Search Results (1,616)

Cadmium (Cd) accumulation in agricultural soils from prolonged phosphate fertilizer application threatens food safety in Southeast Asia, yet the combined performance of vermicompost (VC), biochar (BC), and Azolla microphylla for Cd immobilization remains poorly characterized. We evaluated their individual and combined effects in a Cd-spiked Korat soil (100 mg kg⁻¹ Cd as Cd(NO₃)₂) under controlled laboratory conditions. A completely randomized pot experiment with eight treatment combinations (four amendment regimes × two Azolla levels, n = 3) was incubated for five weeks; total and exchangeable Cd, selected soil properties, and Eisenia fetida growth were assessed before and after treatment. The combined of soil, cadmium vermicompost and biochar (SCVB) + Azolla treatment reduced total Cd by 41.13% and exchangeable Cd by 81.02%, significantly outperforming single amendments, while raising organic matter to 6.31% and nitrogen (N), phosphorus (P), and potassium (K) availability. Principal component analysis (PCA) explained >98% of the variance and separated SCVB clearly from the unamended control along soil-quality and Cd axes. Strong negative correlations between Cd and fertility indicators (r = −0.86 to −0.96) indicated coupled immobilization and fertility recovery. A 5-day acute earthworm bioassay confirmed reduced soil toxicity under SCVB + Azolla, with growth inhibition reduced from 55.9% to 23.6%, mortality reduced from 26.7% to 10%, and tissue Cd accumulation reduced from 44.08 to 25.17 mg kg⁻¹ (42.9% reduction). The integrated VC + BC + Azolla system offers a cost-effective amendment-assisted Cd immobilization strategy for tropical soils, pending field validation. Full article

Biochar has emerged as a sustainable additive in concrete production, offering potential for improved concrete performance and waste valorization. An experimental investigation was conducted using wood waste biochar as a partial cement replacement at 0%, 2%, 4%, and 6% by weight. Compressive strength (CS) and split tensile strength (STS) were determined at 7 and 28 days, while flexural strength (FS) was determined at 28 days. The experimental results demonstrated that 2 to 4% biochar replacement enhanced CS by 9.67% and FS by 15.40%, while STS showed optimal improvement at 2% replacement by 6.24%. To extend these findings across diverse feedstocks and mix designs, a comprehensive database of 318 mixes incorporating 13 biochar types was compiled from literature to develop machine learning (ML) models for predicting all three strength properties simultaneously. Random Forest (RF) and Gradient Boosting (GBR) algorithms were optimized using nested 5-fold cross-validation and compared against a Ridge regression baseline. The optimized RF model (n_estimators = 1000) achieved a nested cross-validated R² of 0.817 ± 0.072 and a 32.5% reduction in RMSE compared to the baseline, with testing R² values of 0.894 for CS, 0.828 for FS, and 0.537 for STS. (SHapley Additive exPlanations) (SHAP) analysis identified cement content, coarse aggregate (CA) content, and biochar dosage as the most influential features. Biochar effect curves, based on the most reliable datasets (rice husk, n = 69; wood, n = 52), demonstrated that rice husk biochar consistently enhanced all three strength properties, while wood biochar showed superior performance for FS and STS. Experimental validation using wood waste biochar confirmed that model predictions closely matched measured strengths, with 90% prediction intervals reliably encompassing experimental values. The developed models offer a practical decision-support tool for sustainable concrete mix design, significantly reducing experimental effort while providing evidence-based guidance for biochar feedstock selection and dosage optimization, keeping the cement usage at a minimum. Full article

Soil salinization is one of the most severe forms of land degradation in arid and semi-arid regions, posing substantial threats to agroecosystem stability and food security. In this study, saline–alkali soil collected from the Wuding River Basin in Yulin, Shaanxi Province was used to construct a three-factor amendment system comprising superabsorbent polymers (SAP), biochar, and humic acid. A systematic assessment was conducted to elucidate their combined effects on soil water–salt transport and crop growth. Results from one-dimensional constant-head infiltration experiments using indoor soil columns demonstrated that the application of amendments significantly increased cumulative infiltration and improved the uniformity of wetting-front advancement. Specifically, the treatments regulated the redistribution of salts within the soil profile; while surface salinity reduction varied, the leaching efficiency was significantly enhanced in the A2B2C2 treatment. Soil bulk density (BD) showed dynamic fluctuations during the growth cycle, peaking at 1.628 cm⁻³ during the branching stage, while high-rate biochar (A3) reduced BD by up to 13.64% compared to the control by the initial flowering stage. Fitting results based on the Philip and Kostiakov models further indicated that the combined amendment strategy—particularly the A2B2C2 treatment (30 kg/ha SAP, 15,000 kg/ha biochar, and 600 kg/ha humic acid)—markedly enhanced both the initial infiltration rate and the steady infiltration capacity. Field experiments corroborated the indoor findings: plant height and dry biomass of Melilotus officinalis (L.)Lam. were significantly higher under amendment treatments than in the control, driven by improved water availability, mitigated salt stress, and enhanced soil structure. Single-factor and multi-factor interaction analyses revealed that SAP exerted pronounced effects during early growth stages, whereas biochar and humic acid contributed more substantially during the middle to late stages through sustained regulatory functions. Collectively, the results demonstrate that the combined application of SAP, biochar, and humic acid improves the water–salt regime of saline–alkali soils through a coupled “water–salt–structure–plant” mechanism, ultimately enhancing crop productivity. This study provides both theoretical insights and practical guidance for the amelioration of saline–alkali soils. Full article

