Search Results (62)

China’s livestock farming scale rose from 54.4% in 2020 to 73.2% in 2023, increasing annual manure production to 3.8 billion tons and greenhouse gas emissions to 4–6 billion t carbon dioxide equivalent (CO₂-eq). Manure management has thus become a key barrier to agricultural pollution control and carbon reduction goals. This study analyses regional differences in manure generation, showing that East and Central China—comprising less than 40% of the national land area—bear over 48% of total manure and about 50% of N and P loads, whereas Northeast and Northwest China have surplus cropland absorption capacity. This reveals a clear spatial mismatch between manure production and land carrying capacity. By reviewing major treatment technologies (aerobic composting, anaerobic digestion) and utilisation pathways (fertiliser use, energy recovery) and integrating life cycle assessment (LCA) with geographic information system (GIS)-based spatial evaluation, this study highlights the advantages of technology coupling strategies. For example, anaerobic digestion combined with composting can reduce net climate impacts by 21%, and regional circular models cut full-cycle carbon footprints by 34.44%. The results underscore the need for GIS-supported spatial LCA to match technologies with regional conditions, providing a scientific basis for advancing livestock manure management and China’s green agricultural transition. Full article

Phosphorus (P) is a vital macronutrient involved in key biochemical processes that support plant growth; however, its low bioavailability in agricultural soils remains a major constraint on crop productivity. This limitation is commonly addressed through the application of chemical P fertilisers produced by acidulation of phosphate rock (PR), a process that is costly, energy-intensive, and environmentally hazardous. This study evaluated the P-solubilising potential of culture filtrates from three fungal strains (Aspergillus flavus JKJ7, Talaromyces purpureogenus JKJ12, and Trichoderma koningiopsis JKJ18) grown in National Botanical Research Institute’s Phosphate (NBRIP) liquid medium supplemented with tricalcium phosphate (TCP), and compared their TCP solubilisation efficiency with that of pure acids (citric and sulfuric acid). All three fungal strains solubilised TCP in NBRIP medium, with A. flavus JKJ7 producing the highest concentration of soluble P (259.81 mg L⁻¹), followed by T. koningiopsis JKJ18 (166.41 mg L⁻¹) and T. purpureogenus JKJ12 (47.07 mg L⁻¹). Soluble P concentrations were inversely correlated with pH and positively correlated with titratable organic acidity (TOA). High-performance liquid chromatography (HPLC) identified citric, succinic, tartaric, and gluconic acids as the dominant organic acids associated with P solubilisation. In pure acid treatments, sulfuric acid exhibited concentration-dependent increases in soluble P, whereas citric acid showed reduced solubilisation efficiency at higher concentrations. Although fungal culture filtrates achieved lower maximum TCP solubilisation than strong mineral acids, their higher TOA contributed to improved stabilisation of soluble P by limiting calcium-mediated reprecipitation. These findings demonstrate that crude fungal organic acid mixtures can complement or partially substitute inorganic acids for mobilising P from low-reactivity PR, offering a potentially cost-effective and environmentally sustainable alternative for P fertiliser production. This study supports the development of biologically derived P inputs aligned with circular bioeconomy and sustainable agriculture goals. Full article

Anaerobic digestate (AD) has the potential to partially replace inorganic fertiliser, containing readily available nitrogen and other macro- and micronutrients. However, these properties vary with the feedstock. The objectives of this study were to analyse the chemical composition of AD materials and measure their effects on plant growth and greenhouse gas emissions. Anaerobic digestate came from a conventional reactor using vegetable waste and maize as feedstock (‘food AD’) and from a biogas system on a smallholder dairy farm using manure feedstock (‘manure AD’). Undigested cattle slurry (‘manure slurry’) and a complete mineral fertiliser were used as controls. These were applied to wheat plants grown in a glasshouse. Wheat grown with the food AD had a higher yield than the complete mineral fertiliser control, even when applied at a lower rate of nitrogen. Wheat grown with both the food AD and manure AD had macronutrient concentrations equal to or higher than the complete mineral fertiliser treatment. Furthermore, the wheat P concentration was significantly greater with the manure AD treatment, which was unrelated to a biomass dilution effect. However, food AD caused high ammonia emissions, and residual methane was emitted with manure AD, indicating incomplete digestion in the latter. Optimal yields and reduced greenhouse emissions were obtained with mixtures of AD and mineral fertiliser in a 1:1 ratio, indicating the potential to greatly reduce the costs and environmental impact of fertiliser application. Full article

