Search Results (3,676)

Tobacco (Nicotiana tabacum L.) is an industrial crop cultivated worldwide with intensive management systems that include continuous cropping, conventional tillage and high use of agrochemicals. The increasing concerns about environmental and economic sustainability call for innovative practices to maintain yield while managing weeds and enhancing soil fertility. Our research investigated the effect of green manure or cover crops coupled with minimum tillage on Kentucky tobacco production and the level of control of weeds. Six integrated management systems were tested in a four-year trial in Tuscany, Italy: (TS1) conventional farming management as defined above; (TS2) reduction in fertilizers and compost application; (TS3) rotation of tobacco–leguminous green manure and reduction in fertilizers; (TS4) rotation of tobacco–leguminous green manure and compost application without fertilizers; (TS5) rotation of tobacco–mixture of cover crops, minimum tillage before tobacco transplant, reduction in fertilizers; (TS6) as in TS5 but with a compost amendment addition. The different farming practices represented an ecological filter for the weed communities. The combination of conventional tillage, compost application and green manure was sufficient to control weed development. On the other hand, cover crop termination via roller crimper and minimum tillage did not reduce weed pressure, thereby negatively affecting tobacco production. Further studies are needed to improve the effectiveness of mulching and minimal tillage on weed levels not detrimental to tobacco development. It would be advisable to alternate different weed management strategies to prevent community specialization, mitigate negative effects on crops and enhance biodiversity at the farm scale. Full article

Olive pomace is an abundant agro-industrial residue whose recalcitrant composition limits its efficient valorisation, highlighting the need for sustainable recovery strategies. This study investigated the use of Hermetia illucens larvae for the bioconversion of olive pomace and its integration with anaerobic digestion to evaluate the simultaneous recovery of biomass and energy. Larvae were initially reared on olive pomace, goat manure, and their mixture to assess growth performance, survival, and substrate suitability. Subsequently, olive pomace was subjected to thermal pre-treatment and anaerobic digestion with goat manure, and the resulting digestates were reused as substrates for larval rearing. Their phytotoxicity was also evaluated through germination tests on alfalfa. Larval performance was higher on non-digested substrates, confirming the suitability of raw mixtures for insect rearing. Thermal pre-treatment did not result in a significant increase in methane production. In contrast, digestates, particularly those obtained under more severe thermal treatments, resulted in reduced larval growth and survival under the tested conditions and showed variable phytotoxic effects. Overall, although anaerobic digestion enabled energy recovery, its integration with insect-based bioconversion resulted in reduced larval performance under the tested conditions. These findings highlight the importance of optimising substrate treatment to ensure effective integration of insect rearing within circular bioeconomy systems. Full article

The increasing volume of plant-based waste generated by the agri-food sector represents both an environmental challenge and an underexploited biotechnological resource. These wastes, rich in lignocellulosic compounds, constitute a natural habitat for specialized microorganisms. The aim of this article is to provide a critical review of the potential use of such wastes—specifically straw, pomace, and manure—in two complementary ways: (1) as a specific source for isolating new microbial strains with high biodegradation capacity and plant-growth-promoting potential, and (2) as a low-cost substrate for their propagation, e.g., in solid-state fermentation processes. This dual perspective represents a novel, integrative approach, as previous reviews typically address these aspects in isolation rather than considering their synergistic potential. The article discusses the relationship between the chemical composition of selected wastes (straw, pomace, manure) and the targeted selection of desirable microbiological traits. Particular emphasis is placed on advanced, integrated approaches for assessing microbial potential, combining phenotyping (zymography, activity assays), genomics (whole-genome sequencing—WGS, identification of CAZyme genes and biosynthetic gene clusters), and metabolomics (metabolite profiling, 3D MSI imaging). The limitations of individual methods are critically evaluated, and key research gaps are identified, including the need for in situ validation of omics-based findings and the development of stable microbial consortia with predictable performance under variable environmental conditions. These gaps are discussed in the broader context of circular bioeconomy and sustainable agriculture, highlighting the strategic relevance of integrating waste valorization with microbiome-based biotechnological innovations. Full article

