Search Results (309)

Integrated multi-trophic aquaculture (IMTA) has emerged as an ecological intensification strategy capable of enhancing nutrient utilization and improving environmental stability in mariculture systems, yet the microbial mechanisms driving nutrient transformations remain insufficiently understood. This study investigated how culture mode (IMTA vs. monoculture) shape water quality, sediment microbial communities, and nutrient cycling processes in a shrimp–sea urchin system by combining water-quality monitoring, nutrient analysis, 16S rRNA high-throughput sequencing, and redundancy analysis. IMTA significantly increased turbidity, chlorophyll-a, phosphate, ammonium, and nitrite compared with monoculture, while physico-chemical parameters remained stable. Sediment microbiota in IMTA exhibited substantially higher alpha diversity and showed a clear compositional separation from monoculture communities. At the genus level, IMTA sediments were enriched in Vibrio, Motilimonas, and Ruegeria, distinguishing them from monoculture systems. At the phylum level, IMTA was characterized by increased abundances of Proteobacteria and Bacteroidota, accompanied by a marked decline in Spirochaetota. Functional predictions indicated that microbial communities were predominantly characterized by pathways related to amino acid and carbohydrate metabolism, as well as nutrient remineralization. RDA and correlation analyses further identified turbidity, chlorophyll-a, phosphate, ammonium, and nitrite as the principal drivers of microbial divergence. Overall, the findings demonstrate that IMTA reshapes sediment microbial communities toward more efficient nutrient-processing assemblages, thereby promoting active nitrogen and phosphorus transformations and improving biogeochemical functioning relative to monoculture. These results provide mechanistic insight into how IMTA supports nutrient recycling and environmental sustainability in modern mariculture systems. Full article

Biomass ashes represent a promising secondary phosphorus (P) source, yet their agronomic performance depends on feedstock origin, processing, and crop-specific interactions. This study evaluated the P fertilizer efficacy of raw and processed biomass ashes derived from cereal straw and paludiculture biomass, compared with triple superphosphate (TSP), using two sequential greenhouse pot experiments with maize, amaranth, and blue lupine. Processed ash products, particularly compacted ashes and ash–straw mixtures, increased plant biomass and P uptake to levels comparable to or exceeding those achieved with TSP. The cumulative P uptake of the three crops reached up to 250–300 mg pot⁻¹ under processed ash treatments, exceeding the uptake under TSP (≈150–180 mg pot⁻¹) and the unfertilized control (≤80 mg pot⁻¹). However, crop-specific differences were observed: amaranth benefited most from the ash products, whereas combinations of ashes with lupine were less favorable. Beside acting as a P source, processed biomass ashes also increased soil pH by about 0.5 units, improved soil aggregation by increasing macroaggregates (>2 mm) to up to 20% compared with only about 7% in TSP and the control, and promoted favorable shifts in Hedley P fractions. Soil enzyme activities were governed primarily by crop species, with amaranth stimulating phosphatase activity the most. Further research should aim to refine crop-specific application strategies for processed biomass ashes and to elucidate their impacts on soil structure and P dynamics. Full article

Efficient phosphorus recovery is of great significance for sustainable wastewater management and resource recycling. While chemical precipitation is widely used, its effectiveness under complex multi-factor conditions remains challenging to predict and optimize. This study compiled a multidimensional dataset from recent experimental literature, encompassing key operational parameters (reaction time, temperature, pH, stirring speed) and dosages of three metal precipitants (Al³⁺, Ca²⁺, Fe³⁺) to systematically evaluate and benchmark phosphorus recovery performance across these distinct systems, six machine learning algorithms—Random Forest (RF), eXtreme Gradient Boosting (XGBoost), Gaussian Process Regression (GPR), Elastic Net, Artificial Neural Network (ANN), and Partial Least Squares Regression (PLSR)—were developed and cross-validated. Among them, the GPR model exhibited superior predictive accuracy and robustness. ($R^2$ = 0.69, $RMSE$ = 0.54). Beyond achieving high-fidelity predictions, this study advances the field by integrating interpretability analysis with Shapley Additive Explanations (SHAP) and Partial Dependence Plots (PDP). These analyses identified distinct controlling factors across systems: reaction time and pH for aluminum, Ca²⁺ dosage and alkalinity for calcium, and phosphorus loading with stirring speed for iron. The revealed factor-specific mechanisms and synergistic interactions (e.g., among pH, metal dose, and mixing intensity) provide actionable insights that transcend black-box prediction. This work presents an interpretable Machine Learning (ML) framework that offers both theoretical insights and practical guidance for optimizing phosphorus recovery in multi-metal systems and enabling precise control in wastewater treatment operations. Full article

