Search Results (1,157)

Pig slurry management is a challenge in livestock-intensive agricultural areas, where sustainable reuse requires field applications to be translated into measurable and controllable doses. This study evaluated a field-adapted calibration procedure for pig slurry application in a Mediterranean cereal field in southern Spain, particularly for spreading equipment without built-in dose-control systems. Slurry delivery was quantified by direct field collection and weighing and related to the number of tractor passes. Three management scenarios were evaluated: a non-amended control, one pass per application event, and two passes per application event. Soil properties were monitored before slurry application and during two subsequent sampling campaigns. Short-term responses were mainly observed in soil chemical properties, with increases in organic matter and total nitrogen after application and transient changes in available nutrients, whereas the evaluated physical properties showed temporal variation without a consistent slurry-specific pattern. Increasing slurry application did not consistently result in proportional or more persistent soil responses. Given the limited field replication, these findings should be interpreted as exploratory. Overall, the proposed calibration procedure provides a practical framework for converting tractor passes into measurable slurry and nutrient applications that can be adapted to local equipment, slurry characteristics, agronomic requirements, and regulatory conditions. Full article

Terrestrial soils represent a dominant source of atmospheric nitrous oxide (N₂O), with emissions governed by complex interactions among various biotic, abiotic and microbial drivers. A dataset (n = 275 study sites/plots) that integrates field and laboratory measurements of soil N₂O emissions with corresponding environmental drivers was compiled from the peer-reviewed literature. A quantitative hierarchical framework was refined to clarify the interactions among these drivers and their regulatory effects, which are mediated through a three-level mechanistic pathway. At the primary level, environmental drivers (e.g., air temperature, precipitation, site location) act as foundational constraints on soil physical properties (e.g., soil temperature, moisture regime, texture). At the secondary level, the soil’s physical properties create the conditions for soil microbes through influencing chemical properties. At the tertiary level, soil chemical drivers (e.g., the contents of soil organic carbon, nitrogen, ammonium and nitrate; carbon-to-nitrogen ratio) exert direct influences on the N₂O flux through modulating the soil’s biotic conditions, affecting microbe community composition and the metabolic activities of microbes. However, these regulatory effects only function when the previous abiotic conditions fall within permissive thresholds. The framework also demonstrates the interactions among biotic and abiotic drivers. This study highlights that future studies should pay greater attention to soil-type- or ecosystem-specific abiotic thresholds and quantify their interactions to improve the simulations of soil N₂O fluxes to the atmosphere at either regional or global scales. Full article

Shrub encroachment in alpine grasslands alters soil biogeochemical processes, but reported soil responses remain inconsistent and conflicting among studies. We performed a systematic review and meta-analysis to evaluate ten physical and chemical alongside biological soil properties. Evaluated indicators covered soil water content (SWC) and bulk density (BD) alongside soil organic carbon (SOC) and total nitrogen (TN). They also included ammonium (NH₄⁺-N) and total phosphorus (TP) and pH alongside microbial biomass carbon (MBC) and nitrogen (MBN) and phosphorus (MBP). In total, 66 peer-reviewed articles provided 175 paired observations across four continental alpine regions, with most studies conducted in High Mountain Asia. Most compiled studies evaluated topsoil chemical properties, while non-nitrogen-fixing shrubs dominated the dataset. Shrub encroachment significantly stimulated MBC (+7.59%) and MBN (+5.44%) across both functional groups. TN increased significantly (+2.08%) driven entirely by nitrogen-fixing shrubs (+7.57%). Nitrogen-fixing shrubs also induced rhizosphere acidification (−1.87%) and increased MBP (+14.41%). Non-nitrogen-fixing shrubs significantly reduced BD (−5.67%), while bulk SOC (+0.15%) and TP (−0.31%) showed no pooled change. SOC responses diverged sharply at the genus level, increasing under Dasiphora (+6.58%) but declining under Salix (−6.88%) and Vaccinium (−11.62%). Soil sampling depth and shrub genus identity exerted primary controls on soil carbon and nitrogen dynamics. Current evidence concentrates heavily on Qinghai–Tibetan Plateau topsoils, leaving critical geographic and subsoil data gaps across global cold alpine biomes. Given functional divergence and depth stratification, sustainable alpine management must adopt shrub regulation differentiated by functional traits, linking microscale microbial processes with whole ecosystem carbon and nitrogen cycling. Full article