Extended-spectrum β-lactamase (ESBL)-producing bacteria are a growing public health concern within the One Health framework. This study aimed to characterize ESBL-producing Enterobacterales in industrial and artisanal organic fertilizers marketed in southwestern Colombia. Five commercial fertilizer brands were analyzed using a selective culture on ceftriaxone supplemented media (4 µg/mL), antimicrobial susceptibility testing by broth microdilution to determine minimum inhibitory concentrations (MICs), phenotypic synergy testing for ESBL confirmation, and polymerase chain reaction (PCR) to detect bla_TEM, bla_SHV, and bla_CTX-M genes. Overall, 18.6% of the samples showed growth of ceftriaxone-resistant Enterobacterales, predominantly Escherichia coli and Klebsiella pneumoniae. ESBL producers accounted for 84% of the isolates, all of which carried at least one bla gene, predominantly bla_CTX-M. Statistically significant differences in bacterial growth frequency were observed among fertilizer types, with higher positivity rates observed in manure-based artisanal formulations (p < 0.05). Whole-genome sequencing of selected isolates identified Klebsiella pneumoniae ST37 and Escherichia coli ST224, both harboring bla_CTX-M-55 and additional resistance and virulence determinants. These findings demonstrate that organic fertilizers, particularly manure-derived products, may act as reservoirs and potential dissemination routes for clinically relevant antimicrobial-resistant bacteria. This is the first study in Colombia documenting the presence of ESBL-producing bacteria in organic fertilizers. These results underscore the need to incorporate surveillance of these products into national policies under a One Health perspective. Full article

For optimal growth and development, black soldier fly larvae require a balanced diet. This study focused on how nutrients other than protein, specifically fat, starch, fibre, and ash, affect larval growth, body composition, and the quality of the leftover material called frass. To isolate the effects of these nutrients, five types of organic byproducts: fast food (FF) waste, solid pig manure (PS), mushroom stems (MS), slaughter waste (SW) and poultry meal (PM), were used to create six different diets, all with similar protein levels (about 22% DM). The results showed that diets rich in fat and starch, such as those based on FF waste, produced the heaviest larvae (155.9 mg), which also had high fat (30.31% DM) and protein contents (52.74% DM). In contrast, diets based on PM, which were low in fat and starch but high in fibre and ash, resulted in lower larval weight, which had lower fat content but variable protein content depending on other diet ingredients. Similar dietary protein levels yielded different larval protein contents, indicating that other nutrients may have influenced how protein was stored. However, other components of the diet, especially fat and ash, were consistently reflected in both the larvae and the frass. Overall, the study shows that nutrients other than protein play important roles in larval development and should be considered when designing black soldier fly diets. Full article

The deposition of volcanic ash in areas affected by erupting volcanoes can contaminate the soil with heavy metals, thereby jeopardizing food security and public health. This study focused on the use of compost for the bioremediation of this type of contaminated soil and on evaluating the effectiveness of this remediation technique in a horticultural crop. To this end, composts made from organic waste generated in the areas with volcanic-ash-affected soil, such as crop residues, cow manure, and cheese whey, were used. The design and optimization of the composting process for these wastes were described using three piles with the same proportion of crop residues and cow manure but different doses of whey (pile 1: without whey, pile 2: whey diluted with water (1:2 (v:v)); and pile 3: with undiluted whey) and by monitoring the evolution of physicochemical and biological parameters throughout the compositing process. The effectiveness of the composts obtained for soil remediation was evaluated by assessing the physiological response of a lettuce crop in pots. Five treatments were used: control soil without fertilization, inorganic fertilization, and the three composts obtained. The main agronomic properties of the soil and heavy metal availability were measured, along with the physiological and chemical parameters of the lettuce, including growth and macronutrient and heavy metal content. The results obtained in the composting experiment showed that the addition of cheese whey only affected the rate of organic matter degradation and the salt content of the final composts, without negatively affecting the stability and humification of their organic matter or their plant nutrient content. In the pot experiment, all composts improved soil fertility and reduced the availability of Ni, As, Cd, and Pb, but this did not consistently reduce uptake into lettuce, except in the case of Pb. Therefore, it is advisable to adjust the compost application rate and optimize crop selection to minimize the impact of heavy metals on the food chain, thereby ensuring safe production. Full article

