Impact of residual antibiotics on microbial decomposition of livestock manures in Eutric Regosol: Implications for sustainable nutrient recycling and soil carbon sequestration.

The land application of livestock manure has been widely acknowledged as a beneficial approach for nutrient recycling and environmental protection. However, the impact of residual antibiotics, a common contaminant of manure, on the degradation of organic compounds and nutrient release in Eutric Regosol is not well understood. Here, we studied, how oxytetracycline (OTC) and ciprofloxacin (CIP) affect the decomposition, microbial community structure, extracellular enzyme activities and nutrient release from cattle and pig manure using litterbag incubation experiments. Results showed that OTC and CIP greatly inhibited livestock manure decomposition, causing a decreased rate of carbon (28%-87%), nitrogen (15%-44%) and phosphorus (26%-43%) release. The relative abundance of gram-negative (G-) bacteria was reduced by 4.0%-13% while fungi increased by 7.0%-71% during a 28-day incubation period. Co-occurrence network analysis showed that antibiotic exposure disrupted microbial interactions, particularly among G- bacteria, G+ bacteria, and actinomycetes. These changes in microbial community structure and function resulted in decreased activity of urease, ß-1,4-N-acetyl-glucosaminidase, alkaline protease, chitinase, and catalase, causing reduced decomposition and nutrient release in cattle and pig manures. These findings advance our understanding of decomposition and nutrient recycling from manure-contaminated antibiotics, which will help facilitate sustainable agricultural production and soil carbon sequestration.

Design and properties of ternary alkali-activated binder based on blast furnace slag, recycled powder and waste glass powder.

Ternary alkali-activated binder was prepared by blast furnace slag (GGBS), recycled powder (RP) and waste glass powder (WGP) using simplex centroid design method. By measuring the fluidity, setting time, drying shrinkage and mechanical property of specimen, the complementary effect of GGBS, RP and WGP was discussed. The reaction mechanism and microstructure were explored by X-ray diffraction and scanning electron microscopy. The results reveal that the addition of RP could significantly reduce the fluidity and setting time of paste, while WGP can obviously improve the rheological property and play a retarding role. The workability of paste can be effectively regulated by mixing RP and WGP together. Whether added alone or in combination, RP and WGP can effectively improve the shrinkage performance. In the ternary system, GGBS can be rapidly activated and form a skeleton structure. The fine RP particles can play a good role in filling the structure, and the pozzolanic reaction of WGP gradually occurs, which makes the microstructure more compact. The incorporation of GGBS, RP and WGP can promote the growth of hydration products, improve the density of microstructure, and form a certain complementary effect.

Towards cleaner environment: recycling microalgal co-product to reduce emissions and impacts while eliminating fishmeal in rainbow trout feed for sustainable aquaculture.

The rapid increase in aquaculture over the last several decades has led to concerns about the environmental impact of fish feeds relying on marine resources for fishmeal (FM). We aim to assess Nannochloropsis sp. QH25 co-product as a viable and sustainable replacement for FM in juvenile rainbow trout, Oncorhynchus mykiss, feeds. We formulated four experimental diets: a reference (FM based), 33N, 66N, and 100N diet (33%, 66%, and 100% co-product replacement). Rainbow trout were randomly assigned to one of 16 tanks and randomly assigned an experimental diet to consume throughout the experiment (64 days total), with four replicate tanks per diet. We compared the phosphorus (P) and nitrogen (N) digestibility, emissions, and growth between diets and, compared six environmental impacts (biotic resource use (BRU), global warming potential (GWP), water use, land use, marine eutrophication potential (MEP), and freshwater eutrophication potential (FEP)) of each diet. Our results indicate that replacing FM with co-product did not significantly alter growth. P digestibility of the experimental and reference diets was comparable. BRU conversion ratio was significantly lower in the experimental diets. However, there were significantly higher water and land use conversion ratios but insignificantly higher results in GWP, MEP, and FEP between the reference and 100N diet.

A Recyclable Polypropylene Multilayer Film Maintaining the Quality and the Aroma of Coffee Pods during Their Shelf Life.

