with climatic limitations, constitute a major bottleneck for fertility and productivity in key arid regions worldwide. This narrative review provides a taxonomic and edaphic framework to guide sustainable SFL-systems and integrates current approaches and technological applications for forage production in arid environments, focusing on an edaphic-digital scheme that combines organic and inorganic soil amendments with AI-based decision support to improve Aridisols productivity and resilience. Searches of the literature (ScienceDirect, EBSCOhost, Clarivate Web of Science; English, 2021–2025) screened 309 records and selected 169 references; seminal older works were consulted for context. Representative quantitative outcomes from the reviewed literature include SOC increases of ~15–30% after multi-year organic inputs; forage biomass gains of ~10–25% following amendments that correct sodicity; and water-productivity improvements up to ~30% with hydrogels or biochar. AI tools can improve soil diagnostics and amendment selection (diagnostic accuracy improvements of ~15–30% in recent studies) and generate predictive models of amendment–response that facilitate optimization of application rates and water use. The novel contribution of this review is the explicit linkage of SFL-systems and amendment-based soil restoration with AI-driven diagnostics and decision support, providing actionable metrics and research priorities to translate digital diagnostics into measurable forage gains in arid and semi-arid regions. Overall, the evidence suggests that targeted soil restoration, reinforced by AI-based support systems, is a feasible strategy to increase forage availability and ecosystem service provision in drylands.
For hydrological parameterization in high-Andean catchments, it is necessary to understand whether near-surface hydro-structural soil properties can provide a surrogate signal of particle-size composition when direct texture information is sparse. This study evaluated the extent to which sand, silt, and clay fractions can be approximated from organic matter (OM), bulk density (ρb), and saturated hydraulic conductivity (Ksat) in the Zamora Huayco (ZH) and Irquis catchments, southern Ecuador. A harmonized dataset (n=44) was analyzed through exploratory statistics, compositional assessment, correlation analysis, PCA, fraction-wise regression, ILR-based modeling, AIC/BIC term reduction, sensitivity analysis excluding OM, nested LOOCV, and bootstrap-based uncertainty intervals. Among LULC classes, samples classified as paramo occupied a distinct high-Andean hydro-edaphic domain, characterized by a differentiated relationship between soil physical properties and hydrological behavior. PCA showed that the dominant covariance structure involved OM, ρb, Ksat, and the redistribution between sand and silt. The BIC-reduced ILR model provided the most balanced formulation, with positive nested LOOCV performance for sand, silt, and clay (RLOOCV2=0.147, 0.704, and 0.124, respectively) and exact 100% compositional closure after inverse transformation. Silt was the most stable predicted fraction, whereas sand and clay retained larger residual uncertainty, stronger tail departures, and partial compression of the observed variability. The proposed equations provide local hydro-pedotransfer support, although their predictive signal remains dependent on further refinement, uncertainty assessment, and external validation before regional application.
Reactive oxygen species (ROS) are a class of molecules or free radicals with strong oxidizing properties. They have attracted increasing attention in soil research in recent years because of their perceived importance in many soil biochemical processes. Previous reviews of ROS in soil mainly focused on their impacts on carbon emissions and organic pollutant remediation, with few descriptions of the mechanisms responsible for ROS generation, and a comprehensive understanding of their environmental effects is still lacking. Therefore, the present review provides details on the sources and underlying generation mechanisms of ROS in soil. These mechanisms include inputs via atmospheric deposition, metal–mineral reactions, root exudation, microbial metabolism, enzymatic reactions and various organic matter transformations. In contrast to previous reviews, we also discuss mutual conversion between different types of ROS in soil. The impacts of ROS on the soil environment are further explored, such as element cycling, pollutant degradation, and the growth and reproduction of plants and microorganisms, in order to provide a systematic understanding of the various processes involving ROS in soil, thereby guiding better soil management decisions. Finally, we highlight future research trends, suggesting that the advancement of in situ detection methods is crucial for establishing the precise contribution of abiotic ROS processes to global soil carbon and nutrient models.
