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Search Results (1,248)

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Keywords = humic acids

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16 pages, 1612 KB  
Article
Evaluation of the Resource Utilization Potential of Capsicum Residue for Sustainable Industrial Capsaicin Extraction
by Zhifeng Hu, Shijiao Li, Tianxue Yang, Dongyang Li, Xiaowei Wang, Yuxin Chen, Zhe Zhang, Zhiliang Yao, Dayang Yu, Shi Cheng, Yilin Wang and Jiaomei Liu
Sustainability 2025, 17(22), 10303; https://doi.org/10.3390/su172210303 - 18 Nov 2025
Abstract
Capsicum residue generated from industrial capsaicin extraction is rich in nutrients and represents a significant fraction of solid waste in the food processing industry. Despite its potential value, limited efforts have been devoted to its resource recovery, leading to considerable resource loss and [...] Read more.
Capsicum residue generated from industrial capsaicin extraction is rich in nutrients and represents a significant fraction of solid waste in the food processing industry. Despite its potential value, limited efforts have been devoted to its resource recovery, leading to considerable resource loss and environmental burdens. This study systematically evaluates the applicability of existing food waste recycling technologies for capsicum residue and assesses its valorization potential through comprehensive characterization. The results indicate that capsicum residue holds promise as a feedstock for pectin extraction and as a component in animal feed. Regarding anaerobic fermentation for acid production, the maximum volatile fatty acids (VFAs) yield and VFAs/SCOD ratio reached 462.09 mg·L−1 and 3.16%, respectively, suggesting moderate potential for acidogenic conversion but limited suitability for methanogenesis. Fluorescence spectroscopy of dissolved organic matter revealed that microbial humic-like substances (C1) were the dominant fluorophore, accounting for 42.64% of the total fluorescence, followed by terrestrial humic-like (C2, 19.28%), fulvic-like (C3, 19.12%), and tryptophan-like (C4, 18.95%) components. The favorable C/N ratio of amino acids and humic substances supports the feasibility of composting. Additionally, trace levels of residual capsaicin may confer antibacterial benefits and enhance soil fertility, further supporting the potential of capsicum residue as a value-added resource. Full article
(This article belongs to the Special Issue Research on Resource Utilization of Solid Waste)
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23 pages, 3378 KB  
Article
Impact of Particle Size on the Aerobic Decomposition and Fertilizer Efficiency of Corn Cobs: A Sustainable Waste-to-Resource Approach
by Qian Liu, Pengbing Wu, Xingchi Guo, Ying Qu, Junyan Zheng, Yuhe Xing, Zhiyu Dong, Wei Yu, Guoyu Zhang and Xu Zhang
Biology 2025, 14(11), 1610; https://doi.org/10.3390/biology14111610 - 17 Nov 2025
Abstract
The conversion of agricultural residues into high-value organic amendments is fundamental to sustainable farming systems. Corn cobs represent a widely available lignocellulosic resource; however, their rigid structural properties often hinder efficient biodegradation during composting. This study evaluated whether optimizing corn cob particle size [...] Read more.
The conversion of agricultural residues into high-value organic amendments is fundamental to sustainable farming systems. Corn cobs represent a widely available lignocellulosic resource; however, their rigid structural properties often hinder efficient biodegradation during composting. This study evaluated whether optimizing corn cob particle size could improve aerobic composting performance by enhancing humification and compost quality. Corn cobs were ground into three particle sizes (6-mesh, 10-mesh, and 20-mesh) and composted with a commercial microbial inoculant for up to 51 days. Physicochemical properties, humic substance fractions (HSC, HAC, FAC), microbial community dynamics (16S rRNA and ITS sequencing), and maturity indicators were monitored. The 10-mesh treatment (M10) exhibited the most favorable composting outcomes, achieving the greatest degree of humification (HA/FA = 2.85; HAC = 48.30 g/kg) and the most pronounced aromatic condensation in humic acids. M10 also supported a more diverse and metabolically specialized microbial consortium, with notable enrichment of lignocellulose-degrading and humus-forming genera (e.g., Streptomyces, Thermobifida). Consequently, M10 produced the most mature compost, reflected by the highest germination index (93.63%) and the lowest heavy-metal accumulation, meeting agricultural safety standards. Structural equation modeling revealed that particle size influenced humification primarily by modulating microbial community structure (path coefficient = 0.86), highlighting particle size as a key environmental selector in composting systems. Overall, 10-mesh particle size created an optimal aeration–moisture balance that stimulated microbial metabolism, accelerated organic matter degradation, and enhanced stable organic matter formation. These findings demonstrate that corn cob particle size significantly governs composting efficiency and final product quality. Selecting a 10-mesh size presents a practical pretreatment strategy to accelerate biomass turnover and produce safe, nutrient-rich compost, providing an effective approach for sustainable bioconversion of agricultural residues. Full article
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12 pages, 3286 KB  
Article
Sustainable Strategy Using Tung Fruit-Derived Humic Substances–Ferrihydrite for Simultaneous Pollutant Removal and Fertilizer Recovery
by Hao Lin, Yuhuan Su, Chengfeng Liu, Jiayi Tu, Ruilai Liu and Jiapeng Hu
Toxics 2025, 13(11), 974; https://doi.org/10.3390/toxics13110974 - 12 Nov 2025
Viewed by 238
Abstract
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 [...] Read more.
