Soil Degradation Research Articles

Temperature Dependence of Aerated Turbine Lubricating Oil Degradation from a Lab-Scale Test Rig

Temperature Dependence of Aerated Turbine Lubricating Oil Degradation from a Lab-Scale Test Rig

Does higher ratio of wheat straw addition decrease PAHs degradation in PAHs-contaminated paddy soils and PAHs concentrations in rice?

There are considerable studies focusing on impacts of straw returning on PAHs degradation and bioavailability in PAHs-contaminated upland soils, while similar research in paddy soils is limited. Incubation experiments and pot trials were conducted to study effects of straw returning on PAHs degradation in paddy soils and PAHs accumulation in rice, respectively. There are threshold effects of straw returning on PAHs degradation in PAHs-contaminated paddy soils. The inflection point of PAHs degrading was recorded under 0.8 % wheat straw treatment (conventional (CS) and pretreated wheat straw (PS)), which increased PAHs degradation by 18.13–32.36 %. The lowest PAHs concentrations in rice were recorded under 1 % straw (CS and PS) treatment, which was attributed to the highest PAHs degradation in rhizosphere soils. Compared to CS treatment, PS treatment significantly (p < 0.05) increased PAHs degradation by 7.93–10.28 % and PAHs concentrations in rice by 12.38–45.87 % due to that increasing dissolved organic carbon (DOC) enhanced PAHs concentrations in porewater of rhizosphere soils. Higher diversity enhanced the metabolic pathways and function genes to degrade PAHs by improving bacterial phenotypes and biochemical processes under 1 % wheat straw and PS treatment. The present study firstly demonstrated that the effects of straw returning on PAHs degradation in PAHs-contaminated paddy soils and PAHs concentrations in rice depended on amount and methods of straw returning.

The inclusion of clay minerals accelerates biocrust formation and potentially boosts carbon storage capabilities

Biocrusts, prevalent in desert areas, play a pivotal role in mitigating soil degradation, shaping a common natural landscape. However, amidst climate change and human activities, biocrust coverage is encountering the risk of degradation. The restoration of degraded biocrusts and the construction of artificial ones are regarded as promising technologies for combating soil degradation. Although clay minerals are a crucial abiotic factor in biocrust formation and are directly influence their development and succession, they have not gained widespread attention. The aim of this study was to investigate the mechanism of action of clay minerals in biocrusts. Various quantities of sepiolite were amalgamated with cyanobacteria—Microcoleus vaginatus (ratios of 1:0, 1:10, 1:20, 1:50, 1:100; cyanobacteria dry weight to sepiolite weight), to construct artificial biocrusts and observe the formation and development of them. The results showed that the addition of small quantities of sepiolite (ratios of 1:10 and 1:20) not only facilitated the accumulation of cyanobacterial biomass (1.47–1.86 times) and exopolysacchrides (EPS) (1.73–2.58 times) compared to the control (ratio of 1:0), but also notably enhanced the accumulation of total carbon, total organic carbon, and microbial biomass carbon, highlighting its potential in enhancing the carbon sequestration capabilities of biocrusts. Scanning electron microscope (SEM) analysis revealed that sepiolite serves as a “receiver and bridge” within the biocrust structure, enhancing its compactness and stability, thereby fostering the growth of cyanobacteria and facilitating nutrient transport. Further, Fourier Transform Infrared (FTIR) and X-Ray Photoelectron Spectroscopy (XPS) analysis reviewed changes in some functional groups of EPS and sepiolite after mixing, validating that EPS can function as a “binder” to unify particles. Our findings demonstrate that the incorporation of clay minerals can facilitate biocrust formation, presenting a practical and economical approach, and providing a novel perspective for constructing artificial biocrusts and rehabilitating degraded desert soils.

