Search Results (675)

Carbon farming represents a strategic approach to enhancing agricultural sustainability while reducing greenhouse gas (GHG) emissions. In Türkiye, agriculture accounted for approximately 14.9% of national GHG emissions in 2023, dominated by methane (CH₄) and nitrous oxide (N₂O). By increasing carbon storage in soils and vegetation, carbon farming can improve soil health, water retention, and climate resilience, thereby contributing to mitigation efforts and sustainable rural development. This study reviews and synthesizes international and national evidence on carbon farming mechanisms, practices, payment models, and adoption enablers and barriers, situating these insights within Türkiye’s agroecological and institutional context. The analysis draws on a systematic review of peer-reviewed literature, institutional reports, and policy documents published between 2015 and 2025. The findings indicate substantial mitigation potential from soil-based practices and livestock- and manure-related measures, yet limited uptake due to low awareness, capacity constraints, financial and administrative barriers, and regulatory gaps, highlighting the need for region-specific approaches. To support implementation and scaling, the study proposes a policy-oriented, regionally differentiated and digitally enabled MRV framework and an associated implementation pathway designed to reduce transaction costs, enhance farmer participation, and enable integration with emerging carbon market mechanisms. Full article

Pasture-based ruminant systems link nitrogen (N) nutrition with ecosystem N cycling. Grazing ruminants convert fibrous forages into milk and meat but excrete 65 to 80% of ingested N, creating excreta hotspots that drive ammonia volatilization, nitrate leaching, and nitrous oxide (N₂O) emissions. This review synthesizes ecological and ruminant nutrition evidence on N flows, emphasizing microbial processes, biological N₂ fixation, plant diversity, and urine patch biogeochemistry, and evaluates strategies to improve N use efficiency (NUE). We examine rumen N metabolism in relation to microbial protein synthesis, urea recycling, and dietary factors including crude protein concentration, energy supply, forage composition, and plant secondary compounds that modulate protein degradability and microbial N capture, thereby influencing N partitioning among animal products, urine, and feces, as reflected in milk and blood urea N. We also examine how grazing patterns and excreta distribution, assessed with sensor technologies, modify N flows. Evidence indicates that integrated management combining dietary manipulation, forage diversity, targeted grazing, and decision tools can increase farm-gate NUE from 20–25% to over 30% while sustaining performance. Framing these processes within the global N cycle positions pasture-based ruminant systems as critical leverage points for aligning ruminant production with environmental and climate sustainability goals. Full article

Agricultural soils are the largest anthropogenic source of nitrous oxide (N₂O), primarily due to excessive nitrogen (N) fertilization and inefficient N management. Mitigating N₂O emissions from croplands without compromising productivity is therefore a major global challenge for climate and environmental sustainability. A three-year split-plot field experiment was conducted in an arid maize production region of northwestern China to examine how green manure intercropping combined with reduced chemical N input regulates N₂O emissions and soil N residues. The main plots comprised maize monoculture (M), maize intercropped with common vetch (M/V), and maize intercropped with rape (M/R), while subplots consisted of local conventional N application (N1: 360 kg N ha⁻¹) and a 25% reduced rate (N2: 270 kg N ha⁻¹). Results indicated that intercropping with green manure can offset the reduction in maize grain yield caused by a 25% decrease in N supply. Green manure intercropping significantly decreased cumulative N₂O emissions compared with monoculture maize, and the mitigation effect was further strengthened under reduced N input. The M/V system under reduced N input exhibited the strongest mitigation effect, reducing N₂O emissions per unit of grain yield by 9.2–11.5% compared with the M/R system. This reduction was driven by the ability of M/V to stabilize soil mineral N availability. Notably, the independent maize growth stage contributed 52.6–66.9% of total seasonal N₂O emissions, emphasizing it as a critical period for emission mitigation. Overall, integrating green manure intercropping with reduced chemical N input effectively mitigates N₂O emissions while maintaining maize productivity in arid regions, providing a practical strategy for sustainable and environmentally responsible agricultural intensification. Full article