Reclaiming saline–alkaline soil is critical for food security and land expansion. While paddy rice is the key pioneer crop for remediation, the soil fertility–yield relationship remains poorly understood. To optimize remediation strategies, this study evaluated soil fertility under 16 agronomic treatments—integrating irrigation quality, fertilizer regimes, and soil amendments—across three rice growth stages (tillering, heading, and maturity) in the Yellow River Delta using the minimum data set (MDS), integrated soil fertility index (SFI), and random forest models. Saline water irrigation increased soil salinity by 24.6%, while straw returning and desulfurization gypsum reduced salinity by 18.3% and 22.7%, respectively. Straw, biochar, and desulfurization gypsum significantly influenced soil organic carbon (SOC), total nitrogen (TN), inorganic nitrogen (NH₄⁺-N, NO₃⁻-N), and available phosphorus (AP), with effects varying across growth stages. Growth-stage-specific MDS indicators were significantly correlated with SFI based on the total data set (R² = 0.70, 0.65, and 0.81, p < 0.01), and stage-specific SFI was significantly positively related to rice yield. Notably, heading-stage SFI, although relatively low, explained the highest yield variance (R² = 0.51, p < 0.01) and prediction accuracy (%IncMSE = 25.22), especially under conventional NPK combined with full straw incorporation and desulfurization gypsum. These findings highlight the critical role of heading-stage soil fertility in regulating rice production, providing a targeted nutrient management blueprint for saline–alkaline paddy fields in the Yellow River Delta. Overall, this study offers a reliable scientific template to enhance yield and promote sustainable agriculture in comparable saline–alkaline paddy fields globally. Full article

The Colombian Caribbean is a strategic area for avocado production, not only because of its favorable climatic conditions, but also because of the availability of varieties with a high content of compounds of industrial interest. The Creole-Antillean avocado grown in Montes de María represents a significant source of raw material with potential for processing, both because of the lipid fraction of its pulp and the chemical composition of its seed. However, the use of this resource has been limited by low technology incorporation and poor coordination of agro-industrial chains that would allow its valorization beyond fresh consumption. In view of this situation, the design of a plant for the simultaneous production of oil and biochar is proposed, with the aim of migrating from a linear model to a comprehensive biomass valorization scheme. The study analyzes the performance of the process from a thermodynamic perspective, applying an exergy analysis that allows for the evaluation of the quality of the energy used and the quantification of irreversibilities at each stage. The results indicate that the highest exergy destruction occurs during seed washing (12.37%), oil extraction and centrifugation (19.71%), distillation and condensation (20.64%), and pyrolysis with by-product separation (28.72%). Although the seed washing stage showed high exergy efficiency (99.81%) when integrated into biochar production, stage 12 recorded a significant loss of 2438.52 MJ/h, associated with the non-use of the volatile gases generated in pyrolysis. Overall, the exergy efficiency of the system reached 30.07%, reflecting the high thermodynamic demands involved in transforming the seed into a high-value product such as biochar. This type of assessment not only identifies critical points of exergy destruction, but also establishes technical bases for optimizing energy consumption, reducing losses, and moving towards a more efficient and sustainable process. Full article

