Search Results (485)

Cadmium (Cd) contamination in agricultural soils threatens food security and exacerbates climate change through its impact on greenhouse gas (GHG) (CO₂, N₂O and CH₄) emissions, in which N₂O and CO₂ are the dominant fluxes of the terrestrial carbon-nitrogen cycle whose magnitude is directly amplified by Cd stress. Key remediation approaches for this dual challenge are phytoremediation and biochar amendment. This study aims to investigate the effects of Solidago canadensis (CGR) and biochar (BC) on soil remediation and GHG emissions under different levels of Cd contamination. A pot experiment with four Cd concentration gradients (0, 5, 10, and 30 mg kg⁻¹, i.e., Cd-0, Cd-5, Cd-10, and Cd-30, respectively) and three remediation measures (control, BC addition, and CGR cultivation) was set up to measure available soil Cd (ACd), soil physicochemical properties, GHG emissions, and plant Cd accumulations. The results demonstrated that ACd was significantly reduced by BC via adsorption through surface complexation and by CGR via immobilization through root uptake and sequestration. CGR decreased ACd by 46.2% and 41.7% under mild and moderate Cd contamination, respectively, while BC reduced ACd by 8.9% under severe contamination. In terms of GHG emissions, CGR increased cumulative CO₂ by 83.4% in Cd-10 soil and 53.8% in Cd-30 soil, whereas BC significantly lowered N₂O emissions by 22.1% in Cd-5 soil. Mantel analysis revealed strong correlations between ACd and key carbon and nitrogen indicators, which mediate the bioavailability of Cd. Therefore, CGR cultivation is better suited to mild-to-moderate contamination given its high removal efficiency, while BC amendment is targeted at severe contamination by stabilizing Cd and mitigating N₂O. This provides a scientific basis for the remediation of Cd-contaminated soils. Full article

Ecological stoichiometry offers a powerful framework for linking the elemental composition of ecosystems to their biogeochemical functions. However, whether soil stoichiometry directly controls greenhouse gas (GHG) emission ratios remains largely unexplored. This study provides a case study investigating the link between the soil carbon-to-nitrogen (C:N) mass ratio and the gaseous C:N molar emission ratio in three distinct temperate island-like forests (Larix gmelinii forest, LGF; Betula platyphylla forest, BPF; and a Populus-Betula mixed forest, PBMF) in the Qixing River Wetland. Using the static chamber–gas chromatography method, we measured soil fluxes of CO₂, CH₄, and N₂O throughout the growing season. Our results revealed a strong, significant positive linear relationship (R² = 0.99, p < 0.001) between the soil C:N ratio and the gaseous C:N emission ratio across all forest types. The LGF, possessing the highest soil C:N ratio, exhibited the highest gaseous C:N emission ratio, driven by substantial CO₂ emissions (mean flux of 512.45 mg·m⁻²·h⁻¹). Furthermore, the Larix gmelinii forest (LGF) exhibited the highest total Global Warming Potential (GWP), primarily driven by its significant CO₂ emissions. In contrast, the PBMF was the strongest CH₄ sink (−25.82 μg·m⁻²·h⁻¹) and a N₂O emission hotspot (15.24 μg·m⁻²·h⁻¹), corresponding to its low soil C:N ratio. These findings provide strong evidence that soil elemental stoichiometry is a key driver regulating the functional signature of GHG emissions. This case study highlights the potential of using stoichiometric theory to develop predictive tools for assessing ecosystem sustainability and informing sustainable forest management strategies under climate change. Full article