This study aimed to disentangle the relative influence of inherent soil properties and annual starter P fertilization on active carbon (C) pools and C-, nitrogen (N)-, and phosphorus (P)-cycling enzyme activities in silage corn production systems with high-legacy P. Six fields with Mehlich-3 P ranging from 53.5 to 332 mg kg−1 were investigated in 2020 and 2021 in the Fraser Valley, Canada. The experiments at each site consisted of five starter P rates (0, 5, 10, 15, and 20 kg P ha−1 as triple super phosphate) arranged in a randomized complete block design with four replicates. Soil samples were collected at the V3 and V6 stages of silage corn and analyzed for active C, soil enzyme activities, and chemical properties. N-acetyl-β-glucosaminidase varied significantly across the six sites, suggesting substantial differences in the rate of C and N cycling. For instance, in 2020, N-acetyl-β-glucosaminidase was similar at Sites 1 and 2 at V6 and was approximately three times (514.51 pmol MUF g−1 soil h−1) higher than at Site 3 (170.29 pmol MUF g−1 soil h−1). Similarly, in 2021, a 2.8-fold higher MBC observed at Site 4 at V6, compared with the averages of Sites 5 and 6, further confirms an active C pool. Meanwhile, sites with the lowest MBC concentrations were linked to acidic soils (pH 5.3), and a negative correlation between inherent site–year characteristics and enzyme activities confirm enzymes repression. Acid phosphatase at Site 4 was 3-fold higher than at Site 5 and Site 6, while alkaline phosphatase was detected only at Site 4. We conclude that long-term soil conditions are the main factors influencing biological functionality, thereby overshadowing transient fertilization. This indicates that Fraser Valley farmers can prioritize long-term soil health management and safely reduce starter P applications in these high-legacy systems.
Elemental mercury has been used in the production of bleach since at least 1892 and continues to be utilized in some manufacturing processes today. This case study examines a former bleach manufacturing facility in the western United States, where elemental mercury was utilized as an electrical conductor in the chlor-alkali process to produce chlorine and sodium hydroxide, essential constituents in bleach formulation. The operational practices implemented at the facility led to the discharge of elemental mercury into both soil and groundwater. Subsequent investigations identified the presence of mercury in indoor air at levels surpassing the screening thresholds established by the California Environmental Protection Agency (CalEPA) Department of Toxic Substances Control (DTSC) and the United States Environmental Protection Agency (USEPA) for commercial exposure scenarios. Additionally, these concentrations exceeded the California Office of Environmental Health Hazard Assessment (OEHHA) acute 1 h reference exposure level (REL). The origins of mercury in indoor air have been identified as vapor intrusion associated with subsurface sources, along with a potential secondary indoor air source associated with mercury deposition and adsorption in building materials through the years. In the context of interim vapor intrusion mitigation, air purifiers and fans were deployed to enhance air exchange rates, while a comprehensive assessment led to the identification and sealing of 52 preferential pathways. Even with these interim vapor intrusion mitigation systems in place, elevated concentrations of elemental mercury are still present in the building and may represent the presence of a secondary indoor air source from accumulation of elemental mercury in building materials.