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
(This article belongs to the Section Toxicity Reduction and Environmental Remediation)
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18 pages, 2515 KB  
Article
The Use of Electric-Field Can Effectively Reduce Greenhouse Gas Emissions and Promote Carbon Conversion in Compost
by Xiaoyun Lian, Lingling Chen, Hongmei Zhang, Deguo Kong, Ling Zhou and Weiguo Xu
Fermentation 2025, 11(11), 638; https://doi.org/10.3390/fermentation11110638 - 9 Nov 2025
Viewed by 396
Abstract
This study focused on the effect of electric field intensity on carbon transformation in aerobic composting of biochar–pig manure. Four treatment groups were set up with voltages of 0 V (CK group), 2 V (L group), 4 V (M group), and 5 V [...] Read more.
This study focused on the effect of electric field intensity on carbon transformation in aerobic composting of biochar–pig manure. Four treatment groups were set up with voltages of 0 V (CK group), 2 V (L group), 4 V (M group), and 5 V (H group). The physicochemical properties and carbon forms of the compost were characterized, and how they influence composting was investigated by observing the changes in the functional groups of the compost and the interactions between microorganisms and environmental factors. The results showed that the electric field treatment groups entered the thermophilic phase 2–3 d earlier than the CK group, and the duration of this phase was extended by 3–5 d. The seed germination indices were 95.2%, 106%, 110%, and 121% for the CK, L, M, and H treatment groups, respectively. The DOC content decreased by 11.7%, 11.4%, 16%, and 16.5%. The degradation rates of hemicellulose were 38.6%, 41.1%, 42.7%, and 42.8%, respectively. Those of cellulose were 46.8%, 47.7%, 51.8%, and 54.5%, respectively. Those of lignin were 37.2%, 40.8%, 47.9%, and 53.3%, respectively. Compared to the CK group, the cumulative emissions of CO2 and CH4 in the L, M, and H groups were reduced by 13.8–25% and 47.86–75.76%, respectively, resulting in lower carbon losses. Fourier transform infrared spectroscopy indicated that applying an external electric field induces changes in the functional groups of humic acid, the formation of aromatic functional groups, and the optimization of the maturation process. Compared to the CK group, applying an electric field (L/M/H groups) optimized the microbial communities (especially the Bacteroidota, Chloroflexi, and Acidobacteriota abundances), enriched Proteobacteria and Myxococcota, and regulated the moisture content and C/N ratio. These changes in the electric field treatment groups significantly improved the degradation efficiency of cellulose, lignin, and hemicellulose and reduced greenhouse gas emissions. Full article
(This article belongs to the Section Industrial Fermentation)
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21 pages, 4042 KB  
Article
Transcriptomic and Physiological Insights into the Role of Nano-Silicon Dioxide in Alleviating Salt Stress During Soybean Germination
by Seo-Young Shin, Won-Ho Lee, Byeong Hee Kang, Sreeparna Chowdhury, Da-Yeon Kim, Hyeon-Seok Lee and Bo-Keun Ha
Agriculture 2025, 15(22), 2320; https://doi.org/10.3390/agriculture15222320 - 7 Nov 2025
Viewed by 217
Abstract
Salt stress is a major form of abiotic stress that disrupts soybean germination and early seedling establishment. In this study, physiological, biochemical, and transcriptomic analyses—including germination index, antioxidant enzyme activity, and RNA-seq profiling—were conducted during soybean germination to elucidate early responses to salt [...] Read more.