Films for coffee-pod packaging usually contain aluminium as an impermeable foil that is not recyclable and has to be discharged as waste. In this study, a recyclable polypropylene multilayer film is proposed as an alternative. The performance on the chemical composition of coffee was evaluated and compared to that of film containing aluminium (standard). The oxygen in the headspace, moisture, lipidic oxidation, and volatile organic compounds were studied in coffee pods during storage for 12 months at 25 and 40 °C. In addition, the acidity and acceptability of extracted coffee were evaluated. In the polypropylene-packaged pods, the percentage of oxygen during storage at 25 °C was lower than that in the standard. Moisture was not affected by the type of packaging materials. No differences were found between the peroxide values, except in pods stored for 3, 10, and 11 months at 25 °C, where they were even lower than the standard. Furans and pyrazines were the main volatile organic compounds detected. No differences were found in the pH and titratable acidity of the coffee brew either. All samples were well accepted by consumers without any perceived difference related to the packaging film. The polypropylene multilayer film is a sustainable recyclable material with high performance, in particular, against oxygen permeation.

Circular economy life cycle cost for kerbside waste material looping process.

Rapid expansion in urban areas has engendered a superfluity of municipal solid waste (MSW) stemming from contemporary civilization, encompassing commercial sectors and human undertakings. Kerbside waste, a type of MSW, has the potential for recycling and reuse at the end of its first life cycle, but is often limited to a linear cycle. This study aimed to assess the life cycle costs of different separation and recycling methods for handling kerbside waste. A new life cycle cost model, drawing from the circular economy's value retention process (VRP) model, has been created and applied to assess the continuous recycling of kerbside glass. The study investigates two key separation techniques, kerbside recycling mixed bin recycling (KRMB) kerbside glass recycling separate bin (KGRSB) and analyses their impact on the life cycle cost of the recycling process. Additionally, the research explores two approaches of recycling and downcycling: closed-loop recycling, which pertains to the recycling of glass containers, and open-looped recycling, which involves the use of recycled glass in asphalt. The results showed when use annually collected waste as the functional unit, the KRMB model incurred lower costs compared to the KGRSB model due to its lower production output. However, when evaluated over a 1-ton production of glass container and asphalt, the KGRSB method demonstrated superior cost performance with a 40-50% reduction compared to the KRMB method. The open-loop recycling method (asphalt) incurred a higher cost compared to the closed-loop recycling method due to its larger production volume over a 21-year period.

Strategies to enhance the circularity of non-bottle PET packaging waste based on a detailed material characterisation.

The compositions of Dutch lightweight packaging waste (LWP) and sorted products named "PET (Polyethylene terephthalate) trays" have been determined on object level. Additionally, the PET trays from both waste types were sorted in 16 categories representing their packaging use and material build-up. The material composition of at least 10 representative trays from each category was determined with chemical and thermal analysis, based on which the average material composition per category was established. Based on this data the average material composition of sorted PET tray products was approximated. The recyclability of the various categories of PET trays was assessed based on their material build-up. The most ubiquitous PET trays in Dutch LWP and sorted products were only found to be suitable to produce opaque recycled PET with mechanical recycling processes. Whereas only some more uncommon PET trays can be used to produce transparent recycled PET with mechanical recycling processes. Depolymerisation is deemed to be a more appropriate recycling process that will allow the production of transparent food-grade recycled PET.

Nutritional and sensory parameters of amazake from the recycling of stale bread.

Stale bread is a waste product with a potential to be recycled. One way to manage this waste material is to process it by fermentation for the purpose of food production. This paper proposes the use of stale wheat and rye bread as ingredients in amazake, a liquid dessert traditionally obtained from rice by fermentation with the koji mould Aspergillus oryzae, followed by liquefaction by the action of fungal enzymes. The stale bread was introduced instead of rice at both the koji stage (wheat bread) and the liquefaction stage (wheat and rye bread). The resulting products had an extended volatile compound profile, from 5 to 15 compounds identified, and modified sensory parameters, compared to the traditional version. Amazake containing bread had an increased protein content, from 1.10 to 6.4 g/100 g, and were more abundant in dietary fibre (up to a maximum of 1.8 g/100 g), additionally enriched with a soluble fraction. The proposed procedure of obtaining of new formula amazake can be directly applied in households to reduce the amount of discarded bread. Due to its simplicity, it also has the potential for further modification in terms of production scale and product parameters.

The influence of chlorination additives on metal separation during the pyrometallurgical recovery of spent lithium-ion batteries.