Green undersown crops (GUCs) are increasingly promoted as a sustainable management strategy to improve soil quality and ecosystem services in Mediterranean orchards, particularly in the calcareous, low-organic-matter soils typical of Eastern Spain. In this context, soil quality is understood as the soil’s overall functional capacity, integrating physical structure, chemical balance, and biological activity, whereas soil fertility refers specifically to the soil’s ability to supply nutrients to plants; soil quality therefore encompasses a broader set of ecosystem functions beyond nutrient provision. However, their effects on the calcareous, low-organic-matter soils typical of Eastern Spain remain insufficiently quantified. This study evaluates the effects of seeded undersown (grasses, legumes, and flower mixtures), spontaneous vegetation, and herbicide-managed bare soil on topsoil (0–15 cm) physicochemical and biological indicators in 54 plots across three irrigated persimmon orchard sites (Granja, Cargol, and Alginet) over 18 months of treatment in the València region (Eastern Spain). Seasonal sampling was conducted at the START (early winter) and END (late spring) of the experiment period. Soil measurements at both sampling times included soil organic matter (SOM), nitrogen (N), C/N ratio, pH, electrical conductivity (EC), soil respiration rate (RR), collembolan abundance, mite abundance, and the QBS-ar index of soil arthropods. Legumes increased SOM by +1.12%, grasses by +0.22%, whereas flower mixtures (−0.44%) and spontaneous vegetation (−1.36%) showed SOM reductions associated with rapid biomass turnover. RR increased under all GUCs (+0.06 to +0.16 g CO2 m−2 h−1), and QBS-ar improved markedly under grasses (+26.6) and spontaneous vegetation (+36.7). EC decreased across all treatments (−16 to −84 µS cm−1). These results were analysed using principal component analysis (PCA). Four PCA components explained 74% of the total variance, revealing functional gradients driven by SOM, N, EC, RR and mesofauna. After 18 months, microbial biomass carbon (MBC) increased by +45–60% under legumes, water-soluble organic carbon (WSOC) by +30–50% under legumes and flower mixtures, and the enzyme activities (EA) by +20–40% under all GUCs. Herbicide-managed soils showed reduced biological activity and detectable residues of glyphosate and oxyfluorfen. PCA and linear discriminant analysis (LDA) were used to identify functional gradients and treatment separation. GUCs significantly increased SOM, MBC, EA, and mesofauna abundance compared with herbicide treatments, which showed reduced biological activity and detectable residues of glyphosate and oxyfluorfen. Legumes and flower mixtures produced the strongest improvements in biological functioning due to higher MBC, WSOC, EA and RR. PCA and LDA confirmed clear separation between GUCs and herbicide-managed soils based on multivariate differences in SOM, N, EC, RR, MBC, WSOC and mesofauna indicators. Overall, GUCs modulated soil chemistry and biodiversity and enhanced soil functioning and biological quality, supporting their adoption as a sustainable management strategy in Mediterranean orchards. Legume-based covers are recommended for rapid biological activation, whereas grass-based covers favour longer-term SOM stabilisation. These findings highlight their role as key tools for improving soil resilience in Mediterranean persimmon orchards.
Human health risk assessment of vapor intrusion caused by organic pollutants is commonly based on steady-state predictions of partition and vapor migration in the subsoil. This study develops a pseudo-dynamic, process-based Partition–Diffusion Risk Model (PDRM) using a one-dimensional numerical model for organic mixtures to assess the time evolution of cancer and non-cancer risks, indoor air concentrations, and non-aqueous phase liquid (NAPL) formation. The model has been applied to a low-carbon sandy soil without microbial degradation, which might be a worst-case scenario. Six simulation scenarios combined two source concentrations (1000 and 3000 mg/kg) and three source depths (1, 3, and 5 m) over 30 years. Results show that source depth governs exposure dynamics: shallow contamination poses unacceptable risks rapidly but declines quickly, whereas at greater depths, unacceptable levels appear later and persist throughout the exposure period. NAPL formation may act as a secondary source, sustaining vapor release and extending indoor exposure under high-loading conditions. Multicomponent partitioning induces nonlinear, compound-specific behavior, with the first 3–5 years representing a critical period for rapid risk changes. Conventional models show that neglecting NAPL formation and time variability may lead to an underestimation of cancer risk by up to an order of magnitude. These findings highlight the importance of incorporating depth and time-dependent characterization to reduce uncertainty in vapor intrusion risk assessments.
Replacing peat in green roof substrates with sustainable alternatives while maintaining plant performance and ecosystem services remains a critical challenge. We studied biochar-substrate interactions across four commercial green roof formulations (based on the type of organic component) in a greenhouse experiment: pure vermicompost, vermicompost + fen peat, fen peat, and mixed fen/high-moor peat. Substrates were amended with straw biochar, pine bark biochar, or left unamended (5% v/v, n = 4 replicates) and planted with a grass seed mixture mimicking early green roof establishment. Plant growth, nutrient contents (nitrate and phosphate contents), and microbial indicators (microbial biomass carbon (MBC), qCO2, and enzyme activities) were measured 30 days after the experiment began. Straw biochar in vermicompost boosted nitrate (90.8 mg kg−1) and root N (3.1%) compared to the control, while pine bark biochar in mixed peat released phosphate (+375%) and maximized MBC (874 µg g−1). Biochar intensified substrate effects, suppressing CO2 in peat through liming effects (pH from 4.6 to 6.5–7.1) but priming respiration in vermicompost via labile C supply. PCA explained 63% of the variance, with nitrate, plant N, and microbial parameters driving substrate separation. These short-term greenhouse results demonstrate critical biochar-substrate specificity for green roof substrate development, emphasizing formulation-specific matching over universal biochar application.