Salt stress is a major form of abiotic stress that disrupts soybean germination and early seedling establishment. In this study, physiological, biochemical, and transcriptomic analyses—including germination index, antioxidant enzyme activity, and RNA-seq profiling—were conducted during soybean germination to elucidate early responses to salt stress and biostimulant treatment. A preliminary screening of six biostimulants (nanoparticle zinc oxide (NP-ZnO), nanoparticle silicon dioxide (NP-SiO2), silicon dioxide (SiO2), glucose, humic acid, and fulvic acid) revealed NP-SiO2 as the most effective in promoting germination under salt stress. Under 150 mM NaCl, NP-SiO2 increased the germination rate and length of the radicle compared with the control, also enhancing peroxidase and ascorbate peroxidase activities while reducing malondialdehyde accumulation, suggesting alleviation of oxidative stress. RNA sequencing revealed extensive transcriptional reprogramming under salt stress, identifying 4579 differentially expressed genes (DEGs) compared with non-stress conditions, while NP-SiO2 treatment reduced this number to 2734, indicating that NP-SiO2 mitigated the transcriptional disturbance caused by salt stress and stabilized gene expression networks. Cluster analysis showed that growth- and hormone-related genes suppressed by salt stress were restored under NP-SiO2 treatment, whereas stress-responsive genes that were induced by salt were attenuated. Hormone-related DEG analysis revealed that NP-SiO2 down-regulated the overactivation in the abscisic acid, jasmonic acid, and salicylic acid pathways while partially restoring gibberellin, auxin, cytokinin, and brassinosteroid signaling. Overall, NP-SiO2 at 100 mg/L mitigated salt-induced oxidative stress and promoted early soybean growth by fine-tuning physiological and transcriptional responses, representing a promising nano-based biostimulant for enhancing salt tolerance in plants. Full article
(This article belongs to the Special Issue Crop Yield Improvement in Genetic and Biology Breeding)
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19 pages, 2049 KB  
Article
Eco-Friendly Biotechnological Approaches to Enhance Germination Efficiency in Lavandula angustifolia Mill.
by Ioan-Adrian Georgiu, Elena Adriana Ciulca, Giancarla Velicevici, Radu E. Sestras, Monica Boscaiu, Oscar Vicente and Adriana F. Sestras
Horticulturae 2025, 11(11), 1339; https://doi.org/10.3390/horticulturae11111339 - 6 Nov 2025
Viewed by 346
Abstract
The improvement of Lavandula angustifolia Mill. seed germination represents a crucial step towards the development of eco-biotechnological solutions for the sustainable propagation of aromatic plants. This study evaluated the effects of four biostimulant formulations, namely Amino 16 (amino acid-based), Razormin (humic–fulvic complex), Germinoseed [...] Read more.
The improvement of Lavandula angustifolia Mill. seed germination represents a crucial step towards the development of eco-biotechnological solutions for the sustainable propagation of aromatic plants. This study evaluated the effects of four biostimulant formulations, namely Amino 16 (amino acid-based), Razormin (humic–fulvic complex), Germinoseed (phytoextract-based), and Atonik (nitrophenolate), together with a non-treated control, on the germination efficiency and early growth of nine Lavandula genotypes under controlled laboratory conditions. A factorial design (9 × 5) with four replications was applied, and multiple germination indices were calculated. Data were analysed using a two-way ANOVA with genotype and treatment as main factors. Results indicated significant genotype-dependent responses. Amino 16 and Razormin markedly increased germination percentage, speed of emergence, and seedling vigour, achieving up to 100% germination in responsive genotypes such as ‘Ellagance Snow’ and ‘Blue Spear’. Correlation and clustering analyses revealed strong links between seed size, germination rate, and seedling development, suggesting a possible synergistic role of amino and humic substances in stimulating metabolic activation during germination. These findings demonstrate that eco-friendly biostimulants function as effective biotechnological activators of seed physiology, supporting low-input propagation systems and the transition toward a circular green bioeconomy. Full article
(This article belongs to the Section Propagation and Seeds)
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13 pages, 3458 KB  
Article
Red Brick Powder-Based CoFe2O4 Nanocomposites as Heterogeneous Catalysts for Degrading Methylene Blue Through Activating Peroxymonosulfate
by Chuqiao Sha, Fangkui Cheng, Shen Luo, Chao Zhou and Hong Zhang
Sustainability 2025, 17(21), 9886; https://doi.org/10.3390/su17219886 - 5 Nov 2025
Viewed by 249
Abstract
CoFe2O4 loaded onto red brick powder (CoFe2O4@RBP) was synthesized via coprecipitation followed by post-calcination and employed as a heterogeneous catalyst to activate peroxymonosulfate (PMS) for the degradation of methylene blue (MB), thereby valorizing red brick demolition [...] Read more.