This study investigated the effects of different Effective Microorganism (EM) inoculation concentrations (0%, 0.5%, 2%, 5%, 10%, 15%) on the co-composting of Auricularia heimuer residue with chicken manure and the subsequent growth of maize. The aim was to enhance composting efficiency and promote maize productivity. Results showed that EM addition, particularly at medium concentrations, significantly accelerated the composting process by shortening the heating phase and prolonging the thermophilic period, with the 10% treatment reaching >50 °C by day 2. The 5–10% EM treatments markedly promoted the degradation of cellulose and hemicellulose, and enhanced key enzyme activities (e.g., cellulase and hemicellulase) during composting and maize growth stages. Regarding soil nutrients, the 5% EM treatment led to the most balanced increases in total nitrogen (TN), total phosphorus (TP), and total potassium (TK) contents, with rises of 58.7%, 47.8%, and 130.4%, respectively, during the seedling stage. For maize yield, this treatment enhanced total grain weight, hundred-grain weight, and root activity by 25.7%, 30.9%, and 53.2%, respectively, while also increasing dry matter and root weight. Redundancy and correlation analyses indicated strong positive relationships among root activity, soil TN, cellulase activity, and final yield. In conclusion, EM inoculation at 5–10% optimizes the composting process, improves substrate quality and nutrient supply, and promotes maize root development and yield, with 5% EM offering the most comprehensive benefits. This study provides a practical approach for agricultural waste recycling and sustainable maize cultivation. Full article

China possesses abundant stover resources, and promoting the recycling of stover instead of open burning is a crucial measure for reducing carbon emissions and protecting the atmospheric environment. This study systematically investigated the effects of four stover management strategies—stover removal (CK), direct stover return (SD), stover biochar return (BC), and a combined half-stover half-biochar return (SB)—on soil physicochemical properties, enzyme activities, and microbial communities in the meadow brown soil of Northeast China. The results demonstrated that BC treatment significantly increased the soil total carbon (TC), total nitrogen (TN), total phosphorus (TP), available phosphorus (AP), and available potassium (AK) contents. SB treatment showed the most pronounced enhancement in TP. Regarding enzyme activities, Compared with CK, SD significantly increased the activity of N-acetyl -β -D-glucosaminase (NAG). Furthermore, all stover return practices significantly enhanced bacterial community diversity but suppressed fungal diversity. SB treatment resulted in the greatest improvement in bacterial richness and diversity. Beta diversity analysis revealed that SD and SB significantly altered the soil microbial community structure, whereas BC had a minimal impact. In conclusion, the combined application of stover and biochar (SB) exhibited the most consistent and beneficial outcomes across multiple soil health indicators, highlighting its potential as an effective integrated strategy for enhancing soil fertility, promoting carbon sequestration, and sustaining the health of the meadow brown soil ecosystem in Northeast China. Full article