Conventional tillage, a soil preparation practice used to produce a fine seedbed, can disturb the soil profile by promoting soil compaction and soil organic matter (SOM) degradation. In contrast, conservation tillage, such as no-till, has the potential to sustain or increase SOM. This study aimed to (1) quantify soil organic carbon (SOC) content under conservation tillage and conventional tillage practices, (2) describe the degree of aromaticity of bioavailable SOC using fluorescence spectroscopy, and (3) correlate SOC quantity with nitrogen and phosphorus retention in soils. Fluorescence spectroscopy is a sensitive and non-destructive tool that allows for the assessment of bioavailable SOC quality related to the molecular structure, degree of aromaticity (cyclic molecules with carbon double bonds), and recalcitrance (difficulty of decomposition) of organic compounds. This study employed fluorescence excitation-emission matrices combined with parallel factor analysis (EEM-PARAFAC) to identify humic-like, fulvic-like, and protein-like substances. Data on agricultural management practices were collected from spring 2014 until fall 2017. We obtained soil samples (fall 2017) from farms in the Western Lake Erie Basin, Ohio, and performed geochemical characterization in the bulk soil and aqueous extraction. Our results showed that no-till and minimal tillage fields consistently had greater SOC and fluorescence intensity in the humic-like acids region when compared to conventional tilled fields (no-till: 34,000 mg TOC kg-1; tilled six times: 16,000 mg TOC kg-1). No-till enhanced SOC stabilization. In addition, conservation tillage practices retained the largest total nitrogen (no-till: 2800 mg TN kg-1; tilled six times: 1350 mg TN kg-1) and total phosphorus (no-till: 470 mg TP kg-1; tilled six times: 250 mg TP kg-1) concentrations at all studied depths (0-30 cm) when compared to conventional tilled fields. Conservation tillage promotes the accumulation of highly aromatic organic compounds favoring high cation exchange capacity, and NO3- and PO43- retention and plant bioavailability.
Co-utilization of milk vetch as green manure (GM) and rice straw is an effective practice for reducing nitrogen (N) input while maintaining crop productivity in rice-based agroecosystems in southern China. The effects of soil carbon (C) and N pools and their fractions under green manuring and rice straw return, combined with reduced N fertilization remain to be clarified. A four-year field experiment was carried out to explore the effects of synergistic utilization of GM and rice straw (GMS) on rice yield, soil C and N fractions, and their contributions to rice productivity. The study demonstrated that compared with winter fallow (WF), GMS increased rice yield by 20.3% under 40% reduction in N fertilization (N60). GM application increased soil total N content by 16.5% and 18.0% significantly relative to WF under N0 and N60, respectively. GMS treatment demonstrated improvements in the soil organic C pool and enhanced soil N activity. Compared with WF, soil organic C, mineral-associated organic C and particulate organic C under GMS increased by 11.1% and 24.9%, 31.3% and 13.8%, 13.1% and 47.3% at N0 and N60 levels, respectively. Under N60, GMS increased heavy-fraction organic C content by 42.6% while reducing light-fraction organic C content by 28.0% compared to WF, thereby enhancing soil C pool stability. Regarding soil N fractions, GMS increased particulate organic N content by 60.8% and 79.3%, and mineral-associated organic N content by 89.7% and 43.4% at N0 and N60 levels, respectively. Under N60, GMS reduced heavy-fraction organic N content while increasing light-fraction organic N content, thereby enhancing soil N availability. Based on the results of Mantel tests and random forest prediction, our analysis found that N and particulate organic C served as the key factors affecting rice yield. In conclusion, GMS combined with 60% of the conventional N rate enhanced rice yield by mediating soil C sequestration and N availability, proving to be an effective strategy for improving soil fertility and ensuring food security in the rice-growing region of southern Jiangsu, China.