CoFe2O4 loaded onto red brick powder (CoFe2O4@RBP) was synthesized via coprecipitation followed by post-calcination and employed as a heterogeneous catalyst to activate peroxymonosulfate (PMS) for the degradation of methylene blue (MB), thereby valorizing red brick demolition waste within a circular economy pathway and aligning the study with sustainability-oriented resource recovery. The effects of pH, PMS concentration, catalyst dosage, and coexisting substances on MB removal were systematically investigated. Complete MB removal was achieved within 30 min, and the apparent rate constant for the CoFe2O4@RBP/PMS system was 0.22 min−1—slightly lower than that of CoFe2O4/PMS—while Co leaching was markedly reduced. The process performed well across a broad pH range (3.0–9.0). EPR and radical-quenching experiments indicate that SO4 and HO• play a minor role, whereas the Co(II)–PMS complex is primarily responsible for MB degradation; accordingly, common coexisting species (SO42−, Cl, NO3, humic acid) exert negligible effects. The catalyst also maintained strong durability across numerous repetitions. These results highlight a cost-efficient route to PMS activation by coupling CoFe2O4 with construction waste-derived supports. Full article
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21 pages, 881 KB  
Article
STR-Uggles: Overcoming Humic Acid Inhibition Using Combined STR & qPCR Kit Chemistries
by Caitlin McDonald, Duncan Taylor and Adrian Linacre
Genes 2025, 16(11), 1326; https://doi.org/10.3390/genes16111326 - 3 Nov 2025
Viewed by 409
Abstract
Background/Objectives: DNA profiling can fail, or produce poor results, when naturally occurring materials are present during the amplification step. This study demonstrates that simple modifications to the reaction setup can overcome this obstacle. PCR inhibition is caused by a range of compounds including [...] Read more.
Background/Objectives: DNA profiling can fail, or produce poor results, when naturally occurring materials are present during the amplification step. This study demonstrates that simple modifications to the reaction setup can overcome this obstacle. PCR inhibition is caused by a range of compounds including haem, humic acid and dyes. Various strategies to overcome this inhibitory effect have been explored, such as improving extraction methods to remove these compounds, diluting samples to reduce inhibitor concentration, or using inhibitor-tolerant DNA polymerases. In this study, we evaluate whether modified setups can help mitigate the effects of humic acid, a common inhibitor that induces various inhibition mechanisms. Methods: We combined the GlobalFiler STR kit with Investigator Quantiplex Pro into a single reaction. Supplementing the amplification GlobalFiler with additional reagents creates altered amplification environments that use additional DNA polymerase and reaction buffer. Results: The modified setups outperformed the standard GlobalFiler protocol, even at the highest concentration of humic acid tested. The STR reactions supplemented with qPCR reagents produced higher-quality profiles with improved allele amplification and an even peak balance, indicating that a dual-DNA polymerase system offers a more robust and inhibitor-tolerant environment for STR amplification. In addition to demonstrating the value of this combined approach, these data provide a comprehensive dataset characterising the impact of increasing humic acid concentrations on profile quality from an ideal DNA input. Conclusions: For PCR inhibitors with similar mechanisms this approach offers broader applicability in forensic casework and a promising step toward more reliable and robust profiling of inhibited samples. Full article
(This article belongs to the Special Issue Novel Insights into Forensic Genetics)
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23 pages, 2274 KB  
Article
Quality Management and Sustainability in the Design of Active Biocomposites: Evaluation of Double-Layer Protein–Polysaccharide Complexes Enriched with Plant Extracts
by Nikola Nowak-Nazarkiewicz, Wiktoria Grzebieniarz, Joanna Tkaczewska, Agnieszka Cholewa-Wójcik, Michał Kopeć, Krzysztof Gondek, Hanna Derechowska and Ewelina Jamróz
Molecules 2025, 30(21), 4259; https://doi.org/10.3390/molecules30214259 - 31 Oct 2025
Viewed by 295
Abstract
Despite promising results, biocomposite research still requires elaboration, particularly with regard to functional properties and applications. In this study, multilayer biocomposites based on gelatin, κ-carrageenan and carboxymethylcellulose were enriched with sage or blackberry extracts. The films were characterized based on their physicochemical traits [...] Read more.