This study evaluated the seasonal greenhouse gas (GHG) emissions and carbon assimilation of Bambusa edulis under four soil amendment treatments—control (C), biochar (B), fertilizer using vermicompost (F), and biochar plus fertilizer (B + F)—in a coastal shelterbelt system in south-western Taiwan. Over a 12-month period, CO₂ and N₂O fluxes and photosynthetic carbon uptake were measured. The control (C) treatment served as the baseline, exhibiting the lowest greenhouse gas (GHG) emissions and carbon assimilation. Its summer N₂O emissions were 39.54 ± 20.79 g CO₂ e m⁻², and its spring carbon assimilation was 13.2 ± 0.84 kg CO₂ clump⁻¹. In comparison, the amendment treatments significantly enhanced both emissions and carbon uptake. The fertilizer-only (F) treatment resulted in the highest levels, with peak summer N₂O emissions increasing by 306.5% (to 160.73 ± 96.22 g CO₂ e m⁻²) and spring carbon assimilation increasing by 40.2% (to 18.5 ± 0.62 kg CO₂ clump⁻¹). An increase in these values was also observed in the combined biochar and fertilizer (B + F) treatment, although the magnitude was less than that of the F treatment alone. In the B + F treatment, summer N₂O emissions increased by 130.3% (to 91.1 ± 62.51 g CO₂ e m⁻²), while spring carbon assimilation increased by 17.4% (to 15.5 ± 0.36 kg CO₂ clump⁻¹). Soil CO₂ flux was significantly correlated with atmosphere temperature (r = 0.63, p < 0.01) and rainfall (r = 0.45, p < 0.05), while N₂O flux had a strong positive correlation with rainfall (r = 0.71, p < 0.001). The findings highlight a trade-off between nutrient-driven productivity and GHG intensity and demonstrate that optimized organic and biochar applications can enhance photosynthetic carbon gain while mitigating emissions. The results support bamboo’s role in climate mitigation and carbon offset strategies within nature-based solution frameworks. 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

This study evaluates regional differences in ecosystem service values (ESVs) between the integrated rice–crayfish systems of Huoqiu County (HQ) and Chongming District (CM) in China. The assessment was based on the Common International Classification of Ecosystem Services (CICES) V5.1, which categorizes ecosystem services into provisioning, regulation and maintenance, and cultural services. In this framework, each service category was quantified using region-specific biophysical indicators combined with monetary valuation methods. The results showed that the ESVs in HQ and CM were 346,113.59 CNY/ha and 467,334.89 CNY/ha, respectively, with greenhouse gas (GHG) emissions accounted for as a negative value. Regulation and maintenance services dominated both regions (59% in HQ and 52% in CM), followed by provisioning services (22%) in HQ and cultural services (19%) in CM. Among these, temperature regulation, water storage and flood control, soil nutrient retention, social security functions, and greenhouse gas emissions were higher in HQ than in CM, with the key difference lying in social security value in HQ and greater tourism development value in CM. A SWOT-AHP analysis recommends a pioneering strategy leveraging strengths and opportunities for sustainable development. These findings inform region-specific policies to balance economic growth and environmental sustainability, contributing to global discourse on integrated agriculture–aquaculture (IAA) systems. Future research incorporating primary data and refining model parameters would further enhance the precision and practical application of these assessments. Full article

Climate change mitigation involves carbon sequestration that can be supported by Voluntary Carbon Markets (VCMs) and counted as Nationally Determined Contributions (NDCs) in national climate change strategies. Integrating these allows for the determination of greenhouse gas (GHG) emissions and carbon sequestration at the national level. The case for Egypt and other nontropical dryland nations is made in this systematic review article through consideration of monitoring, reporting, and verification (MRV) protocol challenges and initiatives. Improvements are indicated based on the literature, encompassing the academic literature as well as organizational reports and governmental policy documents. Agricultural MRV protocols depending on soil organic carbon (SOC) measurements are specifically considered, delineating the challenges and barriers for SOC MRV methods. Considering the impacts of climate zones affecting soils and providing as much standardization as possible for MRV protocols will improve the accuracy and generalizability of data. Measurements in carbon sequestration monitoring based on SOC MRV protocols need to be informed by soil experts alongside climatologists and policymakers in a multidisciplinary approach. Full article