In southern China, Chinese milk vetch is used as green manure to substitute for inorganic nitrogen (N) fertilizers and improve soil fertility, but how different incorporation methods affect its decomposition and underlying microbial mechanisms is unclear. This study used four fertilization regimes (CK: no N; CF: sole chemical N; CM: sole vetch; CMCF: vetch + 40% reduced N) to evaluate bacterial diversity, community composition and life history strategies during early vetch decomposition, and the nylon bag method to compare decomposition and C/N release dynamics. The results show that vetch dry matter decomposition reached 81.9–85.2% in 34 days, slowing to 11.8–14.4% after 192 days. CMCF significantly accelerated early decomposition and N release compared with CM. While CMCF reduced the bacterial Ace and Chao indices compared to CK with similar community structure, CF/CM exhibited distinct community structures. Compared to CM, CMCF increased r-strategy bacteria (e.g., Proteobacteria, Bacteroidota) and decreased K-strategy ones (e.g., Chloroflexi). Furthermore, decomposition rate positively correlated with r-strategy and negatively with K-strategy bacteria, with soil temperature as the primary driver. Compared to CMCF, CM reduced bacterial network complexity, decreasing nodes by 63.6% and average degree by 68.5%. In conclusion, combining vetch with chemical N enhances vetch residue decomposition while preserving microbial network structure and functional diversity. Full article

The decline of soil organic matter in Kazakhstan due to long-term monoculture and intensive fertilizer use has increased the need for sustainable soil management strategies. This study aimed to develop a new composting technique to produce more performant organic fertilizers from cattle manure to contribute to the broader strategy to increase soil organic matter and to improve fertility in northern Kazakhstan soils. Composting experiments were conducted using oxidized coal at 5%, 10%, and 20% dosages combined with two microbial consortia, and physicochemical and microbiological parameters were monitored throughout the process. The addition of microbial consortia and oxidized coal significantly enhanced composting dynamics by accelerating the transition to the thermophilic phase and increasing microbial activity. Treated systems exhibited higher temperatures (up to 48–49 °C), greater microbial abundance, and improved nitrogen transformation, characterized by increased NH₄⁺–N accumulation followed by NO₃⁻–N formation. Organic matter degradation was more efficient in amended treatments, while oxidized coal contributed to improved moisture retention and pH stabilization. However, excessive coal addition (20%) reduced microbial activity at later stages. Among the treatments, the combination of Consortium 3 with 10% oxidized coal showed the most balanced performance, with enhanced microbial activity, efficient nutrient transformation, and stable compost maturation. These findings demonstrate that the integration of microbial consortia with oxidized coal is an effective strategy for improving composting efficiency and producing high-quality organo-mineral fertilizers, with potential for improving compost quality and nutrient stabilization, and supporting sustainable and regenerative soil management in degraded agricultural systems. Full article

Animal manure represents a critical reservoir that facilitates the dissemination of antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs). However, the current understanding of ARG evolution during extensive composting remains insufficient. This study systematically investigated two common aerobic composting techniques: push-flow trough composting (FC) and membrane-covered composting (FM). Results indicated that both processes demonstrated substantial antibiotic removal capacities, achieving total removal rates of 88.89% (FC) and 79.20% (FM). Nevertheless, their effectiveness in removing ARGs varied considerably. During the 31 days of composting, the total removal rates of ARGs were 59.97% (FC) and 76.11% (FM), while the removal rates for class 1 integron (intI1) were 2.31% (FC) and 69.13% (FM). With the exception of tetX, tetG, and tetW, all other ARGs exhibited a rebound during the later stage of the FC process. In contrast, the FM process effectively reduced the risk of ARG rebound during this phase, which can be attributed to its extended thermophilic period and the physical barrier effect of the semi-permeable membrane. Network analysis indicated that ARGs were primarily associated with Bacillota and Pseudomonadota. The Partial Least Squares Path Model (PLS-PM) revealed that the bacterial community was the main factor influencing ARG dynamics in FC, while in FM, both the bacterial community and intI1 were the primary drivers. This study provides critical insights for optimizing composting strategies to prevent the dissemination of antibiotic resistance. Full article