Despite promising results, biocomposite research still requires elaboration, particularly with regard to functional properties and applications. In this study, multilayer biocomposites based on gelatin, κ-carrageenan and carboxymethylcellulose were enriched with sage or blackberry extracts. The films were characterized based on their physicochemical traits and bioactivity for application as active packaging and environmental biodegradation. FTIR confirmed extract integration and strong matrix interactions, while UV-VIS analysis showed efficient UV blocking. Water properties remained acceptable (WVTR ≈ 550 g/m2 × d); solubility decreased for BB (41.73% vs. 53.45% control). Mechanical testing indicated a plasticizing effect: elongation increased (20.00% control; 35.35% BB; 39.29% SAGE), while tensile strength and Young’s modulus decreased. Antioxidant capacity rose (FRAP: 0.38 control, 1.97 BB, 4.48 SAGE µTrolox/mg; DPPH: 6.38% control, 85.68% BB, 78.25% SAGE; MCA: none). During refrigerated storage, antimicrobial effects were most evident on days 6–9. Lipid oxidation peaked for BB (0.92 mg MDA/kg, day 9), while pH was more stable with SAGE. Biodegradation and phytotoxicity confirmed environmental safety and compostability, with increased humic acid carbon in vermicompost. Overall, the results confirm the relevance of modifying biopolymers using green chemistry and highlight their importance for quality management, food safety and sustainable circular economy strategies. Full article
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19 pages, 10161 KB  
Article
A Sustainable Technology Approach to Lettuce (Lactuca sativa L.) Grown Under Greenhouse Condition Through Foliar Application of Various Biostimulants
by Roxana Maria Madjar, Mariana Cristiana Gheorghe and Gina Vasile Scăețeanu
Sustainability 2025, 17(21), 9736; https://doi.org/10.3390/su17219736 - 31 Oct 2025
Viewed by 369
Abstract
Biostimulants play a crucial role in producing high-quality products with increased yields while also positively impacting sustainable agriculture by reducing reliance on chemical fertilizers and promoting soil fertility. In this context, an experiment was developed to evaluate the influence of several commercial foliar [...] Read more.
Biostimulants play a crucial role in producing high-quality products with increased yields while also positively impacting sustainable agriculture by reducing reliance on chemical fertilizers and promoting soil fertility. In this context, an experiment was developed to evaluate the influence of several commercial foliar fertilizers and biostimulants (Cropmax, FullGreen, Nutrigizer, and Rerum) on the yield and quality parameters of lettuce cultivated in a greenhouse system. The tested products have different formulations, with all containing macronutrients and microelements. Cropmax and Rerum also include amino acids, while Nutrigizer 60 2E contains humic acids. The experiment was arranged in a randomized block design and comprised five treatments, with a control and four biostimulants, Cropmax, FullGreen, Nutrigizer, and Rerum, each replicated five times. Foliar treatments were applied four times to the butterhead lettuce variety ‘Analena’, suitable for spring to autumn production. All foliar treatments resulted in an increase in leaf biomass compared to that for the control variant. Notably, foliar fertilization with Rerum increased the yield by 2.19 times compared to that in the control. Quality indices—dry matter, ascorbic acid, and sugar contents—also improved after treatments. The foliar treatments also significantly enhanced key quality indices, with the Rerum variant showing the most pronounced increases in dry matter (24.11%), ascorbic acid (69.75%), and sugar content (26.38%) compared to those for the control. These results demonstrate that foliar application of biostimulants, particularly Rerum, is an effective sustainable technology strategy for significantly enhancing both the yield and nutritional quality of greenhouse-grown lettuce. Full article
(This article belongs to the Special Issue Green Technology and Biological Approaches to Sustainable Agriculture)
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21 pages, 6047 KB  
Article
Metagenomics Insights into the Functional Profiles of Soil Carbon, Nitrogen Under Long-Term Chemical and Humic Acid Urea Application
by Tengfei Guo, Mengyuan Wang, Ke Yue, Peng Luo, Xiao Song, Shaomin Huang, Xinpeng Xu, Qian Zhang, Yulu Chen, Zekun Zhang, Sumiao Su, Shijie Ding, Shuiqing Zhang and Kun Zhou
Agronomy 2025, 15(11), 2535; https://doi.org/10.3390/agronomy15112535 - 30 Oct 2025
Viewed by 475
Abstract
Long-term positioning tests can systematically reveal the evolution characteristics of soil fertility and crop productivity, and reflect the spatiotemporal changes in soil quality and their driving factors. While soil microorganisms mediating nutrient cycling are crucial for maintaining crop productivity and the long-term resilience [...] Read more.