With the escalating application of chemical fertilizers, the potential for environmental pollution has increased significantly. Currently, the degradation of soil quality due to the indiscriminate use of chemical fertilizers poses a more pressing challenge than ever before, threatening both human food production and the environment. The utilization of organic amendments not only enables the efficient recycling of organic waste resources but also reduces the reliance on chemical fertilizers. Meanwhile, organic amendments play a crucial role in soil improvement, helping to stabilize and enhance crop yields. Numerous studies have investigated the impacts of organic amendments on various aspects of crop production, including soil biology, biochemistry, heavy metal accumulation, and greenhouse gas (GHG) emissions. However, these studies have predominantly focused on isolated aspects rather than adopting a comprehensive perspective. Therefore, a comprehensive analysis of the positive and adverse effects of organic amendments is important in optimizing fertilizer use to meet crop nutrient demands and advancing carbon-neutral agriculture. This study mainly explores the intrinsic mechanism of the influence of organic amendments on soil physicochemical properties, enzyme activity and microbial diversity, heavy metal contamination and mobility, and GHG emissions in farmland. Finally, recommendations for the future development of organic amendments are proposed for promoting green and sustainable agricultural practices. Full article

Against the backdrop of global climate change, alterations in precipitation regimes—including the increasing frequency of extreme events—have become more widespread, exerting profound impacts on terrestrial ecosystems and reshaping greenhouse gas (GHG) emission dynamics in wetlands. Wetlands, as unique ecosystems formed at the interface of terrestrial and aquatic environments, play a critical role in regulating carbon source–sink functions. In this study, we conducted in situ field simulation experiments to examine how precipitation changes influence the seasonal fluxes of carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O) in the Wayan Mountain headwater wetlands, and further explored the regulatory effects of vegetation attributes and soil physicochemical properties on these fluxes. The results revealed that a moderate increase in precipitation (+25%) enhanced CO₂ emissions and vegetation growth while suppressing CH₄ and N₂O fluxes, indicating a positive ecosystem response to additional water supply. In contrast, extreme precipitation changes (+75% and −75%) weakened the coupling between GHG fluxes and soil factors, resulting in reduced CO₂ flux, amplified variability in CH₄ and N₂O emissions, and inhibited vegetation growth and community diversity. The dominant controls differed among gases: CO₂ was primarily regulated by soil carbon pools, CH₄ was highly sensitive to water availability, and N₂O was influenced by soil nitrogen, pH, and salinity. Overall, moderate increases in precipitation enhance the carbon sink capacity and community stability of alpine wetlands, whereas extreme hydrological fluctuations undermine ecosystem functioning. These findings provide important insights into carbon cycling processes and regulatory mechanisms of alpine wetlands under future climate change scenarios. Full article

Agricultural production in Zamora Chinchipe is primarily focused on dairy farming, an activity that constitutes a key component of land use in the region. Accordingly, the objectives of this study were as follows: (a) to estimate greenhouse gas (GHG) emissions from dairy farms using the GLEAM model and (b) to evaluate the influence of altitude and livestock management practices on soil properties and the estimated GHG emissions associated with cattle production. This study encompassed 100 dairy farms, where the GLEAM methodology was applied to quantify emissions-related data. In addition, 300 soil samples (three per farm) were collected, and the perimeter of each farm, as well as the remaining forest areas, was mapped. The results indicate that although the farms generate CO₂-equivalent emissions associated with livestock activities, the remaining forest areas contribute to mitigation by storing carbon in the soil. Altitude was found to positively influence soil quality, increasing organic matter and nitrogen content, whereas overgrazing negatively affected key soil properties and was associated with higher levels of GHG emissions. These findings underscore the need to implement sustainable management strategies that integrate agricultural production with the conservation of ecosystem services. Full article