The difficulty of separating Li during pyrometallurgical smelting of spent lithium-ion batteries (LIBs) has limited the development of pyrometallurgical processes. Chlorination enables the conversion of Li from spent LIBs to the gas phase during the smelting process. In this paper, the effects of four solid chlorinating agents (KCl, NaCl, CaCl2 and MgCl2) on Li volatilization and metal (Co, Cu, Ni and Fe) recovery were investigated. The four solid chlorinating agents were systematically compared in terms of the direct chlorination capacities, indirect chlorination capacities, alloy physical losses and chemical losses in the slag. CaCl2 was better suited for use as a solid chlorinating agent to promote Li volatilization due to its excellent results in these indexes. The temperature required for the release of HCl from MgCl2, facilitated by CO2 and SiO2, was lower than 500 °C. The prematurely released HCl failed to participate in the chlorination reaction. This resulted in approximately 12 % less Li volatilization when MgCl2 was used as a chlorinating agent compared to when CaCl2 was used. In addition, the use of KCl as a chlorinating agent decreased the chemical dissolution loss of alloys in the slag. The performance of NaCl was mediocre. Finally, based on evaluations of the four indexes, recommendations for the selection and optimization of solid chlorinating agents were provided.

Converting fruit peels into biodegradable, recyclable and antimicrobial eco-friendly bioplastics for perishable fruit preservation.

The development of biodegradable antimicrobial bioplastics for food packaging holds great promise for solving the pollution and safety problems caused by petrochemical plastics and spoiled food. Herein, a natural active-bioplastic synthesized from citrus peel biomass is presented for perishable fruit preservation. These plastics are characterized by the nanoscale entanglement and recombinant hydrogen bonding between the endogenous pectin, polyphenols and cellulose micro/nanofibrils. They have attractive flexibility, tensile strength, gas barrier properties and antimicrobial activities, and can effectively extend the shelf life of perishable fruits such as banana and mango when used as food packaging. Cytotoxicity, degradability tests and life-cycle assessment show that these plastics had excellent nontoxicity and can be safely degraded or easily recycled. This work demonstrates a sustainable strategy for converting peel waste into eco-friendly bioplastics, providing a unique and novel insight into radically reducing the pollution and life-health threats posed by petrochemical plastics and spoiled food.

Stepwise extraction of lithium and potassium and recovery of fluoride from aluminum electrolyte wastes through calcification roasting-two-stage leaching.

Aluminum electrolyte is a necessity for aluminum reduction cells; however, its stock is rising every year due to several factors, resulting in the accumulation of solid waste. Currently, it has become a favorable material for the resources of lithium, potassium, and fluoride. In this study, the calcification roasting-two-stage leaching process was introduced to extract lithium and potassium separately from aluminum electrolyte wastes, and the fluoride in the form of CaF2 was recycled. The separation behaviors of lithium and potassium under different conditions were investigated systematically. XRD and SEM-EDS were used to elucidate the phase evolution of the whole process. During calcification roasting-water leaching, the extraction efficiency of potassium was 98.7% under the most suitable roasting parameters, at which the lithium extraction efficiency was 6.6%. The mechanism analysis indicates that CaO combines with fluoride to form CaF2, while Li-containing and K-containing fluorides were transformed into water-insoluble LiAlO2 phase and water-soluble KAlO2 phase, respectively, thereby achieving the separation of two elements by water leaching. In the second acid-leaching stage, the extraction efficiency of lithium was 98.8% from water-leached residue under the most suitable leaching conditions, and CaF2 was obtained with a purity of 98.1%. The present process can provide an environmentally friendly and promising method to recycle aluminum electrolyte wastes and achieve resource utilization.

Engineered polyethylene terephthalate hydrolases: perspectives and limits.

Polyethylene terephthalate (PET) is a major component of plastic waste. Enzymatic PET hydrolysis is the most ecofriendly recycling technology. The biorecycling of PET waste requires the complete depolymerization of PET to terephthalate and ethylene glycol. The history of enzymatic PET depolymerization has revealed two critical issues for the industrial depolymerization of PET: industrially available PET hydrolases and pretreatment of PET waste to make it susceptible to full enzymatic hydrolysis. As none of the wild-type enzymes can satisfy the requirements for industrialization, various mutational improvements have been performed, through classical technology to state-of-the-art computational/machine-learning technology. Recent engineering studies on PET hydrolases have brought a new insight that flexibility of the substrate-binding groove may improve the efficiency of PET hydrolysis while maintaining sufficient thermostability, although the previous studies focused only on enzymatic thermostability above the glass transition temperature of PET. Industrial biorecycling of PET waste is scheduled to be implemented, using micronized amorphous PET. Next stage must be the development of PET hydrolases that can efficiently degrade crystalline parts of PET and expansion of target PET materials, not only bottles but also textiles, packages, and microplastics. This review discusses the current status of PET hydrolases, their potential applications, and their profespectal goals. KEY POINTS: • PET hydrolases must be thermophilic, but their operation must be below 70 °C • Classical and state-of-the-art engineering approaches are useful for PET hydrolases • Enzyme activity on crystalline PET is most expected for future PET biorecycling.