Long-term positioning tests can systematically reveal the evolution characteristics of soil fertility and crop productivity, and reflect the spatiotemporal changes in soil quality and their driving factors. While soil microorganisms mediating nutrient cycling are crucial for maintaining crop productivity and the long-term resilience of agricultural ecosystems, how prolonged use of different fertilization strategies affects their functional capacity remains insufficiently understood. In this study, we applied metagenomic sequencing to investigate how three fertilization treatments, namely (i) N0 receiving only phosphorus (P) and potassium (K) fertilizers, (ii) N250 receiving conventional urea + P and K, and (iii) F250 receiving humic acid urea + P and K, influence soil microbial communities, functional genes related to C and N cycling, and associated soil properties in a long-term field experiment. The F250 treatment significantly increased average annual yields of wheat and maize to 7166.21 kg hm−2 and 8309.96 kg hm−2, respectively. These values were 148.66% and 73.47% higher than those under N0, and 8.22% and 11.64% higher than those under N250. Compared with N0, both N250 and F250 signally augmented soil nitrate, ammonium, total nitrogen (TN), and soil organic carbon (SOC), altered microbial community composition, and enhanced the relative abundance of genes engaged in C fixation and methane oxidation. Both treatments also promoted denitrification and dissimilatory nitrate reduction to ammonium (DNRA). Relative to N250, F250 specifically enriched the beneficial bacterial genus Pedobacter, further increased the abundance of the C fixation gene pccA, and markedly upregulated the DNRA gene nrfA. Soil TN and SOC were identified as the key environmental factors regulating microbial community structure and the functional potential of C and N cycling pathways. Collectively, our findings provide a mechanistic understanding of how long-term application of humic acid urea enhances crop productivity by modulating the genetic potential of soil microorganisms in biogeochemical cycles, offering a biological foundation for optimizing fertilization strategies in sustainable agriculture. Full article
(This article belongs to the Section Soil and Plant Nutrition)
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22 pages, 2592 KB  
Article
UV/TiO2/IO4 Advanced Oxidation of Safranin O: Disentangling Matrix Complexity and Radical-Scavenger Interference
by Meriem Bendjama, Oualid Hamdaoui and Abdulaziz Alghyamah
Catalysts 2025, 15(11), 1022; https://doi.org/10.3390/catal15111022 - 30 Oct 2025
Viewed by 370
Abstract
The effectiveness of periodate-assisted photocatalysis in removing the cationic dye Safranin O (SO) was evaluated using a UV/TiO2/IO4 process operated at room temperature under near-neutral pH conditions. Under base conditions ([IO4] = 0.15 mM, [TiO2 [...] Read more.