Antibiotic resistance genes (ARGs) pose a serious threat to the environment worldwide. The guts of soil animals are a hotspot for ARGs and denitrification in soils. However, it is unclear how denitrification affects the spread of ARG in the earthworm’s gut. In this study, the typical soil earthworm Pheretima guillelmi was employed, and was used for performing anoxic incubation with gut content amended with nitrate and nitrite. To analyze the data, a combination of chemical analysis, 16S rRNA-based Illumina sequencing, and high-throughput qPCR were employed. Nitrate treatments, particularly at 5 mM, caused substantial reductions in nitrate concentrations, with a corresponding increase in nitrite, nitrous oxide (N₂O), and nitric oxide (NO) emissions compared to the treatments with the addition of 1 and 2 mM nitrate. Nitrite (0.2, 0.5 and 1 mM) amendments also enhanced the accumulation of nitrogen intermediates. Organic acid production, including acetate and pyruvate, was the highest under the 5 mM nitrate treatment. This treatment also promoted the highest level of glucose utilization, suggesting that glucose metabolism supports enhanced organic acid production. Both nitrate and nitrite treatments exhibited the pronounced enrichment in ARGs, particularly for beta-lactam and multidrug resistance genes. Denitrifying bacteria such as Aeromonas, Bacillus, Raoultella, and Enterobacter were identified as key hosts for these ARGs. These results emphasized that denitrifying bacteria play a pivotal role in the horizontal transfer of ARGs, underscoring the need for careful nitrogen management in agricultural practices to control the spread of antibiotic resistance in natural environments. Full article

Nutrient additions including nitrogen (N) and phosphorus (P) are widely considered as an important strategy for enhancing grassland productivity. However, the effects of these nutrients additions on soil nitrous oxide (N₂O) emissions and the underlying mechanisms remain debated. We conducted a two-year field experiment in an alpine grassland on Kunlun Mountain in northwestern China to assess the effects of N and P additions on N₂O emissions, in relation with nitrifying enzyme activity (NEA), denitrifying enzyme activity (DEA), and key functional genes abundance responsible for nitrification (amoA and Nitrobacter-like nxrA) and denitrification (narG, nirS, nirK and nosZ). Compared to the Control without nutrient addition (CK), N addition alone substantially increased cumulative N₂O emission (ƩN₂O) by 2.0 times. In contrast, P addition or combined N and P (N+P) addition did not significantly affect ƩN₂O, though both treatments significantly increased plant aboveground biomass. Such results indicate that P addition may mitigate N-induced N₂O emission, likely by reducing soil N availability through enhanced plant and microbial N uptake. Compared to CK, N or N+P addition significantly elevated NEA but did not affect DEA. Structural equation modeling (SEM) indicated that NEA was directly influenced by the gene abundances of ammonia-oxidizing bacteria (AOB) and Nitrobacter-like nxrA but not by ammonia-oxidizing archaea (AOA). However, SEM also revealed that soil environmental variables including soil temperature, pH, and water-filled pore space (WFPS) had a stronger direct influence on N₂O emissions than the abundances of nitrifiers. These results demonstrate that soil environmental conditions play a more significant role than functional gene abundances in regulating N₂O emissions following N and P additions in semi-arid alpine grasslands. This study highlights that the N+P application can potentially decrease N₂O emissions than N addition alone, while increasing productivity in the alpine grassland ecosystems. Full article

Permafrost is an important carbon pool for terrestrial ecosystems and a significant source of atmospheric greenhouse gases, but the effects of ground vegetation and snow cover on permafrost greenhouse gas fluxes are still unclear. The soil–atmosphere exchange fluxes of greenhouse gases (mainly carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O)) occupy key roles during the winter snow and the vegetation growing seasons. Here, a typical Larix gmelinii forest, located in the permafrost region of the Daxing’an Mountains, northeast China, was studied. Using the static chamber-gas chromatograph method, the relationship between soil greenhouse gas emissions, ground vegetation, and snow cover was investigated. We found that the CO₂, CH₄, and N₂O cumulative fluxes from vegetative soils had increased by 19.5%, 37.5%, and 10.7%, compared with fluxes from areas where the ground vegetation had been removed. Snow cover increased soil CO₂ cumulative flux by 53.1% and soil N₂O cumulative flux by 28.6%, and soil CH₄ cumulative flux decreased by 39.3%. Our results show that snow cover and ground vegetation removal reduce CO₂ and N₂O emissions from permafrost soils. Ground vegetation removal also increases the absorption of CH₄ in permafrost soils, while snow cover removal promotes CH₄ emissions. These findings confirm the effects of ground vegetation and snow cover on the transformation processes of greenhouse gases from forest ecosystems in permafrost regions. Therefore, this research provides scientific data support for the improvement of land surface climate models and the mitigation of climate change in cold regions. Full article