The effect of nitrogen (N) deposition on soil organic carbon (SOC) and the underlying mechanisms in grassland ecosystems remain a topic of debate. Moreover, previous research has primarily concentrated on interaction between carbon (C) and N cycles in response to N deposition, with less attention paid to how N-induced phosphorus (P) deficits impact SOC sequestration. To further investigate whether soil microbial stoichiometry influences SOC sequestration under N enrichment, we conducted a field experiment involving N and P additions. The soil properties, nutrients within plant leaves and microbial biomass, and the potential activity of eco-enzymes related to microbial nutrient acquisition were measured. Results showed that SOC did not significantly change with N addition, and SOC significantly increased with addition of N and P together, which suggested that the SOC was depleted with N addition. Soil available phosphorus and microbial biomass phosphorus (MBP) did not significantly decrease alongside N addition, which suggested that microbes alleviated P limitation. Microbial metabolic limitation analysis showed microbial P limitation was enhanced by N10 treatment. At the same time, microbial P limitation enhanced microbial C limitation. Consequently, microbes also required more C as an energy resource to invest in enzyme production. Microbial P and C limitations were both significantly negatively correlated with SOC. Results from SEM analysis also showed that the MBC:MBP ratio was significantly negatively correlated with SOC. These results support the idea that consumer-driven nutrient recycling shapes the dynamics of SOC. Therefore, nitrogen deposition-induced MBC:MBP imbalance may regulate SOC in alpine grassland ecosystems. Full article

Background/Objective: Sewage sludge (biosolids) is increasingly reused as a fertilizer to recycle nutrients and close material cycles; however, concerns persist regarding antibiotics and antimicrobial resistance. This study evaluated the agronomic safety and microbiological integrity of biosolid fertilization in soybean and maize systems, with particular attention to grain quality and food safety. Methods: Soybean and maize were cultivated in greenhouse microcosms under biosolid or mineral fertilization. Soil, roots, shoots, and grains were analyzed for antibiotic residues using LC–MS/MS and antibiotic-resistant bacteria (ARB) using culture-based assays. Minimum inhibitory concentrations for isolates from grains were compared with clinical breakpoints to verify phenotypic susceptibility. Multivariate analyses (PCA) integrating real-time antibiotic concentrations and updated resistance indicators were performed using centered and scaled data. Results: Fluoroquinolones were the predominant residues introduced by biosolids and exhibited consistent time-dependent declines across all treatments, although low concentrations remained detectable at 90 d in several soil–fertilizer–crop combinations. Tetracyclines, macrolides, and sulfonamides showed similar decreasing trends, with planted soils displaying faster dissipation than bulk control soils. Biosolid fertilization increased shoot biomass by 1.5–2.3-fold and nitrogen, phosphorus, and potassium uptake by 30–60% without impairing soybean nodulation or nitrogenase function. ARB was observed in all soils, including mineral and plant-free controls, indicating a natural background resistome. Ciprofloxacin-resistant isolates were detected in one simple sampling point, and MDR proportions were transient (67%), returning to their background levels by 45–90 days. PCA showed that crop presence, not fertilizer type, was the primary driver of microbial ordination, and that antibiotic concentrations and resistance indicators were only weakly aligned, indicating a limited selective pressure. No antibiotic residues or phenotypically resistant bacteria were detected in the soybean or maize grains. Conclusions: Updated residue, resistance, and multivariate data confirmed that biosolids did not induce, amplify, or transfer antibiotic resistance and maintained complete grain safety. Properly treated biosolids function as safe, agronomically beneficial fertilizers aligned with One Health goals, enhancing crop productivity without compromising food quality or increasing antimicrobial resistance. Full article

The limited availability of phosphorus (P) in soil poses a critical constraint on agricultural productivity, and sustainable P fertilization practices are of great importance for crop production. In this study, we developed a novel dual-function granular material (RMG) derived from red mud, a waste residue from the aluminum industry. This material is capable of adsorbing P in P-rich soils and releasing P in P-deficient soils, thereby enabling the sustainable use of red mud and P fertilizer. The influences of RMG on the migration and transformation of P in soil were investigated. Application of RMG significantly increased the critical threshold for P leaching, thereby effectively mitigating P loss. In the initial stage of leaching, P in the leachate was present predominantly as particulate phosphorus, whereas molybdate-reactive P became the dominant form in later stages. With increasing RMG dosage, the pH of the leachate rose while the total phosphorus concentration declined, indicating that alkaline components in RMG promoted the adsorption and precipitation of phosphates in soil. The release behavior of P from P-enriched RMG was also examined. The results showed that the total soil P content increased progressively with higher RMG dosage and longer cultivation duration. Elevated temperature and soil moisture content were found to enhance the release and migration of P from RMG into the soil. SEM-EDS analyses revealed that released components (e.g., Ca²⁺ and Fe³⁺) from RMG formed relatively stable complexes with free phosphates. Moreover, adsorption of P onto the RMG surface further facilitated its migration and transformation within the soil. The research findings provide valuable insights for the simultaneous pollution remediation and resource utilization of red mud and phosphorus. Full article