Agricultural crop residue burning is a major driver of seasonal PM2.5 pollution and greenhouse gas (GHG) emissions in Northern Thailand. This study quantified GHG emissions from the open burning of rice, maize, and sugarcane residues across six provinces (Chiang Mai, Mae Hong Son, Lampang, Uttaradit, Nakhon Sawan, and Kamphaeng Phet) from 2019 to 2024 using the 2006 IPCC emission methodology. Spatiotemporal patterns of fire hotspots were characterized using MODIS and VIIRS satellite data, combined with kernel density estimation (KDE) and land-use classification in ArcGIS Pro. Total non-CO₂ GHG emissions (CH₄ and N₂O, expressed as CO₂-eq using GWP100 from IPCC AR5) over the six years totaled 2,599,551 tCO₂-eq, with major rice contributing the largest share (35%), followed by sugarcane (24%), second rice (21%), and maize (20%). Nakhon Sawan was the leading emitter (41%), reflecting its extensive rice and sugarcane cultivation. Pearson correlation analysis revealed consistently positive relationships between daily fire hotspot counts and PM2.5 concentrations (r = 0.30–0.84), with the strongest correlations observed in Mae Hong Son, where basin topography traps pollutants. Time-series analysis confirmed pronounced seasonal PM2.5 peaks that exceeded Thailand’s 24-h NAAQS limit (37.5 μg/m³) by 7–9 times in severe years. Biochar production via pyrolysis was evaluated as a zero-burning alternative, with an estimated annual carbon sequestration potential of 2.3–3.5 million tCO₂-eq, substantially exceeding emissions from open burning. These findings indicate that crop-residue valorization options—including biochar production, composting, and biochar co-compost—could theoretically offset agricultural GHG emissions and reduce field-burning PM2.5 emissions in Northern Thailand. However, the realized mitigation will depend on (i) verification of biochar long-term stability in tropical Thai soils through dedicated in situ trials, (ii) economic incentives that offset biochar production costs of approximately 1500–3500 THB per tonne, and (iii) integration within a policy mix that combines burning bans, mechanization support, and farmer extension services. Without these enabling conditions, biochar should be regarded as a future-perspective option rather than an immediately deployable solution. Full article

This study examined the effectiveness of using biochar from the tanning industry as a silicon carrier to reduce trace element toxicity and improve plant nutrition in soil–plant systems. Silicon-enriched biochar was produced from chromium-free leather waste and applied in 21-day pot trials with cucumber. It contained 11.6 ± 2.3% SiO₂ and effectively served as a slow-release silicon carrier. Optimal plant growth and nutrient uptake were achieved with the application of 100% silicon without additional NPK fertilizers, demonstrating a strong positive correlation with essential trace elements such as copper and iron. Importantly, silicon fertilization significantly reduced the uptake of toxic metals such as Al, Cd, and Ti, underscoring the potential of silicon-enriched biochar for phytoremediation and sustainable crop production. Using silicon-enriched biochar from industrial leather waste thus provides a novel, sustainable strategy to improve soil fertility and plant health while repurposing waste. Future work should include long-term field trials and examine species-specific responses and management practices to scale up this approach for enhanced crop resilience. Full article

Fish-processing residues represent a significant environmental challenge due to their high moisture and nitrogen contents, which favor greenhouse gas (GHG) emissions during degradation. This study evaluated how different waste management strategies affect GHG emissions from fish waste, including conventional composting (Bulk), composting amended with biochar (BulkBioch), burial with soil (S), and burial with soil plus sawdust (BulkS). Daily emissions of CH₄, N₂O, and CO₂ were monitored, and cumulative emissions were modeled using generalized additive models. Composting treatments (Bulk and BulkBioch) released higher CO₂, suggesting greater microbial degradation, while burial treatments developed earlier anaerobic conditions with reduced decomposition efficiency. Bulk showed the highest cumulative CH₄ and CO₂ emissions, whereas N₂O fluxes were greater in burial methods, reaching 2.18 g N₂O kg⁻¹ TS in S. Biochar addition was associated with 15% and 10% lower CH₄ and N₂O emissions, respectively, and earlier stabilization of CH4 emissions. In global warming potential, BulkBioch presented the lowest climate impact (305 g CO₂-eq kg⁻¹ fish), followed by Bulk (338 g CO₂-eq kg⁻¹), whereas BulkS reached up to 599 g CO₂-eq kg⁻¹. The use of bulking agents in burial resulted in lower CH₄ buildup and greater nutrient retention. Overall, combining bulking agents and biochar may represent a promising strategy to mitigate GHG emissions while supporting nutrient conservation. Full article