Traditional evaluations of ecological restoration in mining lands have long been dominated by above ground vegetation metrics, such as coverage and community diversity. Yet in arid and semi-arid mining regions, soil hydrology recovery is key, as soil organic carbon (SOC) and bulk density (BD) are critical factors affecting soil hydrology. However, their thresholds for water holding capacity and infiltration remain unclear. Therefore, this study determined the SOC and BD thresholds and evaluated the hydrological trends across them. The study was in a Loess Plateau coal reclamation area. Five restoration types and one reference forest were selected, and soil samples were collected from the 0–10 cm layer. Redundancy analysis (RDA), partial least squares structural equation modeling (PLS–SEM), and the threshold regression model were used for analysis. Results show the following: (1) Vegetation indirectly controls soil hydrology via soil structure and chemical properties (RDA: 76.04%). BD limited water holding capacity (path coefficient: −0.908), while chemical properties promoted infiltration (path coefficient: 0.397). (2) Soil hydrological recovery exhibits non-linear threshold responses. The SOC thresholds for water holding capacity and infiltration were 9.52 g/kg and 5.93 g/kg, respectively, while the BD thresholds were 0.93 g/cm³ and 1.03 g/cm³. The reclamation of soil hydrological functions in mining lands follows a two-stage mechanism. First, control by carbon accumulation, then follow by structural dominance. During the early stage, soil organic carbon (SOC) buildup quickly boosts hydrological performance by promoting aggregate formation. However, once the system nears its functional threshold, simply adding more carbon gives limited returns. At this stage, breaking through physical constraints becomes vital to overcoming the bottleneck. Above-ground metrics alone cannot capture below-ground ecosystem functional trajectories. Consequently, a dynamic strategy centered on SOC and BD is proposed. Full article

As the unique edible nut species in China, Chinese hickory (Carya cathayensis Sarg.) is vulnerable to anthropogenic disturbances that reduce vegetation residue inputs and soil organic matter accumulation. To investigate the effects of net-harvesting-associated understory management on the soil carbon pool management index (CPMI), soil samples were collected from C. cathayensis plantations subjected to net harvesting for 2, 3, 6, and 7 years, with traditional beating as the control. Long-term net harvesting significantly increased particulate and dissolved organic carbon, microbial biomass carbon, and labile organic carbon (p < 0.05). It also altered soil enzyme activities, microbial community composition, and microbial co-occurrence network complexity. Soil physical and chemical properties and carbon pools were key drivers of enzyme activities and microbial complexity. Partial least squares path modeling (PLS-PM) revealed that understory vegetation positively influenced the CPMI (total effect = 0.57), while soil biological processes also contributed to CPMI variation. Overall, net harvesting reduced anthropogenic disturbance, enhanced litter-derived carbon inputs, and promoted soil biological functions, thereby improving the CPMI. These findings provide insights into sustainable soil management and carbon sequestration in C. cathayensis plantations. Full article

This study aimed to investigate the effects of γ-polyglutamic acid (γ-PGA) on the physicochemical properties and enzyme activities of coal gangue-based soils, focusing on how different application rates influence soil indicators and enzyme functions for ecological restoration. Soil samples with varying weathering ages were collected from a coal gangue pile, and a pot experiment was conducted with five γ-PGA treatments (0–43.2 g dissolved in 300 mL water). Soil pH, electrical conductivity, nutrient contents, aggregate composition, and enzyme activities (urease and sucrase) were measured, and redundancy analysis (RDA) was applied to evaluate the relationships between soil properties and enzyme activities. γ-PGA rapidly increased soil pH and altered conductivity trends. Its effects on organic matter, nitrogen, phosphorus, and potassium were complex and dependent on both dosage and time. Optimal γ-PGA addition enhanced organic matter and nitrogen transformation, increased potassium availability, and modified water-stable aggregate distribution. Enzyme activities were significantly affected by γ-PGA dosage, exhibiting distinct initial levels and temporal trends across soils of different weathering ages. RDA revealed clear differentiation in soil properties under different treatments, with enzyme impacts evolving over time. DFT results revealed a distinct valence-dominated ion-binding hierarchy, with trivalent cations (Al³⁺, Cr³⁺, Fe³⁺) showing the strongest affinity, followed by divalent cations and monovalent ions/oxyanions. Overall, γ-PGA markedly improves the quality of coal gangue-based soils, providing theoretical guidance and practical reference for ecological restoration and soil management strategies. Full article