The Upper Permian marine shale of the inter-platform basin in the Nanpanjiang Basin are rich in organic matter, widely distributed, and relatively thick, indicating abundant resource potential for hydrocarbon exploration. To clarify the sedimentary condition and the variability of reservoir properties, the paleo-environment was reconstructed by using geochemical, mineralogical, rock-property, and pore-structure data. Building on a lithofacies classification, the development patterns of different shale lithofacies were revealed. Reservoir characteristics among lithofacies were compared using scanning electron microscopy (SEM), nuclear magnetic resonance (NMR), and low-temperature Nuclear Magnetic Resonance Cryoporometry (NMRC) experiments. A fractal analysis was performed based on NMR and NMRC data to quantify pore-scale heterogeneity, calculate fractal dimensions (D₁, D₂, and D_c), and evaluate the complexity of pore systems across lithofacies. Correlation analysis and redundancy analysis were applied to further explore the controlling factors of reservoir heterogeneity. The results showed that organic-rich shale in the Permian Linghao Formation occurred mainly in the 1st Member, with average total organic carbon (TOC) content of 2.57%, and the lower part of the 3rd Member (average TOC content 2.88%). In the 1st Member, high-carbon shale was deposited under humid conditions with intense weathering, abundant fine-grained clastic input from basin margins, strongly reducing (anoxic) bottom waters, vigorous phosphorus recycling, and moderate to low primary productivity. Using TOC and mineral composition, seven shale lithofacies were identified in the Linghao Formation, and their development patterns were established based on depositional paleo-environment characteristics and evolution. In the 1st Member, organic-rich shale was dominated by mixed lithofacies with moderate to high TOC. The paleo-environment exerted a primary control on reservoir properties, gas content, pore structure, and heterogeneity. The high-carbon lithofacies had the most favorable rock properties—higher porosity, greater pore volume, and higher gas content—and contained a larger proportion of well-developed organic pores. Fractal analysis revealed that seepage pores exhibited greater structural complexity than adsorption-related pores, with the high-carbon lithofacies showing the highest overall fractal dimensions and thus the strongest heterogeneity. Across the formation, higher clay content and TOC were the primary drivers of increased pore-scale heterogeneity, whereas greater feldspar and quartz contents tended to diminish it. Carbonates exerted a minor effect. Heterogeneity in adsorption pores exerted the strongest influence on differences among lithofacies. These results highlighted the utility of fractal analysis in quantitatively linking shale mineralogy and organic content to multiscale heterogeneity in inter-platform basin settings. Full article

Advanced phosphorus (P) recycling from wastewater is critical for improving nutrient circularity and reducing soil pollution associated with the direct application of sewage sludge in agriculture. However, few studies evaluate the long-term environmental and economic trade-offs between recycled P products and raw sewage sludge application. This study compares struvite, vivianite, and dicalcium phosphate (CaP) as P alternatives to sludge to mitigate heavy metal accumulation in Spanish agricultural soils. Using data from 27,835 plots, heavy metal accumulation was simulated over 50- and 100-year fertilisation scenarios. The results indicate that continuous sludge application leads to widespread exceedances of zinc, copper, and cadmium, especially in alkaline soils, whereas substitution with recycled products can substantially reduce these risks. Vivianite balances P recycling and costs, CaP offers the best environmental performance but with higher investment, and struvite suits smaller regions prioritising environmental safety. Economic analysis favours advanced recycling over sludge, especially considering externalities such as soil remediation costs. Despite limitations, our findings emphasise the importance of integrating environmental externalities into economic assessments and the value of advanced P recycling for sustainable soil management. Full article