Biogas production through anaerobic digestion is increasingly recognised as a strategic renewable energy pathway capable of addressing South Africa’s energy insecurity, organic waste management challenges, and climate mitigation goals. However, the water-intensive nature of anaerobic digestion raises critical sustainability concerns in water-scarce regions. This systematic review critically examines the water footprint of biogas-based bioenergy systems, with a specific focus on South Africa’s water-stressed context, to understand how water availability, feedstock selection, digester configuration, and governance frameworks influence system viability and scalability. This study adopts a systematic literature review (SLR) approach guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology; peer-reviewed literature published between 2010 and 2025 was retrieved from Scopus and Web of Science and synthesised through descriptive analysis and qualitative meta-synthesis. The review integrates blue, green, and greywater footprint concepts to assess water use across diverse biogas pathways, including livestock manure, agricultural residues, food waste, wastewater sludge, and aquatic biomass. Findings indicate that wet digestion systems, dominant in South Africa, are highly sensitive to freshwater availability, particularly where slurry dilution relies on blue water. In contrast, wastewater-integrated, semi-wet, and co-digestion systems substantially reduce freshwater demand while enhancing methane yields and process stability. The reuse of greywater, industrial effluents, and digestate emerges as a key strategy for lowering water footprints and strengthening circular water–energy linkages. Despite strong technical potential, the adoption of water-efficient anaerobic digestion systems remains constrained by fragmented governance, infrastructure deficits, and limited empirical data on dry and low-water digestion technologies. The review concludes that embedding water footprint considerations into bioenergy planning, policy, and system design is essential for the sustainable expansion of biogas in South Africa. Integrated water–energy–waste governance, coupled with targeted technological innovation, is critical to ensuring that biogas development enhances both energy security and water sustainability in water-scarce regions. Full article

Acidified soils in greenhouse vegetable systems constrain crop production and soil ecological functions. This study investigated the effects of different amendment treatments on soil ecological factors in acidified soils under greenhouse spinach cultivation in Baoqing County, China. Three treatments were established: farmyard manure alone (T1), Haijuneng soil amendment, an alkaline oyster-shell-based soil conditioner, alone (T2), and the combined application of farmyard manure and Haijuneng soil amendment (T3). High-throughput sequencing of the 16S rRNA gene combined with functional prediction was used to analyze soil bacterial community characteristics and their relationships with soil physicochemical properties and enzyme activities. The results showed that soil pH increased significantly under T2 compared with T1 (4.59 vs. 4.14), along with higher exchangeable calcium (16.11 vs. 12.20 cmol kg⁻¹) and exchangeable magnesium (5.54 vs. 3.83 cmol kg⁻¹). In contrast, T3 showed the highest organic matter content (48.54 g kg⁻¹) and phosphatase activity. Compared with T1, both T2 and T3 increased urease activity and altered bacterial community structure and functional composition, while microbial diversity was highest under T2. Soil pH and available phosphorus were the main factors driving bacterial community variation, whereas pH, exchangeable calcium, and exchangeable magnesium were significantly correlated with multiple dominant genera and KEGG level 2 pathways. Overall, the amendment strategies showed distinct effects: compared with the conventional practice of farmyard manure alone, Haijuneng soil amendment alone was more effective in partially alleviating soil acidification, whereas its combined application with farmyard manure was more favorable for soil organic matter accumulation and enhancing soil phosphorus supply potential. Full article