The effectiveness of periodate-assisted photocatalysis in removing the cationic dye Safranin O (SO) was evaluated using a UV/TiO2/IO4 process operated at room temperature under near-neutral pH conditions. Under base conditions ([IO4] = 0.15 mM, [TiO2] = 0.4 g/L, [SO] = 10 mg/L), the ternary system achieved a pseudo-first-order rate constant of 0.6212 min−1, outperforming the UV/TiO2 and UV/IO4 processes by approximately 21- and 29-fold, respectively. This yielded a synergy ratio of about 12 compared to the sum of the binary processes. Targeted quenching experiments revealed the operative pathways. Strong inhibition by ascorbic acid and phenol indicates that interfacial holes and OH are key oxidants. Methanol caused a moderate slowdown, consistent with OH and hole scavenging. Benzoquinone and oxalate suppressed removal by intercepting the electron and O2•− pathways, respectively. Dichromate markedly inhibited the process via optical screening and competition for electrons. Azide had little effect, suggesting a minor role for singlet oxygen. Matrix studies showed progressively slower kinetics from deionized water to mineral water to seawater. This was due to halides, sulfate, alkalinity, and TiO2 aggregation driven by ionic strength. Additional tests confirmed that the dominant modulators of performance were humic acid (site fouling and light screening), chloride and sulfate (radical speciation and surface effects), nitrite (near-diffusion radical quenching), and bicarbonate at pH 8.3 (conversion of OH to CO3•−). Nonionic surfactants (Tween 80, Triton X-100) also depressed SO removal through micellar sequestration and competitive adsorption on TiO2. The study confirms the potential of UV/TiO2/IO4 as a tunable AOP capable of delivering rapid and reliable dye degradation under a wide range of water quality conditions. The mechanistic mapping unifies two roles for IO4, an electron acceptor that inhibits recombination and a photochemical precursor of iodine centered and OH radicals and connect these roles to the observed synergy and to the trend across deionized water, mineral water, and seawater. The scavenger outcomes assign the main oxidant flux to holes and OH radicals with a contributory electron or O2•− branch from IO4 reduction. Full article
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33 pages, 4345 KB  
Article
Multiyear Assessment of Biofertilizer Application on ‘Gala’ Apple Orchards: Impacts on Soil Fertility, Leaf Mineral Content, and Agronomic Performance
by Susana Ferreira, Catarina Lopes, Marta Gonçalves, Margarida Rodrigues, Francisco Martinho and Miguel Leão de Sousa
Plants 2025, 14(21), 3319; https://doi.org/10.3390/plants14213319 - 30 Oct 2025
Viewed by 811
Abstract
Biofertilizers are sustainable alternatives to mineral fertilizers in perennial crops, reducing the need for mineral inputs. This five-year field study evaluated three biofertilizers—Mycoshell® (Glomus spp. + humic/fulvic acids), Kiplant iNmass® (Azospirillum brasilense, Bacillus megaterium, and Saccharomyces cerevisiae [...] Read more.
Biofertilizers are sustainable alternatives to mineral fertilizers in perennial crops, reducing the need for mineral inputs. This five-year field study evaluated three biofertilizers—Mycoshell® (Glomus spp. + humic/fulvic acids), Kiplant iNmass® (Azospirillum brasilense, Bacillus megaterium, and Saccharomyces cerevisiae), and Kiplant All-Grip® (Bacillus megaterium and Pseudomonas spp.)—at different dosages alongside two mineral fertilizer regimes, T100 (full recommended dose) and T70 (70% of T100, alone or combined with biofertilizers), in an apple orchard under Mediterranean conditions. Biofertilizers maintained or increased soil nutrient availability by 5–15% and leaf N, P, K, Mg, and Zn concentrations by 5–12% compared with T100. Trees under biofertilizers, particularly Myc2 and Myc4, exhibited greater shoot growth (up to 30.4 m/year), trunk cross-sectional area (TCSA: 11.9 cm2 in 2022), and canopy volume (2.21 m3), representing 10–20% increases. Selected biofertilizer treatments produced 6–7.5 kg/tree, 130–145 g average fruit weight, 66–74 mm diameter, 13.9–18.7 °Brix, and 13–18% dry matter, maintaining >90% of yield and fruit size relative to T100, with more balanced medium- and large-sized fruit distribution. Principal Component Analysis explained 66–72% of soil and leaf nutrient variance, confirming their multivariate impact. Overall, biofertilizers applied at recommended doses and timings can partially replace mineral fertilizers, sustaining productivity and quality, enhancing nutrient availability, and supporting long-term orchard sustainability. While climate remains the main driver of annual production, these findings provide evidence for integrating biofertilizers into environmentally friendly fertilization strategies. Full article
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18 pages, 4441 KB  
Article
Effects of Humic Acids, Freeze–Thaw and Oxidative Aging on the Adsorption of Cd(II) by the Derived Cuttlebones: Performance and Mechanism
by Zhaohui He, De Wang, Lin Shi, Hongqi Xie, Yanqing Xiong and Di Zhang
Sustainability 2025, 17(21), 9628; https://doi.org/10.3390/su17219628 - 29 Oct 2025
Viewed by 277
Abstract
Currently, few studies have revealed the comprehensive effects of environmental organic matter, freeze–thaw and oxidative aging on the adsorption performance of cadmium (Cd(II)), which is essential for the sustainable stability evaluation of the adsorbent. Herein, we observed that humic acids (HAs) extracted from [...] Read more.