This study evaluates the environmental outcomes of integrating anaerobic digestion (AD) with pyrolysis (Py) and hydrothermal carbonization (HTC) to treat cattle slurry and grass silage in an Irish agricultural context. A consequential life cycle assessment (CLCA) was carried out for six scenarios based on 1 t of feedstock (0.4:0.6 cattle slurry/grass silage on a VS basis): two standalone AD systems (producing bioelectricity and biomethane) and four integrated AD–Py/HTC systems with different product utilisation pathways. Across all impact categories, the integrated systems performed better than standalone AD. This improvement is mainly due to the surplus bioenergy (electricity, biomethane, hydrocarbon fuel, hydrochar) that replaces marginal fossil energy (hard coal, natural gas and heavy fuel oil), together with the displacement of mineral NPK fertilisers by digestate-derived biochar and HTC process water. Among the configurations, the AD–HTC bioelectricity scenario (S4) achieved the best overall performance, driven by higher hydrochar yields, a favourable heating value, and a lower pretreatment energy demand compared with Py-based options. Across the integrated scenarios, climate change, freshwater eutrophication, and fossil depletion impacts were reduced by up to 84%, 86%, and 99%, respectively, relative to the fossil-based reference system, while avoiding digestate and fertiliser application reduced terrestrial acidification by up to 74%. Overall, the results show that the cascading utilisation of digestate via AD–Py/HTC can simultaneously enhance bioenergy production and nutrient recycling, providing a robust pathway for low-emission management of agricultural residues. These findings are directly relevant to Ireland’s renewable energy and circular economy targets and are transferable to other livestock-intensive regions seeking to valorise slurry and grass-based residues as low-carbon energy and biofertiliser resources. Full article

Bio-based fertilisers (BBFs) derived from waste streams represent a transformative approach to sustainable agriculture, addressing the dual challenges of waste management and food security. This comprehensive review examines recent advances in BBF production technologies, nutrient recovery mechanisms, soil health impacts, and the benefits of a circular economy. This review, based on an analysis of peer-reviewed studies, demonstrates that BBFs consistently improve the physical, chemical, and biological properties of soil while reducing environmental impacts by 15–45% compared to synthetic alternatives. Advanced biological treatment technologies, including anaerobic digestion, vermicomposting, and biochar production, achieve nutrient recovery efficiencies of 60–95% in diverse waste streams. Market analysis reveals a rapidly expanding sector projected to grow from $2.53 billion (2024) to $6.3 billion by 2032, driven by regulatory support and circular economy policies. Critical research gaps remain in standardisation, long-term performance evaluation, and integration with precision agriculture systems. Future developments should focus on AI-driven optimisation, climate-adaptive formulations, and nanobioconjugate technologies. Full article