Associations of insulin sensitivity and immune inflammatory responses with child blood lead (Pb) and PM2.5 exposure at an e-waste recycling area during the COVID-19 lockdown.

Fine particular matter (PM2.5) and lead (Pb) exposure can induce insulin resistance, elevating the likelihood of diabetes onset. Nonetheless, the underlying mechanism remains ambiguous. Consequently, we assessed the association of PM2.5 and Pb exposure with insulin resistance and inflammation biomarkers in children. A total of 235 children aged 3-7 years in a kindergarten in e-waste recycling areas were enrolled before and during the Corona Virus Disease 2019 (COVID-19) lockdown. Daily PM2.5 data was collected and used to calculate the individual PM2.5 daily exposure dose (DED-PM2.5). Concentrations of whole blood Pb, fasting blood glucose, serum insulin, and high mobility group box 1 (HMGB1) in serum were measured. Compared with that before COVID-19, the COVID-19 lockdown group had lower DED-PM2.5 and blood Pb, higher serum HMGB1, and lower blood glucose and homeostasis model assessment of insulin resistance (HOMA-IR) index. Decreased DED-PM2.5 and blood Pb levels were linked to decreased levels of fasting blood glucose and increased serum HMGB1 in all children. Increased serum HMGB1 levels were linked to reduced levels of blood glucose and HOMA-IR. Due to the implementation of COVID-19 prevention and control measures, e-waste dismantling activities and exposure levels of PM2.5 and Pb declined, which probably reduced the association of PM2.5 and Pb on insulin sensitivity and diabetes risk, but a high level of risk of chronic low-grade inflammation remained. Our findings add new evidence for the associations among PM2.5 and Pb exposure, systemic inflammation and insulin resistance, which could be a possible explanation for diabetes related to environmental exposure.

A novel closed-loop biotechnology for recovery of cobalt from a lithium-ion battery active cathode material.

In recent years, the demand for lithium-ion batteries (LIBs) has been increasing rapidly. Conventional recycling strategies (based on pyro- and hydrometallurgy) are damaging for the environment and more sustainable methods need to be developed. Bioleaching is a promising environmentally friendly approach that uses microorganisms to solubilize metals. However, a bioleaching-based technology has not yet been applied to recover valuable metals from waste LIBs on an industrial scale. A series of experiments was performed to improve metal recovery rates from an active cathode material (LiCoO2; LCO). (i) Direct bioleaching of ≤0.5 % LCO with two prokaryotic acidophilic consortia achieved >80 % Co and 90 % Li extraction. Significantly lower metal recovery rates were obtained at 30 °C than at 45 °C. (ii) In contrast, during direct bioleaching of 3 % LCO with consortia adapted to elevated LCO levels, the 30 °C consortium performed significantly better than the 45 °C consortium, solubilizing 73 and 93 % of the Co and Li, respectively, during one-step bioleaching, and 83 and 99 % of the Co and Li, respectively, during a two-step process. (iii) The adapted 30°C consortium was used for indirect leaching in a low-waste closed-loop system (with 10 % LCO). The process involved generation of sulfuric acid in an acid-generating bioreactor (AGB), 2-3 week leaching of LCO with the biogenic acid (pH 0.9), selective precipitation of Co as hydroxide, and recirculation of the metal-free liquor back into the AGB. In total, 58.2 % Co and 100 % Li were solubilized in seven phases, and >99.9 % of the dissolved Co was recovered after each phase as a high-purity Co hydroxide. Additionally, Co nanoparticles were generated from the obtained Co-rich leachates, using Desulfovibrio alaskensis, and Co electrowinning was optimized as an alternative recovery technique, yielding high recovery rates (91.1 and 73.6% on carbon felt and roughened steel, respectively) from bioleachates that contained significantly lower Co concentrations than industrial hydrometallurgical liquors. The closed-loop system was highly dominated by the mixotrophic archaeon Ferroplasma and sulfur-oxidizing bacteria Acidithiobacillus caldus and Acidithiobacillus thiooxidans. The developed system achieved high metal recovery rates and provided high-purity solid products suitable for a battery supply chain, while minimizing waste production and the inhibitory effects of elevated concentrations of dissolved metals on the leaching prokaryotes. The system is suitable for scale-up applications and has the potential to be adapted to different battery chemistries.