Aquaculture systems face escalating ecological risks due to the widespread use and persistence of antibiotics, which disrupt microbial-mediated nitrogen cycling and exacerbate greenhouse gas (GHG) emissions. This review synthesizes the recent research on how common antibiotics, such as sulfonamides, quinolones, tetracyclines, and macrolides, with the concentration ranging from μg/L to mg/L, alter microbial community structure, functional gene expression (e.g., amoA, nirK, and nosZ), and key nitrogen transformation processes. These disruptions inhibit nitrogen-removal efficiency by 25–55%, promote the accumulation of toxic intermediates (e.g., NH₄⁺ and NO₂⁻), and enhance emissions of potent GHGs of nitrous oxide (N₂O) and methane (CH₄). The effects are influenced by antibiotic type; concentration; environmental conditions; and interactions with co-contaminants such as heavy metals (Cu²⁺ and Pb²⁺ at 50–200 μg/L) and microplastics (0.1–10 mg/L), which can synergistically amplify ecological risks by 20–40%. The research in this field has largely focused on the toxicity of individual antibiotics, so significant gaps remain regarding combined pollution effects, long-term microbial adaptation, and molecular-scale mechanisms. This review synthesizes research on the impacts of aquaculture antibiotics on microbial nitrogen cycling and GHG emissions, identifying key mechanisms and research gaps. Its significance lies in laying a scientific foundation for integrated antibiotics pollution control strategies and bridging basic research with practical aquaculture management to advance the sustainability of aquaculture ecosystems. Full article

Piggery farming is the largest source of livestock manure in South Korea, yet greenhouse gas (GHG) data from piggery wastewater treatment systems remain limited. This study quantified methane (CH₄) and nitrous oxide (N₂O) fluxes from a full-scale treatment facility to develop stage-, seasonal-, and diurnal-specific emission factors. Continuous laser-based monitoring using a PVC air-pool chamber was applied across raw wastewater storage, an anoxic nitrogen-conversion reactor, and strongly aerated nitrification units. Mean CH₄ fluxes ranged from 1.1 to 15.6 mg s⁻¹ m⁻² peaking in summer, while N₂O fluxes ranged from 0.01 to 17,971 mg s⁻¹ m⁻², with maxima in fall. Emissions were dominated by two functional zones: aerated basins where vigorous mixing enhanced CH₄ stripping, and an upstream anoxic reactor where oxygen instability and nitrite accumulation produced extreme N₂O peaks. Derived emission factors were 0.11 kg CH₄ head⁻¹ yr⁻¹ and 45.2 kg N₂O head⁻¹ yr⁻¹, equivalent to 3.1 and 12,300 kg CO₂-eq head⁻¹ yr⁻¹. CH₄ variability was controlled mainly by treatment stage and temperature, whereas N₂O was governed by internal redox conditions. These results refine emission factors for inventories and underscore the need for improved aeration stability and denitrification control to reduce GHG emissions from piggery wastewater systems. Full article

Acidic agricultural soils are frequently challenged by co-occurring heavy metal contamination and greenhouse gas (GHG) emissions. While biochar is widely used for integrated remediation, the specific role of silicon (Si) in modulating its effectiveness in cadmium (Cd) stabilization and nitrous oxide (N₂O) mitigation remains insufficiently understood. This study evaluated the co-remediation efficacy of two types of high-Si (bamboo leaves, ML; rice straw, RS) and two types of low-Si (Camellia oleifera leaves, CL; Camellia oleifera shells, CS) biochar, produced at 450 °C, within a Cd-contaminated and nitrogen-fertilized acidic soil. Results from a 90-day incubation showed that while all biochar effectively immobilized Cd, the low-Si CL biochar exhibited a superior stabilization efficiency of 66.2%. This enhanced performance was attributed to its higher soil organic carbon (SOC) and moderate dissolved organic carbon (DOC) release, which facilitated robust Cd²⁺ sorption and complexation. In contrast, high-Si biochar was more effective in mitigating cumulative N₂O emissions (up to 67.8%). This mitigation was strongly associated with an elevated abundance of the nosZ gene (up to 48.1%), which catalyzes the terminal step of denitrification. Soil pH and DOC were identified as pivotal drivers regulating both Cd bioavailability and N₂O dynamics. Collectively, low-Si biochar is preferable for Cd stabilization in acidic soils, whereas high-Si biochar is more effective at elevating pH and reducing N₂O emissions. These findings emphasize that optimizing co-remediation outcomes necessitates a targeted approach, selecting biochar based on the specific contamination profile and desired environmental benefits. Full article