A slow-release reduction material of Escherichia sp. F1 coupled with micron iron powder achieves the remediation of trichloroethylene-contaminated soil

Trichloroethylene (TCE) is a prevalent organic pollutant found in soil. The oxide passivation layer on the surface of micron iron powder inhibits the release of its reducing components, leading to ineffective reduction and purification of TCE in soil. To enhance TCE degradation, a slow-release reduction material "Escherichia sp. F1-micron iron powder" was developed. A novel iron-reducing bacterium, Escherichia sp. F1, was isolated from soil contaminated with chlorinated hydrocarbons. This bacterium demonstrated a sustained iron reduction capability, achieving a reduction rate of 38.7% for Fe(Ⅲ) within 15 days. Genome sequencing revealed that strain F1 harbors 53 functional iron reduction genes and 2 dehalogenation genes. Single-factor experiments identified the optimal conditions for TCE degradation in soil using the coupling material: glucose concentration at 40 mmol/kg, soil water content at 50%, and bacterial inoculum at 1% (v:w). Under these optimal conditions, the coupled material achieved 86.86% degradation of TCE in soil within 28 days. Further analysis using X-ray photoelectron spectroscopy of micron iron powder, soil Fe(Ⅱ) concentration, and soil physicochemical properties demonstrated that the addition of strain F1 to the soil could disrupt the passivation layer of iron oxide on the surface of micron iron powder, promoting the exposure of its reactive sites and internal reducing active components. This resulted in an in situ self-actuated activation of passivated micron iron powder, leading to an improved removal rate and complete dechlorination of TCE in the soil. Soil microbial high-throughput sequencing revealed that the addition of strain F1 regulated the soil bacterial community, significantly enriching of Escherichia-Shigella species associated with iron-reducing functions. This enrichment facilitated the degradation of TCE in the soil through coupling materials. The functional material plays a crucial role in achieving green treatment and risk control of sites contaminated with chlorinated organic pollutants.

Enhanced degradation of crude oil by immobilized bacterial consortium through eliminating microbial flocculation towards crude oil

Microbial degradation is considered an effective and sustainable technique for the remediation of oily sludge; thus, the acquisition of crude oil-degrading bacteria is crucial for effective bioremediation. This study introduces a novel domestication-enrichment-isolation (DEI) strategy to isolate crude oil-degrading bacteria from oily sludge. Two strains, Rhodococcus rhodochrous JS-24 (R.rh) and Gordonia cholesterolivorans JS-13 (G.ch), demonstrated the highest degradation rates of 53.7% and 34.6%, respectively, within 7 days. While no synergistic effect was observed with their combined use in free bacterial consortia, and the overall degradation rate decreased to 51.9 %, which was weaker than that of R. rh treatment alone. The decrease in degradation rate is attributed to microbial flocculation towards crude oil: most droplets of crude oil were encapsulated into spherical aggregations by G. ch, thereby hindering the contact and degradation of droplets by R. rh. In contrast, immobilization technology significantly enhanced crude oil degradation by eliminating this flocculation effect. The immobilized bacterial consortium achieved a 95.5% degradation rate, representing the highest degradation rate reported for bacterial consortia. This study reveals for the first time that the side effects of bioflocculation on crude oil degradation and provides guidance for the construction of bacterial consortium.

Sustainable Development of Agro-Based Industries and Agricultural Practices: An Analytical Study of Rajasthan

Background: Agriculture plays a pivotal role in Rajasthan's economy, supporting a significant portion of the population. However, the sector faces numerous challenges, including water scarcity, soil degradation, and climate change impacts. This study investigates the sustainable development of agro-based industries and agricultural practices in Rajasthan, analyzing current practices, challenges, and potential solutions. Materials and Methods: The research employed a mixed-methods approach, combining qualitative interviews and focus group discussions with a quantitative survey of 500 participants across various districts of Rajasthan. Data were collected on agricultural practices, challenges faced by farmers, and perspectives on sustainable development. Statistical analysis was performed using SPSS, while qualitative data were analyzed through thematic analysis. Results: The study revealed a blend of traditional (68% using rainwater harvesting) and modern (42% adopting precision farming) agricultural practices. Water scarcity emerged as the most critical challenge, reported by 85% of farmers. Sustainable strategies showed promising results, with organic farming increasing income by 20% and water-efficient irrigation reducing water usage by 40%. Agro-based industries, particularly food processing and textiles, contributed significantly to the state's economy. Conclusion: The findings underscore the need for integrated approaches to address water scarcity, promote sustainable farming practices, strengthen agro-based industries, and enhance farmers' access to markets and credit facilities. Policy recommendations include prioritizing water management, climate change adaptation, and farmer education to ensure a sustainable and resilient agricultural future for Rajasthan

Plant Agrobiodiversity, Agricultural and Phytosanitary Practices of Market Garden Crops in the Centre‐East Region of Burkina Faso