Materials Challenges in the Electric Vehicle Transition.

The ongoing transition toward electric vehicles (EVs) is changing materials used for vehicle production, of which the consequences for the environmental performance of EVs are not well understood and managed. We demonstrate that electrification coupled with lightweighting of automobiles will lead to significant changes in the industry's demand not only for battery materials but also for other materials used throughout the entire vehicle. Given the automotive industry's substantial consumption of raw materials, changes in its material demands are expected to trigger volatilities in material prices, consequently impacting the material composition and attractiveness of EVs. In addition, the materials recovered during end-of-life recycling of EVs as the vehicle fleet turns over will impact recycled material supplies both positively and negatively, impacting material availabilities and the economic incentive to engage in recycling. These supply chain impacts will influence material usage and the associated environmental performance of not only the automotive sector but also other metal-heavy industries such as construction. In light of these challenges, we propose the need for new research to understand the dynamic materials impacts of the EV transition that encompasses its implications on EV adoption and fleet life cycle environmental performance. Effectively coordinating the coevolution of material supply chains is crucial for making the sustainable transition to EVs a reality.

Understanding medication recycling practices in Canadian hospitals.

BACKGROUND: Medication recycling within hospitals has proven financial and possible environmental benefits according to local evaluations done in British Columbia. Despite this, the extent of medication recycling in Canadian hospitals remains unclear in the literature. OBJECTIVE(S): To determine if Canadian hospitals recycle medications, provide an estimate of how much medication is recycled by dosage form, and identify medication recycling barriers through the distribution of a cross-sectional survey. METHODS: A nine-question survey was distributed to 171 hospital pharmacy departments across Canada that consented to complete the survey. The survey identified whether sites recycled unused medications, an estimate of how much is recycled based on dosage form, and barriers to recycling. KEY FINDINGS: Of 62 respondents, the majority indicated they do have medication recycling procedures; however, the frequency of recycling is suboptimal (30-50% of medications are not recycled), and not all medication types are always recycled. Individually packaged oral tablets were most often recycled, and oral liquid medications were least often recycled. Many multi-dose medications were not tamper-proofed. Most respondents selected "sanitization/infection control" and "resource constraint" as reasons for not recycling all medications. CONCLUSIONS: Among respondents, the proportion and type of unused medicines that are recycled varied. For sites that did not respond, this might suggest that medication recycling is not a priority. This could represent a missed opportunity to standardize practices and increase medication recycling in hospitals, both of which could represent a meaningful step towards responsible use of medications and reduction of negative impacts on human health and the environment.

Gate-to-grave assessment of plastic from recycling to manufacturing of TENG: a comparison between India and Singapore.

This study assesses the viability of recycled plastic-based triboelectric nanogenerators (TENGs) for sustainable energy harvesting in India and Singapore, concurrently examining plastic waste management. Using material flow analysis and life cycle assessment, the findings revealed that in Singapore, waste-to-energy incineration has a lower environmental impact than landfilling and mechanical recycling, attributed to natural gas usage. In India, recycling offsets impacts from incineration and landfilling, contributing to a lower net environmental impact. Economic performance of a TENG module from PET recyclates showed a 20% carbon footprint reduction when scaling up from lab to industrial "freeze-drying" processes. Key challenges in TENG manufacturing processes are also assessed for future development. This research highlights the potential of recycled plastic-based TENGs in sustainable energy and waste management.

Urgent needs for second life using and recycling design of wasted electric vehicles (EVs) lithium-ion battery: a scientometric analysis.

Currently, lithium-ion batteries are increasingly widely used and generate waste due to the rapid development of the EV industry. Meanwhile, how to reuse "second life" and recycle "extracting of valuable metals" of these wasted EVBs has been a hot research topic. The 4810 relevant articles from SCI and SSCI Scopus databases were obtained. Scientometric analysis about second life using and recycling methodologies of wasted EVBs was conducted by VOSviewer, Pajek, and Netdraw. According to analytical results, the research of second life using and recycling mythologies has been growing and the expected achievement will continue to increase. China, Germany, the USA, Italy, and the UK are the most active countries in this field. Tsinghua University in China, "Fraunhofer ISI, Karlsruhe" in Germany, and "Polytechnic di Torino" in Italy are the most productive single and collaborative institutions. The journals SAE technical papers and World Electric Vehicle Journal have the highest publication and citations than other journals. Chinese author "Li Y" has the highest number of 36 publications, and his papers were cited 589 times by other authors. By analyzing the co-occurrence and keywords, energy analysis, second life (stationary using, small industry), and treatment methods, (hydrometallurgy and pyrometallurgical, electrochemical, bio-metallurgical) were the hot research topics. The S-curve from the article indicates hydrometallurgical and bio-metallurgical methods are attached with great potential in the near future. Further, different treatment methodologies are observed especially advanced techniques in hydrometallurgical, and spent medium bioleaching techniques in bio-metallurgical are good, economically cheap, has low CO2 emission, environmentally friendly, and has high recovery rate. Finally, this research provides information on second life use and top recycling methodology opportunities for future research direction for researchers and decision-makers who are interested in this research.