Soil erosion is a significant environmental concern in arid regions, particularly in dam-regulated watersheds, where intermittent flows from sprinkler irrigation can exacerbate land degradation. This study assesses soil erosion susceptibility in the Sidi Aich watershed using a combined approach of the Revised Universal Soil Loss Equation (RUSLE) and the Analytic Hierarchy Process (AHP), enabling the integration of both regional characteristics and expert-driven weighting. The RUSLE model accounts for natural and human-induced factors, whereas AHP provides a hierarchical weighting system that highlights rainfall erosivity and the local impacts of dam-regulated discharges. Results show that 26.12% of the area falls into the very high susceptibility category, 25.45% into high, 23.91% into moderate, and 24.51% into low susceptibility. Model validation demonstrates satisfactory predictive performance, with Area Under the Curve (AUC) values of 0.85 for AHP and 0.78 for RUSLE. Overall, the findings emphasize the critical role of dam-controlled releases in increasing soil vulnerability, a factor that may not be fully captured when using RUSLE alone. By combining RUSLE and AHP, this research provides a more realistic and regionally tailored assessment of erosion risk, offering valuable guidance for watershed management and erosion mitigation strategies in arid environments.
Vegetation strongly influences soil formation, yet its effect on Rare Earth Element (REE) distribution and fractionation across treeline ecotones remains insufficiently constrained. The present study investigated how contrasting plant communities, Vaccinium myrtillus heathlands and Picea abies forests, affect pedogenetic pathways and REE behavior in sandstone-derived soils of the Northern Apennines (Italy). Six soil profiles were characterized for bulk geochemistry, selective Fe-Al extractions, particle-size distribution, and REE concentrations. Principal component analysis and hierarchical clustering identified pedogenetic drivers and horizon groupings. Under Vaccinium myrtillus, thick acidic organic horizons promoted organo-metal complexation and incipient podzolization, whereas Picea abies soils showed thinner organic layers and enhanced mineral weathering, leading to Bw development with higher silt-clay contents and elevated Al/N ratios. These pathways were captured by Fe-Al indicators and the Spodic Index. REE distributions showed vegetation-related differences in surface horizons and Eu-Ce anomalies, but they did not reproduce Fe-Al pedogenetic clusters, reflecting strong parent-material control. The coexistence of podzolic and cambic pathways at the treeline highlights pronounced spatial heterogeneity and vegetation effects. Plant composition may redirect pedogenesis, influencing nutrient cycling and metal mobility. Additionally, these findings emphasize the need to integrate multivariate statistics with established pedogenetic indicators when evaluating geochemical properties in mountain soils.
This study is the first to investigate volcanic ash (VA) as a soil amendment to mitigate nitrous oxide (N2O) emissions, a potent greenhouse gas mainly produced through nitrification and denitrification processes in agricultural soils. The experiment assessed the effects of VA mixed with soil and combined with mineral (NH4NO3, N) or organic (poultry manure, O) fertilizer on N2O emissions, soil mineral nitrogen (NO3- and NH4+), trace metals (Zn, Cu, Mn), and crop yield in a 4-month pot experiment including treatments with and without VA. Results showed that VA reduced N2O emissions by 55% in mineral fertilizer treatments and 71% in organic fertilizer treatments compared to soils without VA. This reduction was associated with significant changes in nitrogen availability. In mineral fertilizer treatments with VA, soil NO3- concentrations remained high, potentially limiting denitrifier activity, while in organic treatments VA appeared to inhibit nitrogen mineralization. Additionally, VA increased soil concentrations of Zn, Cu, and Mn, which were negatively correlated with N2O emissions, suggesting an influence on microbial processes. Importantly, crop yields were not affected by VA application. Although promising, these preliminary findings highlight the need for further research to optimize application rates and evaluate long-term effects across soil types and management systems.