ABSTRACTIntroductionIn West Africa, market gardeners use various agricultural practices to increase yields. However, many of these practices do not comply with agroecological standards and cause intoxication, pollution, soil degradation and biodiversity loss. This study characterizes the plant agrobiodiversity of market garden crops grown during the rainy season and the agricultural and phytosanitary practices used for their management.Materials and MethodsThe study was carried out in Burkina Faso. Plant agrobiodiversity was assessed in 100 market gardens. Agricultural and phytosanitary practices were characterized using semi‐structured interviews. A Sankey diagram was used to highlight the relationships among market garden crops, bioaggressors and diseases. Principal component analyses were applied to highlight the agricultural and phytosanitary practices used.ResultsThe results revealed rich agrobiodiversity, including 16 market garden crops, 15 local agroforestry species, 17 planted species and 37 weed species. The main market garden crops grown in the rainy season were cabbage (20.30%), lettuce (16.62%), tomato (11.69%), and amaranth (10.15%). The most frequent agroforestry species were Azadirachta indica (18.20%) and Mangifera indica (15.03%). The most common weeds were Eleusine indica (11.02%) and Cyperus reduncus (9.70%). Eleven pests were identified, and the most frequently recorded were caterpillars (39.06%). Sixteen diseases were reported, the most common being leaf yellowing (15.67%) and leaf wilt (11.67%). Numerous market gardeners use mineral fertilizers such as Yaramila (NPK 23‐10‐5), NPK (14‐23‐14), urea (46.00% nitrogen), and liquid fertilizer as well as compost and organic manure. The most common agricultural practice was crop rotation (79.00%). To protect crops, 89.00% of producers used synthetic chemical pesticides in an uncontrolled manner, most of which are purchased on the local market. Only 11.00% of the market gardeners practiced the natural phytosanitary treatments.ConclusionThis study provides important information that can be used for the sustainable management of market gardens. Agroecological standards should be popularized to ensure food security for market garden crops.

Multiomic analysis of genes related to oil traits in legumes provide insights into lipid metabolism and oil richness in soybean

Soybean (Glycine max) and common bean (Phaseolus vulgaris) diverged approximately 19 million years ago. While these species share a whole-genome duplication (WGD), the Glycine lineage experienced a second, independent WGD. Despite the significance of these WGDs, their impact on gene families related to oil-traits remains poorly understood. Here, we report an in-depth investigation of oil-related gene families in soybean, common bean, and twenty-eight other legume species. We adopted a systematic approach that included a total of 605 RNAseq samples for transcriptome and co-expression analyse s, identification of orthologous groups, gene duplication modes and evolutionary rates, and family expansions and contractions. We curated a list of oil candidate genes and found that 91.5% of the families containing these genes expanded in soybean in comparison to common bean. Notably, we observed an expansion of triacylglycerol (TAG) biosynthesis (∼3:1) and an erosion of TAG degradation (∼1.4:1) families in soybean in comparison to common bean. In addition, TAG degradation genes were two-fold more expressed in common bean than in soybean, suggesting that oil degradation is also important for the sharply contrasting seed oil contents in these species. We found 17 transcription factor hub genes that are likely regulators of lipid metabolism. Finally, we inferred expanded and contracted families and correlated these patterns with oil content found in different legume species. In summary, our results do not only shed light on the evolution of oil metabolism genes in soybean, but also present multifactorial evidence supporting the prioritization of promising candidate genes that, if experimentally validated, could accelerate the development of high-oil soybean varieties.

Synergistic use of cattle bile, compost and fertilizer amendments in enhancing the bioremediation of hydrocarbon-contaminated soils