To promote the sustainable management of marine aquaculture waste, this study investigated the effect of corn stover biochar (300 °C, 400 °C, and 500 °C) on the mesophilic anaerobic digestion (37 ± 1 °C) of particulate matter from seawater aquaculture wastewater. Batch experiments evaluated biochar’s effects on methane production, microbial succession, and antibiotic resistance genes (ARGs), and the correlation between ARG abundance and microbial taxa. Biochar addition significantly enhanced biogas production and shortened the lag phase. During 60 h fermentation, the optimal treatment achieved a methane yield of 291 mL, which was 164.55% higher than the control. Metagenomic sequencing revealed that biochar altered microbial community structure and ARG profiles, reducing the 11 most prevalent ARG types. Glycopeptide resistance genes showed the greatest reduction (15.02%). Correlation analysis identified Enterococcus, Peptostreptococcus, and Clostridium as major ARG hosts, accounting for 64.78–69.81% of total ARG abundance in the control and 68.14–76.17% in the biochar-amended group, confirming that Firmicutes are key potential ARG carriers in marine aquaculture particulate waste. From the perspective of sustainable development, biochar addition improves energy recovery from aquaculture waste and mitigates ARG dissemination risk. This study provides practical guidance for material selection and process optimization in sustainable aquaculture biogas projects, supporting the transition toward a circular bioeconomy. Full article

Biochar and zeolite are promising additives for improving composting; however, their effects during the co-composting of agricultural waste have not yet been sufficiently studied. This study evaluated their influence on the composting of green onion residues and chicken manure under psychrophilic conditions on a pilot scale using 200 kg piles. Three treatments were evaluated: a control, 5% biochar, and 2% zeolite. Both amendments increased the maximum composting temperature by approximately 3 °C and improved the germination index, with increases of around 10% for biochar and 26% for zeolite compared to the control. Biochar increased the relative abundance of the amoA gene, associated with ammonia oxidation and nitrification, suggesting greater biochemical potential for nitrification. During maturation, zeolite reduced pH and electrical conductivity, indicating greater compost stability. In fast-growing crops, compost from zeolite treatment did not significantly affect plant growth when applied alone, but improvements were observed when combined with synthetic fertilizer. Overall, both additives improved composting performance and compost quality, with zeolite showing the most consistent effects. Full article

The mechanical recycling of mono-material biaxially oriented polypropylene (BOPP) packaging films produces recycled polypropylene (rPP) with degraded properties, limiting its use in higher-performance applications. This study investigates rPP reinforcement with 6–12 µm microcellulose fibres (MCFs, 2–10 pbw) and microcellulose-derived biochar (BC, 5–20 pbw), characterized by DSC, TGA/DTG, MVR/MFR, temperature-dependent rheology, mechanical testing and water contact angle (WCA) measurements. Both fillers acted as heterogeneous nucleating agents, shifting crystallization by up to 4 °C and increasing crystallinity by 2–4%. MCF introduced an additional low-temperature degradation step, whereas BC increased onset and peak degradation temperatures by up to 20 °C and increased char yield. Low MCF loadings increased MVR/MFR by 20–25% and reduced melt viscosity, while BC decreased flow indices by up to 50% and stiffened the melt. Tensile and flexural moduli increased by 15–25% with MCF and 40–50% with BC, with a stiffness–toughness trade-off at the highest BC contents. MCF reduced the water contact angle to 63.0° at 10 pbw, while BC increased it to 108.1° at 20 pbw, indicating opposite effects on surface wettability. Converting a single cellulosic feedstock into fibrous or carbonised fillers enables bio-based upgrading of rPP, in line with circular economy principles. Full article

Mitigating methane (CH₄) emissions from paddy fields without compromising yield remains a critical challenge for sustainable agriculture, primarily due to trade-offs between emission reduction and nutrient availability. Biochar-based fertilizer (BF), which integrates biochar with mineral nutrients, may address this constraint by regulating carbon and nitrogen availability. This study evaluated the effects of biochar-based fertilization on CH₄ emissions and rice productivity. A one-season field experiment was conducted in Hydragric Anthrosols with four treatments: no fertilization (control), conventional chemical fertilization (CF), integrated application of biochar-based and chemical fertilizers (CBF), and biochar-based fertilizer alone (BF). Methane fluxes were monitored alongside soil physicochemical properties and the abundances of key functional microbial genes. Compared with CF, BF significantly reduced cumulative CH₄ emissions by 23.24% while maintaining comparable rice yield, resulting in a 28.67% reduction in yield-scaled CH₄ emissions. Biochar-based fertilization decreased dissolved organic carbon availability, buffered NH₄⁺-N concentrations, and increased soil pH. These changes shifted the microbial balance of CH₄ cycling, suppressing methanogenesis and enhancing methane oxidation, as reflected by a lower mcrA/pmoA ratio. Structural equation modeling indicated that CH₄ mitigation was jointly driven by reduced methanogenic activity and enhanced methane oxidation. Overall, biochar-based fertilization regulates soil chemical and microbial processes to mitigate CH₄ emissions without yield penalties, demonstrating strong potential as a scalable and field-applicable strategy for low-carbon rice production. Full article