Currently, few studies have revealed the comprehensive effects of environmental organic matter, freeze–thaw and oxidative aging on the adsorption performance of cadmium (Cd(II)), which is essential for the sustainable stability evaluation of the adsorbent. Herein, we observed that humic acids (HAs) extracted from different soils inhibited the adsorption performance of Cd(II) onto the cuttlebone-derived samples by occupying the different major adsorption active sites of the adsorbent, and the lower cadmium-complexation ability of HAs would increase the occupation of adsorption sites. The freeze–thaw process increased the pore size and volume of the cuttlebone-derived samples, while oxidative aging enhanced the specific surface area and introduced additional C–O/C=O groups. These changes promoted the adsorption performance of Cd(II) in the cuttlebone-derived samples after freeze–thaw or oxidative aging. Additionally, the resistances of cuttlebone-based adsorbents to HAs, freeze–thaw, and oxidative aging were elucidated and optimized by simple alkali boiling or carbonization treatment. Furthermore, the adsorption capacities of Cd(II) by samples in the natural cadmium-contaminated river ranged from 548.99 mg g−1 to 571.55 mg g−1, which are higher values than those of most reported adsorbents. Therefore, this work provides an important experimental basis for the practical application and sustainable design of adsorbents under real environmental conditions. Full article
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Article
Ozonation of Reverse Osmosis Concentrate from Municipal Wastewater Reclamation Processes: Ozone Demand, Molecular Weight Distribution, UV/Fluorescence Characteristics, and Microalgal Growth Potential
by Yuchang Chi, Zibin Xu and Nan Huang
Sustainability 2025, 17(21), 9564; https://doi.org/10.3390/su17219564 - 28 Oct 2025
Viewed by 401
Abstract
To address the challenge of treating reverse osmosis concentrate (ROC) in municipal wastewater reclamation processes, this study systematically investigated changes in ozone demand, organic compound molecular weight distribution, UV/fluorescence characteristics, and microalgal growth potential during ozone treatment of ROC. The ROC contained fast-reacting [...] Read more.
To address the challenge of treating reverse osmosis concentrate (ROC) in municipal wastewater reclamation processes, this study systematically investigated changes in ozone demand, organic compound molecular weight distribution, UV/fluorescence characteristics, and microalgal growth potential during ozone treatment of ROC. The ROC contained fast-reacting substances and had an instantaneous ozone demand of 6.3 mg/L. The chemical oxygen demand (COD) and total organic carbon were partially removed, and the COD/five-day biochemical oxygen demand ratio increased slightly during the ozonation process. The molecular weight components shifted considerably during ozonation: the 300 Da–1000 Da components became dominant (51.6–72.3%), while the 1000 Da–4000 Da and <300 Da components were partially or completely removed. The maximum absorbance of the ROC peaked at 270 nm. At an ozone dosage of 84 mg/L, the UV254 and UV270 removal rates reached 76.9% and 86.5%, respectively. The three-dimensional fluorescence spectra showed that ozone effectively removed tryptophan-type aromatic proteins, fulvic acid-type substances, aromatic proteins, soluble microbial metabolites, and humic acid-type substances from the concentrate (84.6–88.9%), but only removed a minimal amount of the tyrosine-type aromatic protein (7.4%). The UV254 at different molecular weights and the fluorescence area integrals across regions declined rapidly initially, then slowed gradually, correlating with the rapid reaction of UV/fluorescence chromophore-containing substances in ROC. Studies on microalgal growth potential indicate that ozonation increased the maximum algal density (K) in ROC (48.9–91.7%), while ozone/coagulation effectively reduced K (35.1–76.6%). This occurs because ozone converts organic phosphonate antiscalants in ROC into more readily absorbable inorganic phosphorus, whereas ozone/coagulation effectively removes total phosphorus from water. These results can guide the safe disposal of ROC and facilitate sustainable reclamation of municipal wastewater. Full article
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