This study investigated the degradation of hydrocarbon-contaminated soil using compost, NPK 20:10:10 fertilizer, and cattle bile as biostimulants. In this study, 1000 g of homogenized contaminated soil was amended with 10.50 g of NPK fertilizer and 107.50 g of compost to achieve a nitrogen concentration of 0.2%. To establish a 0.4% nitrogen concentration, 23.90 g of NPK fertilizer, 243.54 g of compost, and 2 ml of cattle bile were used. These amendments were applied in various combinations to create the following microcosm treatments: A, B, C, D, A2, B2, C2, D2, and a control. The microcosms, along with the control were incubated for 6 weeks in triplicate. Throughout this period, several parameters were monitored every two weeks, including pH, nitrogen (N), potassium (K), phosphorus (P), moisture content, organic carbon, organic matter, total heterotrophic bacterial count (THBC), and total petroleum hydrocarbon (TPH) concentration. The results showed significant differences (p < 0.05) in TPH content across the microcosms during the four sampling periods. By the end of the 6-week incubation, the TPH residual concentration varied between 1.58 mg/kg and 20.61 mg/kg, corresponding to degradation rates of 98.43% and 79.58%, respectively, from an initial TPH concentration of 100.91 mg/kg. Microcosm B2 demonstrated the highest hydrocarbon removal efficiency (98.43%), while the control showed the lowest efficiency. The order of degradation efficiency among the microcosms was B2 > B (94.89%) > C (94.64%) > A (94.13%) > D2 (93.62%) > A2 (93.51%) > C2 (92.45%) > D (91.44%). The study also found that pH and nitrogen levels were related to the reduction in hydrocarbon content. Microcosms with a 0.4% nitrogen concentration showed a higher rate of nitrogen consumption compared to those with a 0.2% concentration. Additionally, changes in pH were observed as hydrocarbon degradation progressed. This study further applied cluster analysis, Bayesian statistics, and multiple linear regression to evaluate the effects of treatments on soil quality over time. Cluster analysis showed increasing dissimilarity between merged clusters, while Bayesian analysis revealed positive trends in parameter estimates in Weeks 2 and 4. Regression analysis indicated significant impacts of Weeks 2, 4, and 6 on Week 0, with F-statistics of 8.475 (p = 0.016), 9.804 (p = 0.004), and 3.759 (p = 0.037), though multicollinearity reduced the predictive power of individual coefficients. Overall, Microcosm B2 emerged as the most effective treatment option. The findings suggest that biostimulation using a combination of moisture, compost, NPK fertilizer, and cattle bile is an effective approach to achieving high efficiency in TPH degradation in hydrocarbon-contaminated soils.

Optimizing mechanical and environmental degradation performance of polybutylene adipate terephthalate by adjusting polyvinyl alcohol content

Biodegradable plastics offer a promising alternative to traditional plastics in agriculture, particularly where rapid and controlled degradation is required. This study investigates the properties and degradation behavior of blends of Polybutylene Adipate Terephthalate (PBAT) and Polyvinyl Alcohol (PVA). Mechanical testing revealed that incorporating PVA significantly enhanced both tensile and flexural strengths. For example, pure PBAT had a tensile strength of 14.51 MPa, while the 20PBAT/80PVA blend achieved 53.48 MPa. However, higher PVA content led to reduced elongation at break and fracture toughness. Water immersion tests showed that PVA dissolution and PBAT degradation caused notable reductions in mechanical properties after 5 days, with blends containing 80 % PVA exhibiting an 80.1 % weight loss, and the 40PBAT/60PVA blends showing a 41.75 % weight loss after 30 days. Soil degradation experiments confirmed that the degradation rate increased with higher PVA content. These results highlight the superior degradation performance of PBAT/PVA blends and demonstrate that adjusting the PVA content effectively modulates both degradation rates and mechanical properties. This offers valuable insights for the development of environmentally friendly materials.

Communicating about soil biodiversity: insights from science editorials and future recommendations

Given the urgency of the global soil degradation crisis, soil scientists must communicate the importance of soil as being part of nature and the critical need for conserving soil biodiversity. Drawing on a thematic analysis of editorials related to soil conservation and management, we analyzed common themes, key messages, and frames that authors used to advocate for change. Soil biodiversity was referred to in 8 of the 11 editorials, but it was less emphasized and discussed in less detail than messages centered around food production, water resources, and climate change. Editorials structured arguments around economic development, scientific and technical uncertainty, and morality and ethics. We believe future editorials should apply other persuasive frames including social progress, public accountability, and working-towards-compromise when advocating for soil biodiversity conservation. Soil ecologists can improve communications about soil biodiversity by (1) identifying an audience and selecting relevant key messages, (2) strategically applying a persuasive frame, and (3) amplifying diverse voices with a consistent message. We provide a guide for developing essays that encourages soil ecologists to shape discourse, advance policy priorities, and enable non-soil ecologists to communicate about soil biodiversity conservation.