Anaerobic digestion is a key technology for chicken manure valorization, but ammonia accumulation often causes system instability. In this study, a 100-day continuous stirred tank reactor (CSTR) experiment was conducted under mesophilic conditions to investigate the mechanisms of ammonia inhibition in chicken manure at total solids (TS) contents of 8% (T1), 12% (T2), and 16% (T3). Compared to T1, the peak TAN concentrations in T2 and T3 were 64.28% and 73.82% higher. After 100 days, pH in T2 and T3 dropped by 5.19% and 7.65% relative to T1. Volatile fatty acid (VFA) accumulation increased by 4.6- and 6.5-fold, while the TS-based methane yield decreased by 52.94% and 73.11%, respectively. Metagenomic analysis revealed the mechanisms of ammonia inhibition: high-ammonia conditions not only directly suppressed the gene abundance of methanogenic pathways but also systematically reduced the abundance of hydrolytic bacteria and acidogenic fermentative bacteria, leading to a disruption in the supply chain of methanogenic precursors, while ammonia-tolerant microbiota became competitively enriched. This study elucidates the multi-level mechanism of ammonia inhibition in high-TS chicken manure digestion at the functional gene level, providing a theoretical basis for the precise regulation of ammonia stress and improvement of system stability. Full article

(1) Background: We investigated the effects of nutrient levels on rice yield and nitrogen uptake, with the aim of improving rice yield and nitrogen use efficiency. (2) Methods: A 3-year field experiment was conducted using the rice variety Changliangyou Fuxiangzhan, with six treatments: no nitrogen application (CK), conventional fertilization (FP), single basal application of 60-day slow-release urea (CRU1), single basal application of urea combined with 40-day and 90-day slow-release urea (CRU2), partial substitution of chemical fertilizer with bio-organic manure (FPM), and conventional fertilization combined with straw return (FPS). (3) Results: Different nutrient management regimes significantly affected rice yield and nitrogen uptake and use, as well as soil nitrogen content. CRU2 achieved the highest performance across most indicators, with grain yield averaging 9.6% higher than that of FP and 36.4% higher than that of CK, alongside consistently greater effective panicle numbers. It also significantly enhanced nitrogen uptake, with higher grain and straw N accumulation, and showed the best nitrogen use efficiencies. Soil responses varied by treatment: FPS and FPM increased total nitrogen, while CRU2 and CRU1 had the highest inorganic nitrogen, and microbial biomass nitrogen peaked under FPM, CRU2, and FPS. Despite these benefits, CRU2 showed the largest negative nitrogen balance, averaging −33.0 kg ha⁻¹ over 3 years. (4) Conclusions: The CRU2 treatment achieved efficient synchronization between nitrogen supply and demand, with the highest yield, nitrogen uptake, and soil nitrogen levels. Full article

Low ambient temperatures severely restrict the start-up efficiency and microbial bioconversion of livestock manure during aerobic composting. To overcome this “cold-start” barrier, this study investigated the coupled effects of an easily accessible carbon source (molasses) and functional microbial inoculants (Streptomyces griseorubens JSD-1 and Paenarthrobacter nitroguajacolicus LDT1-8) on cattle manure composting. Results demonstrated that the combined strategy significantly expedited thermogenesis, achieving a peak temperature of 62.1 °C and extending the thermophilic phase (>50 °C) by 2 days. This enhanced microbial activity accelerated organic matter stabilization, increasing cellulose and hemicellulose degradation by 44.0% and 49.3%, respectively, and boosting humic acid content by 33.4% in treatment T7 (molasses + JSD-1 + LDT1-8). Amplicon sequencing revealed that the amendments reshaped microbial community structure, selectively enriching lignocellulose degradation and humification-driving taxa (e.g., Actinobacteriota and Mycothermus), leading to a more robust and modular metabolic network. Redundancy analysis confirmed that this directed succession was primarily driven by organic matter degradation and humic fraction accumulation. Overall, the combined application of molasses and microbial inoculants promoted temperature rise, lignocellulose degradation, and humification by reshaping microbial community structure, providing an effective strategy for improving cattle manure composting efficiency under low-temperature conditions. Full article

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