Wheat (Triticum aestivum L.) productivity in saline soils is often constrained by nutrient imbalance, water scarcity, and ionic stress, particularly in arid regions such as the Nile Delta of Egypt. This study evaluated the combined effects of biochar (2.4 t ha⁻¹) and 1% foliar seaweed extract under varying nitrogen application levels on soil chemical properties, wheat growth, yield, nutrient uptake, and N-use efficiency indices over two consecutive winter seasons (2023/2024 and 2024/2025). A factorial field experiment with three replicates was conducted using four nitrogen rates: 0%, 50%, 75%, and 100% of the recommended application (168 kg N ha⁻¹), combined with four treatments: control, seaweed extract, biochar, and their integration. Combined analysis showed that the highest grain yield was obtained under full nitrogen with biochar and seaweed extract (7085.75 kg ha⁻¹), although this was not significantly different from several integrated treatments, particularly those involving 75% nitrogen with amendments. The 75% N + biochar + seaweed extract treatment achieved comparable yield while significantly improving nitrogen-use efficiency indices, including recovery efficiency, agronomic efficiency, and partial factor productivity. Biochar and seaweed extract improved soil organic carbon, cation exchange capacity, and nutrient availability, while electrical conductivity was not significantly affected. These results indicate that nitrogen input can be reduced by up to 25% without yield loss when combined with these amendments, while enhancing nutrient-use efficiency. However, conclusions regarding salinity stress mitigation remain indirect due to the absence of physiological measurements. Overall, this integrated approach supports more sustainable wheat production in saline soils. Full article

Cadmium (Cd) contamination in rice paddies poses serious threats to food safety. This study investigated the effects of bamboo biochar, a microbial agent, and their combination on Cd accumulation, soil properties, and rhizosphere microbial communities in the rice cultivar ‘Ning 47’ (Oryza sativa L.) under Cd stress (20 mg·kg⁻¹). Cd stress significantly reduced plant height, root length, and yield. However, combined treatment with biochar and microbial agent (CdMB) effectively mitigated these effects, reducing Cd content in grains, stems, and roots by 85.98%, 88.66%, and 73.89%, respectively, compared to Cd treatment alone. The CdMB treatment also significantly increased soil organic matter and total nitrogen content while decreasing soil Cd levels by 88.38%. Network analysis identified Flavisolibacter as a keystone taxon under CdMB treatment, indicating enhanced microbial network stability. This also provides a theoretical reference for the management of heavy metal contamination in agricultural soils. By reducing grain Cd contamination and enhancing soil health, this integrated approach addresses key targets of the United Nations Sustainable Development Goals, including SDG 2 (Zero Hunger), SDG 3 (Good Health and Well-being), and SDG 15 (Life on Land). Full article

This review synthesizes recent advances in the characterization of eco-friendly cement composites, focusing on hydration kinetics, microstructural evolution, and mechanical durability. Advanced techniques—from isothermal calorimetry to nanoindentation—enable decoding of reaction pathways, mix optimization, and long-term performance prediction. The analysis covers supplementary cementitious materials (fly ash, slag, silica fume), geopolymers, bio-based additives (SNSs, biochar, CNCs, lignosulfonates), and microbially induced calcite precipitation (MICP). For each category, key mechanisms are identified, property effects quantified, and microstructural correlations established. SCMs achieve pore refinement and enhanced durability through long-term pozzolanic reactions. Geopolymers exhibit exceptional thermal stability (800–1000 °C) and acid resistance. Fly ash-based geopolymers exhibit chloride diffusion coefficients 1–2 orders of magnitude lower than ordinary Portland cement (OPC), though slag-based systems show more moderate improvements due to their different pore structure and higher calcium content. Bio-based additives enable accelerated hydration (SNSs), internal curing and CO₂ sequestration (biochar), pore refinement (CNCs), workability enhancement (lignosulfonates), and autonomous crack healing (MICP). Multi-scale characterization is essential for establishing robust structure–property relationships. The review concludes that properly optimized eco-friendly cement composites offer viable pathways toward sustainable construction with reduced carbon footprint, enhanced durability, and extended service life. This review is novel in its systematic comparison of hydration kinetics, microstructural evolution, and mechanical performance across three distinct classes of eco-friendly additives (SCMs, geopolymers, and bio-based materials), with particular emphasis on the complementarity of advanced characterization techniques—an aspect that has received limited attention in previous reviews. Full article