Sustainable soil management practices provide additional benefit for energy use efficiency

In light of recent fluctuations in energy prices, there has been a growing emphasis on energy efficiency within the agricultural sector. At the same time, ongoing soil degradation in intensive agricultural systems reinforced the need for soil health improving agricultural practices. This study combines the two aspects and examines the effects of sustainable soil management practices on total energy consumption, specifically focusing on fertilizer and pesticide energies, as well as economic indicators such as contribution margins. Using Germany as a case study, we assess three general soil improving management practices: diversified crop rotations, organic fertilizers (green or liquid manure) instead of mineral fertilizers, and no-till/reduced till systems instead of ploughing. Drawing on data from the Kuratorium für Technik und Bauwesen in der Landwirtschaft e.V. (KTBL) (Board of Trustees for Technology and Construction in Agriculture) database for German agricultural planning, we consider variations in yield potentials, soil types, and farming systems. Our results reveal that using mineral fertilizers and shifting to more diverse crop rotations can reduce energy consumption by approximately 21,000 MJ/ha on average (7 % of total energy) over a 6-year rotation. Likewise, adopting no-till systems instead of ploughing decreases energy use by 12,000 MJ/ha (5 % of total energy). Economically, organic farming offers a €4000/ha higher contribution margin compared to conventional methods in fertilization and tillage. These sustainable practices improve soil health, conserve energy, and enhance economic viability. With fluctuating energy prices, organic farming could become more economically attractive and accelerate its adoption across agricultural landscapes.

Study on the relationship between high temperature oxidation and temperature rise rate of engine oil

Purpose The purpose of this paper is to study the relationship between high temperature oxidation and temperature rise rate of engine oil attempted to explore a new indicator to evaluate oil degradation. Design/methodology/approach Accelerated oxidation test combined with molecular simulation and road test is carried out in this paper. The temperature rise characteristics of mineral oil and synthetic oil under different oxidation temperatures (140°C, 155°C and 170°C) and time (50 h, 100 h, 150 h and 200 h) were determined by accelerated oxidation. The mechanism of temperature change characteristics of used oils was analyzed with molecular simulation. Two experimental vehicles carried six road tests with synthetic and mineral oil. Findings The results of this study show that the temperature rise rate of oxidized mineral and synthetic oil is higher than the new oil. The temperature rise rate is proportional to the oxidation time and oxidation temperature. The synthetic engine oil temperature rise rate is lower than that of the mineral engine oil. The same result was obtained in road tests. Molecular simulation verifies that small molecules were generated after oil oxidation which results in intermolecular friction and increased heat generation. Originality/value This paper indicates that temperature rise rate has potential to be taken as an indicator to evaluate oil oxidation which provides a new way for engine oil analysis. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-05-2024-0177/

Comparative Study of Suspended and Immobilized Bacteria Isolated from Garage Soil on Vegetable Oil Degradation

As an essential part of the ecosystem, soil helps to support life by promoting interactions between bedrock, water, air, and biota. But the growing number of oil spills has raised serious environmental issues, presenting problems similar to petroleum hydrocarbon pollution. Vegetable oils are generally thought to be safe, but because of their toxicity and persistence, they may have negative environmental impacts. Bioremediation techniques have gained popularity as a sustainable method of cleaning up hydrocarbon-contaminated locations in response to this environmental problem. This study uses immobilized microbial technology to increase the bioremediation effectiveness by examining the ability of bacteria isolated from a garage oil spill region to degrade vegetable oil. The study compares the degradation rates with naturally occurring bacteria to assess the effectiveness of the detected bacterium’s breakdown over time in both suspended and immobilized situations. The results add to our knowledge of microbial-mediated bioremediation in contaminated environments and highlight the promise of immobilized microbial technology as a workable method for reducing vegetable oil spills. After 45 days, immobilized bacteria showed a drastic reduction in hydrocarbon content compared to suspended bacteria, indicating increased efficacy. Moreover, the degradation rate of immobilized bacteria was significantly higher than that of suspended bacteria, as observed from the difference in hydrocarbon concentration between day 1 and day 45. Statistical analysis confirmed these findings, highlighting the effectiveness of immobilized bacteria in hydrocarbon degradation.