Excess nutrients in wastewater pose significant environmental risks, highlighting the need for low-cost treatment strategies that enable their removal. This study evaluated the adsorption capacity of woodchip biochar, a widely available waste material, for phosphate (PO₄³⁻), nitrate (NO₃⁻), and ammonium (NH₄⁺) in raw and secondary-treated wastewater, and compared the results against those obtained using synthetic solutions. Approach to equilibrium was reached quicker for NH₄⁺ (≈20 min) than for NO₃⁻ and PO₄³⁻ (≈40 min), with NH₄⁺ removal reaching up to 80% at a dosage of 20 g/L. Nutrient adsorption kinetics were best described by the pseudo-second-order model for the anionic species (NO₃⁻ and PO₄³⁻), while the pseudo-first-order model provided a better fit for the cationic species NH₄⁺. The Freundlich isotherm provided a good fit to the equilibrium data for all species, indicating the presence of heterogeneous adsorption sites. SEM–EDX and FTIR analyses confirmed nutrient adsorption onto the biochar surface and highlighted the involvement of carboxyl and hydroxyl functional groups, with FTIR showing the greatest spectral changes for NH₄⁺. Adsorption tests using secondary-treated wastewater showed high removal efficiencies (100% PO₄³⁻, 25.4% NO₃⁻, 89.5% NH₄⁺), whereas performance in raw wastewater was poor (maximum 32% NH₄⁺). Overall, woodchip biochar demonstrates strong potential as a tertiary treatment material, and its nutrient-saturated form may be reused as fertiliser, supporting nutrient recovery within a circular-economy framework. Full article

This study examined how different fertilisation strategies (mineral, compost, vermicompost and non-fertilised control) influence vine nutrient status, must composition and wine chemical characteristics over two consecutive seasons (2024–2025) in two semi-arid Mediterranean vineyards, one deficit-irrigated and other rainfed. Compost and vermicompost were produced from winery residues, in line with a circular management approach. Organic fertilisation improved vine nitrogen and potassium levels, particularly at veraison, with cumulative effects observed over time. Musts from fertilised vines (mineral, compost and vermicompost) exhibited higher levels of yeast-assimilable nitrogen (YAN) and pH, as well as lower titratable acidity, compared to the control group (without fertilization). Wines obtained from these treatments exhibited higher ethanol content and modified acidity parameters, with compositional changes being more evident in the rainfed vineyard. Analysis of volatile compounds revealed that organic fertilisers, particularly vermicompost, promoted the formation of esters, higher alcohols, and terpenes linked to grape metabolism and fermentation. These results demonstrate that organic amendments derived from winery waste can serve as efficient nutrient sources, thereby enhancing the nutritional balance of vines and the composition of wines, while also promoting sustainable and circular practices in viticulture. Full article

Bio-based fertilisers (BBFs), produced from various types of biological waste using different processing methods, have demonstrated encouraging levels of agronomic efficiency and environmental benefits, consistent with the principles of sustainable development (SD). Nevertheless, bringing these newly developed products to market remains difficult due to limited farmer awareness, perceived risks, and regulatory uncertainties. In this paper, we examine the attitudes, opinions, and awareness of farmers regarding the use of various BBFs in their fertilisation practices. We applied a survey research method, using the Paper and Pen Personal Interview (PAPI), and answers were collected by agricultural advisors. A questionnaire, consisting of open, closed, and Likert scale questions, focusing on general information about farmers, current practices regarding fertiliser use, and the determinants of fertiliser choice, was used. Descriptive statistics, cross-tabulations, chi-square tests, Cramer’s V coefficients, 95% confidence intervals, and McNemar’s test were used to analyse the data. This study was conducted in all 16 voivodeships in Poland, collecting a total of 800 responses. Factors influencing the negative or positive attitude of farmers toward this practice were identified. Currently, mineral fertilisers remain the dominant choice among Polish farmers due to their accessibility, cost-effectiveness, and agronomic performance. There is observed growing, albeit cautious, interest in alternative fertilisation strategies and the correct understanding of sustainable agriculture practices. About half of farmers expressed willingness to partially replace mineral fertilisers with organic options, but only a minority showed interest in adopting BBFs. The findings indicate that concerns about contaminants, heterogeneous quality, limited availability, and regulatory uncertainty continue to constrain interest in BBFs. Although respondents recognised potential environmental benefits, economic and agronomic considerations remained the primary drivers of decision-making. As the survey was conducted in late 2021, the results reflect pre-2022 market conditions and should be interpreted as a baseline rather than a direct indication of current attitudes. Overall, this study provides insights into behavioural and structural factors influencing fertiliser use in Poland and highlights areas where further policy, advisory, and market developments may help support more sustainable nutrient management. Full article