Phosphate tailings (PTs) are typical industrial byproducts that can rapidly neutralize soil acidity. However, their acid-neutralizing efficacy, long-term application optimization mechanisms, and high-yield regulation pathways for crops remain unclear. This study conducted a corn-potato crop rotation field trial on acidic soils, investigating the effect of different PT application rates (T: CK, 0 t·ha⁻¹; PTs-1, 6 t·ha⁻¹; PTs-2, 9 t·ha⁻¹; PTs-3, 15 t·ha⁻¹) in a multiple cropping system (C: late autumn potatoes (LAP)-early spring potatoes (ESP)-summer maize (SM)). The results showed that two consecutive applications of 9 t·ha⁻¹ of PTs produced optimal results, increasing the LAP yield by 12.82% and the soil quality by 76.51%, while improving the ESP soil quality by 46.21%. The higher yield was mainly attributed to a significant increase in the soil pH (0.72–1.58 units) and enhanced chemical and biological properties (higher exchangeable calcium (ExCa), exchangeable magnesium (ExMg), the total exchangeable salt base ion (TEB), and catalase (CAT) and urease (UE) content and lower soil exchangeable acidity (EA), exchangeable hydrogen ion (ExH), and exchangeable aluminum (ExAl) levels). Notably, a synchronized increase in the total phosphorus (TP) and total potassium (TK) during LAP cultivation, combined with simultaneous growth of TP, available nitrogen (AN), and available phosphorus (AP) during ESP cultivation, and a significant increase in TP and AP during SM cultivation, effectively promoted crop yield. Furthermore, continuous PT application significantly enriched phosphorus (P)-soluble functional bacteria, such as Actinomycetes and Chloroflexota, and enhanced the stability of bacterial-fungal cross-boundary networks. In summary, optimal acidity levels and favorable soil texture improved soil quality, consequently increasing corn and potato yields. This study reveals for the first time that PTs can substantially increase crop production via a synergistic mechanism involving acid-base balance, structural improvement, and microbial activation. Not only does this provide a novel strategy for rapidly improving acidic soils, but it also establishes a solid theoretical and technical foundation for utilizing PT resources. Full article

With the rapid increase in solid waste generated worldwide, sustainable approaches for the recovery of resources considering environmental protection are required. As one of the emerging strategies in recent years, biochar has shown great potential due to its high carbon stabilization, adjustable porosity and tunability. This review focuses on the critical assessment of the available technologies for biochar upgrading, with a specific objective of biochar physicochemical functionality improvement and critical materials recovery in line with circular economy targets. We systematically review physicochemical activation methodologies, functionalizations and leaching approaches, accounting for their effects on surface area, porosity and functional group chemistry. Particular attention is paid to the dual functionality of upgraded biochar (i) as a catalyst support for thermochemical processes and (ii) as a medium for the recycling of essential nutrients (e.g., phosphorus, potassium, magnesium, calcium). It is evidenced that customized activation can further improve its adsorption and catalytic efficiency as well as promote near-total nutrition extraction. This review positions advanced biochar as an enabling multipurpose technology across sustainable material production, nutrient cycling and waste valorization in the circular bioeconomy. Full article