This study evaluates the effectiveness of water-soluble epoxy resin for stabilising clay soils in the design of column-type reinforcement in soft ground. To evaluate the influence of varying mix proportions of epoxy resin on the strength of a stabilised silty clay soil, specimens were subjected to a series of unconfined compression tests at various curing ages. In addition, undrained unconsolidated, isotropically consolidated undrained, and isotropically consolidated drained triaxial tests were conducted on specimens after 180 days of curing. Finally, the dynamic behaviour of the treated soil was investigated via isotropically consolidated undrained cyclic triaxial testing. Furthermore, the effect of incorporating epoxy resin on the key physical properties was assessed via water permeability, porosity, and viscosity measurements. The experiments showed that the use of this resinous material resulted in an appreciable increase in all strength values. Moreover, all stabilised specimens exhibited a substantial improvement in cyclic properties, with failure occurring at significantly elevated stress levels and after enduring a larger number of loading cycles, compared to their untreated counterparts. The laboratory results presented here offer critical guidelines for future experimental studies aimed at improving the efficacy of this material in the chemical treatment of weak soils and deep soil mixing applications. Full article

The Northeast black soil region is a major grain-producing area in China, where county-scale assessment of topsoil quality is essential for soil conservation and provides a potential indicator framework for regional soil quality monitoring. In this study, 500 composite cultivated-layer samples were collected from dryland croplands in Keshan County, Heilongjiang Province. Soil physical properties, basic chemical properties, and macro-, secondary, and micronutrient contents were measured to establish a total data set (TDS). Three hierarchical total data sets (TDS1, TDS2, and TDS3) were established from the original TDS according to the progressive incorporation of soil physical properties, basic chemical properties, macronutrients, secondary nutrients, and micronutrients. Within each hierarchical TDS, key indicators were selected using random forest (RF), mutual information (MI), principal component analysis (PCA), and minimum spanning tree (Tree) methods to construct algorithm-specific minimum data sets (MDSs). TDS1 included soil physical properties, basic chemical properties, and macronutrients; TDS2 further incorporated secondary nutrients; and TDS3 additionally included micronutrients to represent progressively comprehensive soil nutrient information. The soils exhibited considerable soil organic matter and cation exchange capacity, with mean values of 51.45 g kg⁻¹ and 34.85 cmolc kg⁻¹, respectively, and a mean pH of 6.04. Across the four algorithms, commonly retained indicators included SOM, TN, pH, CEC, and Silt, while nutrient-related indicators such as AP, AK, S, Zn, and Fe were additionally selected under different hierarchical MDSs, reflecting the importance of multi-nutrient information in soil quality characterization. Available phosphorus, available potassium, sulfur, and zinc showed greater spatial variability than basic physicochemical properties. The four algorithms differed in indicator selection, reflecting their distinct sensitivities to linear variation, information gain, multilevel contributions, and network structure. RF_MDS1 showed the highest agreement with the TDS (R² = 0.924), indicating its strong capability in preserving overall soil quality information using a simplified indicator set. RF_MDS3 maintained a high consistency with the TDS (R² = 0.836) while incorporating additional secondary nutrients and micronutrients. Therefore, RF_MDS3 was considered a more comprehensive MDS framework when multi-nutrient representation and potential nutrient constraint identification were prioritized, whereas RF_MDS1 remained an efficient option for simplified soil quality assessment. This framework may provide a transferable approach for soil quality assessment and nutrient management in comparable black-soil regions and dryland farming systems. Full article