Development of poly(butylene oxalate-co-furanoate) copolymers with enhanced sustainability and hydrolytic degradability

Polyoxalate, a novel intrinsically hydrolysable polyester, garners significant interest for its high cost-effectiveness and versatility. However, concerns persist regarding its durability in practical applications. This study integrates bio-based poly(butylene furanoate) (PBF), which possesses remarkable barrier performance, into the poly(butylene oxalate) (PBOx) framework to synthesize poly(butylene oxalate‑co‑furanoate) (PBOF) with tunable degradation rates. The influence of incorporating BF units on thermal, crystalline, mechanical, and barrier properties was systematically analyzed. Results demonstrated the addition of BF units dramatically improved the balance between degradation and physical properties. Laboratory degradation experiments indicated that PBOF possessed significant degradation effects. Among them, PBOF-41 (with 41 % molar furanoate) decreased in weight by 20 % in freshwater, 70 % in an enzyme solution, and 8 % in artificial seawater within 30 days. After 28 days of degradation in soil, the residual weight was reduced to 80 % of its initial weight. Theoretical calculations and experiments have clarified the enhancement of the Gibbs free energy and energy barrier of the hydrolysis reaction by the BF unit. In summary, PBOF copolyesters have excellent gas barrier performance, adjustable thermal properties, well-balanced mechanical properties, and degradability, making them highly promising for sustainable plastic products.

Anaerobic Oxidation of Oil by Microbial Communities of Bottom Sediments of a Natural Oil Seepage Site (Bolshaya Zelenovskaya, Middle Baikal)

The microbial communities of bottom sediments of the Bolshaya Zelenovskaya oil seepage site (Lake Baikal) were investigated to assess their diversity and potential functional activity in the anaerobic degradation of oil. Microorganisms of the subsurface and deep sediment layers were grown in enrichment cultures supplemented with oil and various electron acceptors for 1 year at 10°C, and it was found that the concentrations of n-alkanes and polyaromatic hydrocarbons decreased by 1.2–2 and 2.2–2.8 times, respectively. Hydrocarbon conversion was accompanied by generation of hydrocarbon gases (methane and ethane). The microbial community of subsurface sediments had a higher bacterial diversity than the community of deep horizons and was composed of microorganisms specialized in degradation of a broad range of substrates, including oil hydrocarbons. The community of the deep sediment layer was dominated by Atribacterota, Caldisericota, and Bathyarchaeia (Thermoproteota), as well as members of the “rare biosphere”: Elusimicrobiota and Candidatus Hadarchaeota. Apparently, oil degradation in the bottom sediments of Lake Baikal is primarily mediated by members of the phyla Bacillota, Pseudomonadota, Chloroflexota, Actinomycetota, Desulfobacterota, Atribacterota, Halobacteriota, and Bathyarchaeia (Thermoproteota).

Transcriptional reprogramming of tomato (Solanum lycopersicum L.) roots treated with humic acids and filter sterilized compost tea

BackgroundTo counteract soil degradation, it is important to convert conventional agricultural practices to environmentally sustainable management practices. To this end, the application of biostimulants could be considered a good strategy. Compost, produced by the composting of biodegradable organic compounds, is a source of natural biostimulants, such as humic acids, which are naturally occurring organic compounds that arise from the decomposition and transformation of organic residues, and compost tea, a compost-derived liquid formulated produced by compost water-phase extraction. This study aimed to determine the molecular responses of the roots of tomato plants (cv. Crovarese) grown under hydroponic conditions and subjected to biostimulation with humic substances (HSs) and filtered sterile compost tea (SCT).ResultsThe 13C CPMAS NMR of humic acids (HA) and SCT revealed strong O-alkyl-C signals, indicating a high content of polysaccharides.Thermochemolysis identified over 100 molecules, predominantly from lignin, fatty acids, and biopolymers. RNA-Seq analysis of tomato roots treated with HA or SCT revealed differentially expressed genes (DEGs) with distinct patterns of transcriptional reprogramming.Notably, HA treatment affected carbohydrate metabolism and secondary metabolism, particularly phenylpropanoids and flavonoids, while SCT had a broader impact on hormone and redox metabolism. Both biostimulants induced significant gene expression changes within 24 h, including a reduction in cell wall degradation activity and an increase in the expression of hemicellulose synthesis genes, suggesting that the treatments prompted proactive cell wall development.ConclusionsThe results demonstrate that HS and SCT can mitigate stress by activating specific molecular mechanisms and modifying root metabolic pathways, particularly those involved in cell wall synthesis. However, gene regulation in response to these treatments is complex and influenced by various factors. These findings highlight the biostimulatory effects of HS and SCT, suggesting their potential application in crop biofertilization and the development of innovative breeding strategies to maximize the benefits of humic substances for crops. Further research is needed to fully elucidate these mechanisms across various contexts and plant species.