Composting seaweed biomass reduces environmental impacts while supporting circular-economy strategies in coastal areas, where seaweed removed for recreational management is commonly treated as waste. This approach aligns with regional and EU policies on circular bioeconomy and coastal ecosystem restoration. This study evaluated the effects of Mar Menor seaweed compost applied at 0%, 15% and 35% on lettuce cultivation. Two nitrogen supply levels (100% and 60%) were also used to assess interactive effects on plant growth and nutrient dynamics. The optimal rate of 15% compost enhanced lettuce growth by 25.1% under 100% N irrigation and by 32.2% under 60% N irrigation, indicating that reduced nitrogen availability did not limit biomass accumulation. Indeed, irrigation nitrogen level did not affect total biomass. Compost addition also improved nutrient content and increased phenolic compounds in leaves. When nitrogen was reduced, the combination with compost further boosted phenolic accumulation, by 39.6% with 15% compost and 34.7% with 35%, suggesting a synergistic response. Overall, seaweed compost improves crop performance and nutritional quality while lowering dependence on synthetic fertilisers. Environmentally and economically, it provides coastal municipalities a sustainable option for managing excess seaweed by converting waste into valuable agricultural inputs and mitigating impacts of algal overgrowth. Full article

Advanced phosphorus (P) recycling from wastewater is critical for improving nutrient circularity and reducing soil pollution associated with the direct application of sewage sludge in agriculture. However, few studies evaluate the long-term environmental and economic trade-offs between recycled P products and raw sewage sludge application. This study compares struvite, vivianite, and dicalcium phosphate (CaP) as P alternatives to sludge to mitigate heavy metal accumulation in Spanish agricultural soils. Using data from 27,835 plots, heavy metal accumulation was simulated over 50- and 100-year fertilisation scenarios. The results indicate that continuous sludge application leads to widespread exceedances of zinc, copper, and cadmium, especially in alkaline soils, whereas substitution with recycled products can substantially reduce these risks. Vivianite balances P recycling and costs, CaP offers the best environmental performance but with higher investment, and struvite suits smaller regions prioritising environmental safety. Economic analysis favours advanced recycling over sludge, especially considering externalities such as soil remediation costs. Despite limitations, our findings emphasise the importance of integrating environmental externalities into economic assessments and the value of advanced P recycling for sustainable soil management. Full article

This review examines the current status and future potential of plasma-induced acidification (PIA) as a sustainable method for managing nitrogen-rich organic waste streams such as livestock slurry and digestate. Conventional acidification using sulfuric or nitric acid reduces ammonia (NH₃) emissions but raises concerns related to safety, cost, and environmental impacts. Plasma-assisted systems offer an alternative by generating reactive nitrogen and oxygen species (RNS/ROS) in situ, lowering pH and stabilizing ammonia (NH₃), as ammonium (NH₄⁺), thereby enhancing fertiliser value and reducing emissions of NH₃, methane (CH₄), and odours. Key technologies such as dielectric barrier discharge (DBD), corona discharge, and gliding arc reactors show promise in laboratory-scale studies, but barriers like energy consumption, scalability, and N₂O trade-offs limit commercial adoption. The paper reviews the mechanisms behind PIA, compares it to conventional approaches, and assesses its agronomic and environmental benefits. Valorisation opportunities, including the recovery of nitrate-rich fractions and integration with biogas systems, align plasma treatment with circular economy goals. However, challenges remain, including reactor design, energy efficiency, and lack of recognition as a Best Available Technique (BAT). A roadmap is proposed for transitioning from lab to farm-scale application, involving cross-sector collaboration, lifecycle assessments, and policy support to accelerate adoption and realise environmental and economic gains. Full article