Per- and polyfluoroalkyl substances (PFASs) are persistent, surface-active contaminants for which soil represents the largest terrestrial reservoir. This review synthesizes a rapidly expanding but fragmented body of literature in order to reframe PFAS not merely as a groundwater transport problem but as a systemic stressor of soil health, drawing together their reported effects on the chemical, physical and biological properties of soils and giving particular attention to the calcareous, alkaline, carbon-poor and seasonally dry soils of the Mediterranean. The reviewed evidence suggests that, chemically, PFASs perturb the coupled carbon and nitrogen cycles rather than the bulk soil reaction, transiently stimulating and then depressing organic carbon turnover, drawing down the dissolved organic carbon pool and disturbing nitrification, while their retention and bioavailability are governed chiefly by organic carbon, chain length and pH. Physically, the surfactant character that defines these molecules lowers the surface tension of soil water and concentrates PFASs at the air–water interface, so that in unsaturated and drought-prone soils much of the burden is retained and then released episodically, most clearly on rewetting after dry periods. Biologically, the literature consistently reports dose-dependent declines in microbial viability, diversity and enzyme activity, alongside toxicity to earthworms and other soil fauna, with sensitivity strongly modulated by soil texture and organic matter. Across all three domains, the Mediterranean emerges as both potentially vulnerable and conspicuously understudied, the available data being clustered in a few western countries and effectively absent for much of the eastern and southern basin, so that the regional assessment offered here rests largely on mechanistic inference rather than on direct observation. The review argues that these coupled mechanistic and geographic gaps define an urgent, region-specific research agenda for the protection of soil health. Full article

Electrochemical corrosion is one of the main causes of degradation of substation grounding devices and directly impacts the operational reliability of electric power facilities. Despite numerous studies on individual corrosion factors, comprehensive models considering the combined effects of soil physical and chemical properties and electrical operating conditions remain limited. This study analyzes emergency situations associated with grounding system failures and examines the effect of the main factors of electrochemical corrosion, including chloride ion concentration, soil moisture, environmental acidity, seasonal temperature changes, and leakage currents. Based on Faraday’s law, a mathematical model of electrochemical corrosion rate is proposed that combines the influence of the factors considered through correction factors. For practical implementation, an algorithm for the dynamic assessment of degradation of grounding system elements has been developed. The proposed model predicts changes in the cross-sectional area of grounding device elements, changes in grounding resistance, and the occurrence of potentially hazardous operating conditions. The developed algorithm assesses the risk of exceeding the permissible grounding potential, violating thermal withstand, the occurrence of hazardous step voltages, insulating breakdown, and disrupting the selectivity of relay protection devices. Full article

Organic fertilization is a key strategy for improving soil structure and fertility in China’s Vertisols, yet the trade-offs among soil quality enhancement, grain yield performance, and nutrient use efficiency under different organic amendment regimes remain insufficiently elucidated. Based on a unique 43-year field fertilization experiment, this study systematically evaluated the effects of long-term chemical fertilization (NPK) alone, low-dose (NPKLS) and high-dose straw incorporation (NPKHS), combined chemical fertilizer with cattle manure (NPKCM), and pig manure (NPKPM) fertilization on soil physical, chemical properties, crop yields and plant nutrient utilization efficiency. The results showed that NPKCM and NPKPM significantly improved soil physical properties by reducing soil bulk density, improving soil pore structure, and enhancing soil water retention capacity and saturated hydraulic conductivity. Although long-term manure application led to slight soil salt accumulation, the rate of accumulation remained substantially lower than that associated with commercial organic fertilizers and did not approach the crop salinity damage threshold, suggesting low ecological risk. Compared with NPK treatment, manure amendment effectively counteracted soil acidification induced by prolonged chemical fertilization, while also significantly increasing soil total phosphorus and available phosphorus content, and elevated the proportion of active phosphorus (PAC). The improved soil phosphorus activation capacity and comprehensive soil quality further contributed to substantial increases in wheat grain yield under NPKCM and NPKPM treatments. Despite these agronomic benefits, the additional nitrogen and phosphorus inputs from manure resulted in soil nutrient surpluses, which considerably reduced nitrogen and phosphorus partial factor productivity as well as agronomic efficiency. In contrast, straw incorporation treatments (NPKLS, NPKHS) sustained stable crop yield without notable declines in nutrient efficiency, positioning them as a greener and more sustainable approach to balancing grain production with resource use efficiency. These findings highlight the need to integrate nutrient credits from manure into fertilization program. Given the 43-year evidence, fertilization strategy should consider not only the nutrients supplied by manure but also the quantities exported through harvested products, with adjustments based on annual soil fertility analyses. Such nutrient budgeting is essential to maximize fertilizer use efficiency, prevent excessive phosphorus accumulation, and maintain balanced soil fertility over time. Full article