Forest fine root litter enters agricultural soils in some cases and its decomposition would change the soil’s properties. However, how this process further influences the ammonia (NH₃) volatilization and nitrous oxide (N₂O) emission from agricultural soil receiving fertilizer nitrogen (N) is unknown. Here, we conducted a soil pot experiment to investigate the responses of the aforementioned gaseous N losses during wheat season to fine root litters derived from Populus deltoides (RP) and Metasequoia glyptostroboides (RM) incorporations. The results showed that two forest fine root litters reduced total NH₃ losses by 30.6−31.9% from 180 kg N ha⁻¹ applied to farmland soil, and this effect was attributed to decreased soil urease activity and ammonium-N during the basal N fertilization period. Whether receiving fertilizer N or not, N₂O emissions from farmland soil were significantly (p < 0.05) mitigated by 62.8–68.2% and 43.0−50.0% following the RP and RM incorporation, respectively. Lower N₂O emission was ascribed to increased soil pH but decreased soil nitrate-N and bulk density. In addition, less AOA and AOB amoA but more nosZ gene abundances explained the fine root litter-induced N₂O mitigation effect. Neither forest fine root litter exerted a negative effect on wheat grain yield and crop N use efficiency in N-added agriculture soil. In conclusion, forest fine root litter incorporation could help to mitigate gaseous N losses via NH₃ volatilization and N₂O emission from fertilizer-N-applied agricultural soils, and without crop production loss. Full article

Background: Municipal solid waste management is a relevant component of climate and air quality policy, yet published life cycle assessments report inconsistent conclusions on whether sanitary landfilling, waste-to-energy incineration, composting, or anaerobic digestion yields the lowest greenhouse gas and co-pollutant impacts because results depend strongly on methodological choices and local context. Objective: To synthesize and critically evaluate how key life cycle assessment assumptions and boundary decisions influence reported emissions across major waste management pathways, with primary emphasis on the United States and selected comparison to European Union policy frameworks. Methods: Peer-reviewed life cycle assessment studies and supporting technical and regulatory sources were reviewed and compared, focusing on functional unit definition, system boundaries, time horizon, energy substitution and crediting methods, and treatment of methane, nitrous oxide, and air pollutant controls; drivers of variability were identified through structured cross study comparison and sensitivity-focused interpretation. Results: Reported pathway rankings vary primarily with landfill gas collection and utilization assumptions, the carbon intensity of displaced electricity or heat for waste-to-energy systems, and the representation of biological process emissions across active and curing stages; harmonized comparisons reduce variability but do not yield a single consistently superior pathway across all plausible settings. Conclusions: Comparative conclusions are context-dependent and policy-relevant interpretation requires transparent reporting and sensitivity analysis for capturing efficiency, substitution factors, and biological emission controls, along with clear alignment between modeled scenarios and real-world operating conditions. Full article

Greenhouse gas emissions from agricultural crops remain a critical challenge for climate change mitigation. This review synthesizes evidence on cropland management interventions and global N₂O mitigation potential. Agricultural practices such as cover cropping, agroforestry, reduced tillage, and diversification show promise in reducing CO₂, CH₄, and N₂O emissions, yet uncertainties in measurement, verification, and socio-economic adoption persist. This review highlights that biochar application reduces N₂O emissions by 16.2% (95% CI: 9.8–22.6%) in temperate systems, demonstrating greater consistency compared to no-till agriculture, which shows higher variability (11% reduction, 95% CI: −19% to +1%). Legume-based crop rotations reduce N₂O emissions by up to 39% through improved nitrogen efficiency and increase soil organic carbon by up to 18%. However, reductions in synthetic fertilizer use (65% lower in legume vs. cereal systems) can be offset by the effects of biological nitrogen fixation. Optimized nitrogen fertilization, when combined with enhanced-efficiency fertilizers, can reduce N₂O emissions by 55–64%. Complementing this, global-scale analysis underscores the dominant role of optimized nitrogen fertilization in curbing N₂O emissions while sustaining yields. To bridge gaps between practice-level interventions and global emission dynamics, this paper introduces the ICEMF, a novel approach combining field-based management strategies with spatially explicit emission modeling. Realistic implementation currently achieves 25–35% of technical potential, but bundled interventions combining financial incentives, training, and institutional support can increase adoption to 40–60%, demonstrating ICEMF’s value through integrated, context-adapted approaches. Only peer-reviewed articles published in English between 1997 and 2025 were selected to ensure recent and reliable findings. This review highlights knowledge gaps, evaluates policy and technical trade-offs, and proposes ICEMF as a pathway toward scalable and adaptive mitigation strategies in agriculture. Full article