Bio-based fertilisers (BBFs) are gaining attention as sustainable alternatives to mineral fertilisers due to their potential for nutrient recovery, reduced environmental emissions, and improved soil health. However, their broader adoption is hindered by regulatory uncertainty, quality inconsistencies, and methodological variability in assessing their environmental impacts. This study can reveal about the body of research on bio-based fertilisers (BBFs), using a hybrid methodology that combines bibliometric and content analysis. A total of 247 publications from 2001 to 2024 were reviewed to identify research trends, environmental concerns, and assessment approaches. Results show a sharp increase in BBF-related publications after 2016, driven primarily by European and North American research, with growing focus on life cycle assessment (LCA) and nutrient recovery. The in-depth analysis of the ten most cited LCA and non-LCA studies highlights key methodological differences: non-LCA studies frequently rely on empirical fieldwork and generate primary data, whereas LCA studies typically synthesise secondary data to provide broader system-level insights. Despite this complementarity, the lack of methodological harmonisation poses a barrier to consistent comparison and interpretation. The findings highlight the need for a unified, standardised assessment framework to reliably evaluate the environmental performance of BBFs and support their effective implementation within circular and sustainable agricultural systems. Full article

Global concerns about resource depletion, climate change, and nutrient pollution in aquatic systems are compelling a transition towards zero-waste industries. With the skyrocketing carbon footprint of the modern fertiliser industry, sustainable options are highly sought after. Anaerobic digestion of organic waste to generate renewable biogas and fertiliser production from the residual nutrient-rich digestate are promising nutrient recovery and recycling avenues. This review explores the potential use of anaerobic digestate to develop value-added agronomic products, focusing on the quality and safety parameters pivotal to its fertiliser value. A comprehensive review of conventional and cutting-edge technologies available for digestate processing into organic/organo-mineral fertilisers has been conducted, highlighting emerging sustainable approaches. Specifically, this review unravels novel aspects of enhancing digestate quality with biostimulants such as plant growth-promoting rhizobacteria, humic substances and biochar for biofertiliser/slow-release fertiliser production. Additionally, methods and guidelines to assess and address environmental impacts by digestate application on croplands and challenges in the commercialisation of digestate-based fertilisers were analysed. This review also underscores the importance of valorising anaerobic digestate as a fertiliser in implementing a circular bioeconomy within the agroindustry. Full article

While mechanical dewatering is widely used in faecal sludge treatment, the agricultural potential of mechanically dewatered faecal sludge (MDFS) combined with anaerobic digestion (AD) remains underexplored, particularly in sub-Saharan Africa where nutrient recovery is critical for food security. This study provides the first comprehensive characterisation of MDFS from Ghana’s largest treatment facility and evaluates anaerobic digestion effectiveness for agricultural application. Over six months, 182 composite MDFS samples from Lavender Hill Faecal Treatment Plant were analysed for physicochemical properties, nutrients, heavy metals, and microbial contaminants before and after AD treatment. MDFS demonstrated exceptional nutrient density, with total nitrogen (2141.05 mg/kg), phosphorus (190.08 mg/kg), and potassium (4434.88 mg/kg) concentrations comparable to commercial organic fertilisers. AD achieved significant pathogen reduction, decreasing total coliforms from 148,808.70 to 493.33 cfu/100 g (p < 0.001) and Ascaris lumbricoides eggs from 12.08 to 3.33 eggs/L, while maintaining nutrient integrity and keeping heavy metals within safe agricultural limits. Statistical modelling revealed a significant correlation between treatment duration and pathogen reduction efficiency. Despite substantial improvements, treated MDFS still exceeded some regulatory thresholds, indicating a need for complementary post-treatment strategies. This research establishes AD as an effective primary treatment for converting MDFS into a nutrient-rich organic fertiliser, supporting circular economy principles in urban sanitation systems and providing a sustainable pathway for agricultural nutrient recovery in resource-constrained settings. Full article