Urban soils are central to ecological functioning and urban resilience and have value not only for the services they provide to people but also for their intrinsic ecological worth. However, this ecocentric dimension remains underrepresented in urban sustainability research and practice. This study examines how urban soil management can be transformed to incorporate ecocentric values of nature by analysing both the practices through which this transformation can be achieved and the barriers that stand in the way. Based on a survey of 80 urban practitioners conducted in 2023, the study explores stakeholder roles, value orientations, soil indicators, regenerative practices, and perceived barriers to implementation. The results show that nearly all respondents recognised at least one explicit value of urban soil (95%), and a majority (60%) attributed several values at once, with future and intrinsic values each recognised by a substantial share of practitioners (65% and 50%, respectively), suggesting that ecocentric framings are present among a substantial share of practitioners. Whether this recognition translates into practice is more limited: about half of the respondents (51%) consider soil properties in their professional practices. Soil assessment is predominantly based on physical and chemical indicators, with biological indicators receiving comparatively little attention. The central empirical finding of this study is a pronounced awareness–action gap specific to soil regeneration: 96% of respondents recognise the importance of soil regeneration, yet only 40% report implementing regenerative practices. Regeneration, understood here as the restoration of biological activity and natural soil processes, is conceptually located towards the ecocentric pole of an anthropocentric–ecocentric continuum, since it engages with soil as a living system with intrinsic value rather than as a substrate for human use. Respondents identify knowledge gaps, fragmented governance, and financial constraints as key barriers to wider adoption, which indicates that the principal barriers are structural and institutional in nature; a lack of practitioner commitment does not appear to be the issue. Embedding ecocentric values in everyday practice will require integrating biological indicators into standard soil assessments, strengthening knowledge exchange through living labs and practitioner-oriented tools, and extending soil health targets across the policy, procurement, and funding mechanisms that govern urban development. Full article

Selecting suitable agricultural land is critical for food security and sustainable development, particularly in arid regions facing resource scarcity and environmental degradation. This study assesses agricultural land suitability in Sohag governorate, Egypt, using a hybrid Geographic Information System (GIS), Fuzzy Analytical Hierarchy Process (FAHP) and geostatistical approach. Thirty-four representative soil profiles were morphologically described and analyzed for ten physical (slope, depth, erosion, texture, stoniness, drainage) and chemical (EC, pH, CaCO₃, organic matter) criteria, weighted using both the Analytical Hierarchy Process (AHP) and FAHP. Geostatistical analysis characterized the spatial variability in soil properties across the study area. The two suitability maps were validated using Receiver Operating Characteristic (ROC) curves and Kappa statistics: the FAHP achieved higher prediction accuracy (AUC = 0.83, Kappa = 0.91) than the AHP (AUC = 0.81, Kappa = 0.88). The AHP-based map classified 40% (1154.92 km²) as moderately suitable (S2), 33% (952.81 km²) as marginally suitable (S3), and 27% (779.57 km²) as unsuitable (N); the FAHP-based map classified 42% (1212.67 km²) as S2, 30% (866.19 km²) as S3, and 28% (808.44 km²) as N. The proposed framework may serve as a reference for similar arid environments and support progress toward Sustainable Development Goals 2, 6, 8, 9, 11, 13 and 15, conditional on local soil, water, climate and management conditions. Full article