Biodegradation of &lt;i&gt;n&lt;/i&gt;-Alkanes in Oil-Contaminated Bottom Sediments under Bioelectrochemical Stimulation

Degradation of oil hydrocarbons artificially introduced into bottom sediments in a bioelectrochemical system of a membrane-free (silt) type was studied. Passive bioelectrochemical stimulation by means of electrodes connected by an external circuit with a resistance of 1 kΩ, with an average electric current of ~85 µA was found to cause an increase in degradation during two months from 23.0 to 57.9%. Contamination of bottom sediments with oil (1.32 g/kg) slightly decreased the current in the external circuit of the bioelectrochemical system. The relationship was revealed between the degree of oil degradation and predominant utilization of the lighter n-alkanes in the C14H30–C30H62 series, compared with both the original oil and the residual hydrocarbons of the control. An increase in the representation of the alkB alkane monooxygenase genes relative to the 16S rRNA gene in the total DNA isolated from the sediments was induced by the introduction of hexadecane, both in the case of electrochemical stimulation and in the control. The results may be of interest for the development of new methods of bioelectrochemical removal of organic pollutants from anaerobic environments.

Physical characterization of agar-based biodegradable films derived from nonhazardous laboratory waste

Globally, approximately 2.12 billion tons of waste are annually disposed of, with laboratories significantly contributing across diverse waste streams. Effective waste management strategies are crucial to mitigate environmental impact and promote sustainability within scientific communities. This study addresses the challenges by introducing a novel method that transforms laboratory media waste into a valuable biopolymer named “Agastic.” The process involves repurposing agar extracted from bulk laboratory waste, blending it with bio-based plasticizers to produce Agastic sheets exhibiting mechanical properties comparable to traditional bioplastics. Using response surface methodology (RSM) and central composite design (CCD), optimal concentrations of agar (1.5–2.5% w/v), glycerol (0.25–1% v/v), and ethanolamine (0.5–1.5% v/v) were determined. Predictions from Design Expert software indicated impressive tensile strength up to 14.31 MPa for AGA-1 and elongation at break up to 52% for AGA-2. Fourier Transform Infrared Spectroscopy (FTIR) analysis confirmed agarose structural features in AGA-1 and AGA-2. Thermogravimetric analysis (TGA) showed polysaccharide-related breakdown between 38°C and 280°C in AGA-1, peaking at 299.36°C; AGA-2 exhibited diverse thermal decomposition up to 765°C, suggesting their biodegradable potential in packaging applications. Scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS) analysis confirmed nontoxic nature of Agastic and preserved morphological integrity in both samples. Soil degradation studies revealed AGA-1 and AGA-2 losing 71.31% and 70.88% of weight, respectively, over 15 days. This innovation provides a sustainable pathway to repurpose laboratory waste into eco-friendly bioplastics, particularly suitable for moisture-sensitive packaging such as nursery applications. These findings underscore Agastic films’ promise as environmentally friendly alternatives to traditional plastics, supporting circular bioeconomy principles and significantly reducing ecological impacts associated with plastic waste.

Isotropic compression behavior of salinized unsaturated agricultural soil: An experimental and constitutive investigation

Salinity-induced soil degradation is a significant challenge in coastal reclamation areas, impacting agricultural productivity and infrastructure development. Variations in soil compression and deformation caused by changes in salinity warrant further investigation, particularly for agricultural applications. This study explores the relationship between soil pore water salinity and compressibility by conducting isotropic compression tests on salinized unsaturated agricultural soils treated with distilled water, 0.5 mol/L and 1 mol/L sodium chloride (NaCl) and calcium chloride (CaCl2) solutions. The results demonstrate that the type and concentration of salts significantly affect the compression behavior of these soils. The constitutive parameters were calibrated based on the experimental data. To account for osmotic suction, Barcelona Basic Model (BBM) was adjusted. The findings indicate that as pore water salinity increases, soil compressibility decreases, reflected by a compression index (Cc), and higher pre-consolidation stress (py). This modification aimed to quantify the impact of pore water salinity on soil compression. To validate the constitutive model, a numerical analysis of an isotropic compression test was carried out. This study contributes to our understanding of the isotropic compression behavior of coastal saline soil, proposes a constitutive framework for predicting soil responses under different salt conditions, and provides theoretical support for engineering construction in coastal reclamation areas.