Phosphate pollution caused by human activities has become a pressing environmental issue, leading to eutrophication and severe ecological risks. In this study, artificial humic acid (HA) and fulvic acid (FA) were synthesized from tung fruit and glucose, respectively, and further composited with ferrihydrite (Fh) to prepare HA/Fh and FA/Fh adsorbents for phosphate removal. The structural and morphological characteristics of the composites were confirmed by SEM, XRD, FTIR, and XPS analyses, which indicated successful complexation of HA or FA with Fh through ligand exchange and surface interactions. Batch adsorption experiments revealed that HA/Fh and FA/Fh exhibited significantly enhanced adsorption capacities compared to pristine Fh, with maximum Langmuir adsorption capacities of 33.67 mg g⁻¹ and 37.06 mg g⁻¹, respectively. The adsorption behavior was well described by the pseudo-second-order kinetic model and the Langmuir isotherm, suggesting a chemisorption-dominated process involving ligand exchange between surface –OH groups of Fh and phosphate ions, supplemented by electrostatic attraction. Coexisting ion studies demonstrated that Cl⁻ and SO₄²⁻ slightly promoted phosphate adsorption, while NO₃⁻ and CO₃²⁻ strongly inhibited it, highlighting the competition of multivalent anions with phosphate for Fe³⁺ active sites. Importantly, the phosphate-enriched adsorbents can be directly recycled as phosphorus fertilizers, providing a sustainable pathway for both environmental remediation and phosphorus resource recovery. Full article

Hungary faces increasing water challenges, including frequent droughts and a growing dependence on irrigation, which necessitate alternative water sources for agriculture. This study evaluated the use of saline aquaculture effluent—characterized by elevated sodium (Na⁺) and chloride (Cl⁻) concentrations—as an irrigation resource for forage sorghum (Sorghum bicolor L.) over four consecutive growing seasons. Three hybrids (‘GK Áron’, ‘GK Balázs’, and ‘GK Erik’) were tested under five irrigation regimes, including freshwater and aquaculture effluent applied via drip irrigation at weekly doses of 30 mm and 45 mm, alongside a non-irrigated control. Effluent irrigation at 30 mm weekly increased biomass yield by up to 61% and enhanced nitrogen uptake by 22% compared to the control. Soil electrical conductivity (EC) values remained below 475 µS/cm, with effluent treatments showing lower EC than non-irrigated plots. The effluent water also supported the recycling of nutrients, especially nitrogen and phosphorus. Unlike conventional saline water, aquaculture effluent contains organic compounds and microbial activity that may improve nutrient mobilization and uptake. Our results highlight how we can reuse aquaculture wastewater in irrigated crop production. The results demonstrate that moderate effluent irrigation (30 mm/week) can optimize crop water use while maintaining soil health, offering a viable strategy for forage sorghum production in water-limited environments. Full article

Energy consumption and environmental pollution pose significant challenges to sustainable development. This study develops a comprehensive coupled framework model that advances the quantitative integration of carbon (C), nitrogen (N), and phosphorus (P) cycles driven by multiple anthropogenic pollution sources. This paper used Panjin city as a case study to analyze the dynamic changes and interconnections among C, N, and P. Results indicated that net anthropogenic carbon inputs (NAI_C) increased by 33% from 2016–2020, while net anthropogenic nitrogen inputs (NAI_N) and net anthropogenic phosphorus inputs (NAI_P) decreased by 14% and 28%, respectively. The primary driver of NAI_C was energy consumption, while wetlands were the dominant carbon sequestration sink. Agricultural production was identified as the primary source of NAI_N and NAI_P, and approximately 4.5% of NAI_N and 2.9% of NAI_P were discharged into receiving water bodies. We demonstrate that human activities and natural processes exhibit dual attributes, producing positive and negative environmental effects. The increase in carbon emissions drives economic growth and industrial restructuring; however, the enhanced economic capacity also strengthens the ability to mitigate pollution through environmental protection measures. Similarly, natural ecosystems, including forests and grasslands, contribute to carbon sequestration and the release of non-point source pollution. The comprehensive environmental impact assessment of C, N, and P revealed that the comprehensive environmental index for Panjin city exhibited an improved trend. The factors of energy structure, energy efficiency, and economic scale promoted NAI_C growth, with the economic scale factor alone accounting for 93% of the total increment. Environmental efficiency factor and population size factor were the primary drivers in reducing NAI_N and NAI_P discharges into the receiving water bodies. We propose a novel management model, ecological restoration, clean energy utilization, resource recycling, and pollution source reduction to achieve systemic governance of C, N, and P inputs. Full article