Soil acidity is one of the most serious constraints limiting crop productivity in regions with high rainfall in Ethiopia. To address this issue, field experiments were conducted during the 2024 main cropping season in farmers’ fields in two distinct ecological locations. This study aimed to explore the response of soil chemical properties and wheat (Triticum aestivum L.) to organic and inorganic amendments of acidic soils in Jaldu district and Cheha district in central Ethiopia. Application rates of 0, 2.5, 5, and 7.5 t/ha vermicompost; 0, 2, 4, and 6 t/ha agricultural lime; and 0, 50, 100, and 150 kg/ha NPS fertilizer were applied to acidic soils of the study areas. Soil chemical properties related to acidity were determined using standard laboratory procedures, which indicated low pH, available phosphorus (P), organic carbon (C), total nitrogen (N), total exchangeable bases, and cation exchange capacity, along with high exchangeable acid before planting. After harvesting, agricultural lime improved acidity-related soil conditions, including pH, organic C, available P, and total exchangeable bases, while reducing exchangeable acids in both districts. Vermicompost specifically improved soil organic C and total N in the soil of Jaldu district. The improvement in soil acidity due to liming was greater than that achieved by vermicompost or NPS fertilizer. Wheat yield increased in response to all rates of agricultural lime, vermicompost, and NPS-fertilizer applications. The highest yields of 5.71 t/ha and 4.62 t/ha were obtained with the application of 6 t/ha of agricultural lime in Cheha district and Jaldu district, respectively. The study demonstrated that sustainable agricultural practices soil amendment with agricultural inputs decreases soil acidity and improve wheat grain yields. Locational disparities in soil physical–chemical properties and wheat production with limited amendment options can limit the applicability of the findings from the selected study districts to wider regions. Therefore, investigations over diverse locations, seasons, and wheat varieties are needed to examine the effects on soil fertility and crop yield returns, and the economic viability of using diverse agricultural inputs. Full article

The increasing use of nano-agrochemical formulations in agricultural systems has intensified concerns regarding their impact on soil properties and nutrient dynamics. This study aimed to compare the effects of engineered copper (I) oxide nanoparticles (Cu₂O-ENPs) and engineered copper nanoparticles (Cu-ENPs) on chemical and physical properties, as well as on phosphorus (P) availability, in a volcanic soil (VS). Soil samples were incubated for one day with both types of ENPs at a 1% dose under controlled conditions, and changes in pH, electrical conductivity (EC), organic matter (OM), bioavailable copper (Cu), specific surface area (SSA), pore volume (PV) and pore diameter (PD), among other parameters, were evaluated. Additionally, to determine the impact of Cu-based ENPs on P availability, adsorption–desorption studies were conducted using batch systems in triplicate. The findings revealed that both Cu-based ENPs altered the soil’s chemical and physical properties. Notably, both types of ENPs increased the bioavailability of Cu²⁺, with a more pronounced effect observed for Cu-ENPs (720 ± 4.20 mg kg⁻¹), indicating their higher dissolution rates. This phenomenon was associated with an increase in soil EC. Furthermore, Cu-based ENPs decreased SSA and PV, and PD in VS, with a higher effect for Cu₂O-ENPs (SSA = 10.035 m² g⁻¹, PV = 0.009 cm³ g⁻¹, and PD = 3.608 nm). The application of 1% Cu-based ENPs enhanced the adsorption of P in VS at pH = 4.5 and pH = 5.5, with a greater effect observed for 1% Cu-ENPs than with 1% Cu₂O-ENPs. In contrast, 1% Cu₂O-ENPs retained a higher amount of P in VS than 1% Cu-ENPs. Collectively, the results of this study provide novel insights into the contrasting effects of Cu₂O-ENPs and Cu-ENPs in agricultural soils, underscoring the need for further investigation of ENPs to elucidate the underlying mechanisms and the long-term implications for soil health and agricultural productivity. Full article