Maritime transport accounts for approximately 80–90% of global trade and nearly 3% of global greenhouse gas (GHG) emissions. In response, the International Maritime Organization (IMO) adopted an ambitious strategy for net-zero emissions by 2050, critically mandating a Well-to-Wake (WtW) life-cycle assessment for fuels. This framework invalidates fuels produced with high carbon intensity, regardless of their emissions at the point of use, thereby compelling the industry to focus on truly clean and sustainable alternatives. This push positions green hydrogen and ammonia as leading solutions, though they present a distinct trade-off. Hydrogen is an ideal fuel with zero-carbon emission in fuel cells but faces significant storage challenges due to its extremely low volumetric energy density and cryogenic requirements. In contrast, ammonia offers superior energy density and easier handling but contends with issues of toxicity and potentially harmful emissions like nitrous oxide. This paper provides a comprehensive review of this complex landscape, analyzing the production, utilization, and associated techno-economic and geopolitical challenges of using hydrogen and ammonia as future marine fuels, with environmental aspects briefly considered. Full article

Drip fertigation (DF) is a sustainable agricultural management technique that optimizes water and nutrient usage, enhances crop productivity, and reduces environmental impact. Herein, we compared the effects of DF and conventional fertilization (CF) with a basal fertilizer on yield, soil inorganic nitrogen dynamics, N₂O emissions, and nitrogen leaching during facility-grown eggplant cultivation. The experiment was conducted in a greenhouse from September 2023 to May 2024, with treatments arranged in three rows and three replicates. Soil, gas, and water samples were collected and analyzed throughout the growing season. The results revealed that the DF treatment produced yields comparable to those obtained with the CF treatment while significantly reducing nitrogen and phosphorus inputs. DF effectively prevented excessive nitrogen accumulation in the soil and reduced nitrogen loss through leaching and gas emissions. N₂O emissions were significantly lower by more than 60% under DF than under CF. Precise nutrient management in DF suppressed nitrification and denitrification processes, mitigating N₂O emissions. DF also significantly reduced nitrogen leaching by more than 70% compared with that in CF. These findings demonstrate that DF effectively enhances agricultural sustainability by improving nutrient use efficiency, reducing greenhouse gas emissions, and minimizing nitrogen leaching during the cultivation of facility-grown eggplant. Full article

Straw returning is a common agricultural practice that can enhance rice (Oryza sativa L.) yield in paddy systems. However, it also leads to a significant increase in greenhouse gas emissions (GHG). Fortunately, this negative impact can be mitigated by implementing enhanced oxygenation strategies during rice cultivation. This study explored the effects of various oxygenation measures on GHG under straw-returning conditions through controlled pot experiments. Six distinct treatments were applied. These included straw not returned (NR, no straw applied), straw returned (SR), controlled irrigation (CI), oxygenation irrigation (OI), application of oxygenated fertilizer (OF, CaO₂), and use of biochar-based fertilizer (CF). All treatment groups, with the exception of the NR group, involved the return of straw to the field. Creating rice production methods that increase yield and decrease emissions is of great importance to agricultural ecology. We postulated that using aeration methods under straw return conditions would stabilize rice yield and reduce GHG. The experimental results were consistent with our hypothesis. The experiment evaluated multiple parameters, including rice yield, leaf photosynthetic performance, soil ammonium and nitrate nitrogen (N) levels, and greenhouse gas emissions. The findings revealed that different oxygenation approaches significantly promoted rice tillering. Oxygenation measures have been shown to enhance rice yield by 19% to 65%. The highest tiller numbers were observed in the SR (22.75) and CF (21.6) treatments. Among all treatments, the CF achieved the highest seed setting rate at 0.94, which was notably greater than that of the other treatments. Total plant biomass was also significantly higher in the straw returning treatment (109.36 g), surpassing all other treatments. In terms of soil nitrogen dynamics, the OF treatment resulted in the highest nitrate nitrogen content. Meanwhile, the ammonium nitrogen concentrations across the four oxygenation treatments (CI, OI, OF, CF) ranged from approximately 7 to 8.9 mg kg⁻¹. Regarding GHG, the CF treatment exhibited the lowest methane emissions, which were 33% lower compared to the straw returning treatment. The OF led to a 22% reduction in carbon dioxide emissions (CO₂) relative to straw returning. Most notably, the CF reduced nitrous oxide emissions by 37% compared to the straw returning treatment. Overall, SR was found to substantially increase GHG. In contrast, all tested oxygenation measures—CI, OI, OF, and CF—were effective in suppressing GHG to varying degrees. Among these, the CF and OF demonstrated the most balanced and outstanding effects, both in reducing emissions and maintaining stable rice yields. Full article