Pyrolytic urban mining of waste printed circuit boards: an enviro-economic analysis.

E-waste, a global environmental concern resulting from supply chain inefficiency, also offers the opportunity to recover valuable materials, including general and rare earth metals. Waste printed circuit boards (WPCBs) are integral components of e-waste that contains substantial amounts of precious metals, making them a valuable waste category. Pyrolysis has emerged as a promising method for material recovery from WPCBs. Hence, pyrolytic urban mining of WPCBs offers an excellent avenue for resource recovery, redirecting valuable materials back into the supply chain. Under the current study, experimental investigation has been conducted to explore the recovery of materials from WPCBs through pyrolysis followed by process simulation, economic analysis, and life cycle assessment (LCA). An Aspen Plus simulation was conducted to model the pyrolysis of WPCBs and subsequent product recovery using a non-equilibrium kinetic model, which represents a unique approach in this study. Another distinct aspect is the comprehensive assessment of environmental and economic sustainability. The economic analysis has been carried out using Aspen economic analyzer whereas the LCA of WPCB pyrolysis has been conducted using the SimaPro software. The experimental investigation reveals yield of solid residues are about 75-84 wt.%, liquid yields of 6-13 wt.%, and gas yields of 4-21 wt.%, which is in well agreement with the Aspen Plus simulation results. The economic analysis for an e-waste pyrolysis plant with an annual feed rate of 2000 t reveals that the total capital cost of a pyrolysis plant is nearly $51.3 million, whereas the total equipment cost is nearly $2.7 million and the total operating cost is nearly $25.6 million. The desired rate of return is 20% per year and the payback period is 6 years with a profitability index of 1.25. From the LCA, the major impact categories are global warming, fossil resource scarcity, ozone formation in human health, ozone formation in terrestrial ecosystems, fine particulate matter formation, and water consumption. The findings of this study can serve as a guideline for e-waste recyclers, researchers, and decision-makers in establishing circular economy.

Harvest residue recycling rather than slash-burning results in the enhancement of soil fertility and bacterial community stability in Eucalyptus plantations.

Deforestation and slash combustion have substantial adverse impacts on the atmosphere, soil and microbe. Despite this awareness, numerous individuals persist in opting for high-intensity Eucalyptus planting through slash-burning in pursuit of immediate profits while disregarding the environmental significance and destroying the soil. Slash-unburnt agriculture can effectively safeguard the ecological environment, and compared with slash-burning, there remains a limited understanding of its regulatory mechanisms on soil fertility and microbial community. Also, large uncertainty persists regarding the utilization of harvest residues. Thoroughly investigating these questions from various perspectives encompassing physical soil characteristics, nutrient availability, bacterial community structures, and stability is crucial. To explore the ecological advantages of slash-unburnt techniques on microorganisms and their associated ecosystems, we used two slash-unburnt (Unburnt) planting techniques: Spread (naturally and evenly covering the forest floor after logging) and Stack (residues are piled along contour lines) as well as the traditional slash Burnt method (Burnt) in a Eucalyptus plantation. A comparative analysis was conducted between the two methods. We observed that over a span of 4 years, despite the initial lower application of fertilizer in the Unburnt treatments compared with the Burnt treatment during the first 2 years, the Unburnt treatment gradually caught up or even surpassed and attained similar nutrient levels as the Burnt treatment. Alphaproteobacteria was the main phyla that indicated the difference in soil bacterial communities between Burnt and Unburnt treatments. The microbial networks also highlighted the significance of the Unburnt method, as it contributed to the preservation of crucial network nodes and the stability of soil bacterial communities. Therefore, rational utilization of harvest residue may effectively avoid the vast damage caused by slash-burning to Eucalyptus trees and the soil environment but may also increase the potential for restoring soil fertility, improving fertilizer utilization efficiency, and maintaining microbial community stability over time.