The agricultural sector has a significant impact on the global carbon cycle, contributing substantially to greenhouse gas (GHG) emissions through various practices and processes. This review paper examines the significant role of the agricultural sector in the global carbon cycle, highlighting its substantial contribution to GHG emissions through diverse practices and processes. The study explores the trends and spatial distribution of agricultural GHG emissions at both the global level and within the European Union (EU). Emphasis is placed on the principal gases released by this sector—methane (CH₄), nitrous oxide (N₂O), and carbon dioxide (CO₂)—with detailed attention to their sources, levels, environmental impacts, and key strategies to mitigate and control their effects, based on the latest scientific data. The paper further investigates emissions originating from livestock production, along with mitigation approaches including feed additives, selective breeding, and improved manure management techniques. Soil-derived emissions, particularly N₂O and CO₂ resulting from fertilizer application and microbial activity, are thoroughly explored. Additionally, the influence of various agricultural practices such as tillage, crop rotation, and fertilization on emission levels is analyzed, supported by updated data from recent literature. Special focus is given to the underlying mechanisms that regulate these emissions and the effectiveness of management interventions in reducing their magnitude. The research also evaluates current European legislative measures aimed at lowering agricultural emissions and promoting climate-resilient, sustainable farming systems. Various mitigation strategies—ranging from optimized land and nutrient management to the application of nitrification inhibitors and soil amendments are assessed for both their practical feasibility and long-term impact. Full article

Soil degradation, declining fertility, and rising greenhouse gas emissions highlight the urgent need for sustainable soil management strategies. Among them, biochar has gained recognition as a multifunctional material capable of enhancing soil fertility, sequestering carbon, and valorizing biomass residues within circular economy frameworks. This review synthesizes evidence from 186 peer-reviewed studies to evaluate how feedstock diversity, pyrolysis temperature, and elemental composition shape the agronomic and environmental performance of biochar. Crop residues dominated the literature (17.6%), while wood, manures, sewage sludge, and industrial by-products provided more targeted functionalities. Pyrolysis temperature emerged as the primary performance driver: 300–400 °C biochars improved pH, cation exchange capacity (CEC), water retention, and crop yield, whereas 450–550 °C biochars favored stability, nutrient concentration, and long-term carbon sequestration. Elemental composition averaged 60.7 wt.% C, 2.1 wt.% N, and 27.5 wt.% O, underscoring trade-offs between nutrient supply and structural persistence. Greenhouse gas (GHG) outcomes were context-dependent, with consistent Nitrous Oxide (N₂O) reductions in loam and clay soils but variable CH₄ responses in paddy systems. An emerging trend, present in 10.6% of studies, is the integration of artificial intelligence (AI) to improve predictive accuracy, adsorption modeling, and life-cycle assessment. Collectively, the evidence confirms that biochar cannot be universally optimized but must be tailored to specific objectives, ranging from soil fertility enhancement to climate mitigation. Full article

Biochar has been widely recognized for its potential to improve soil quality and mitigate greenhouse gas (GHG) emissions. A field experiment was conducted in a temperate climate zone of Slovakia on Haplic Luvisol and evaluated the long-term impact of biochar on soil properties, nitrous oxide (N₂O) emissions, and winter wheat (Triticum aestivum L.) yield. Biochar was applied in 2014 at rates of 0, 10, and 20 t ha⁻¹ and reapplied in 2018 at the same rates, combined with nitrogen (N) fertilization (0, 140, and 210 kg N ha⁻¹). Measurements, conducted from March to October 2021, showed that biochar improved soil water content, increased soil pH, and enhanced soil organic carbon content. However, the concentrations of NH₄⁺-N and NO₃⁻-N generally decreased across all the treatments compared to their respective controls. Biochar reapplication rate at 20 t ha⁻¹, especially combined with second level of N-fertilization, led to a significant reduction in cumulative N₂O emissions by 38.40%. Winter wheat yield was positively correlated with both biochar application (10 and 20 t ha⁻¹) and N levels (140 and 210 kg N ha⁻¹), but these differences were not statistically significant (p > 0.05). The positive effects of biochar on soil properties and yield declined over time, with no significant yield differences observed 7 years after the initial application and 3 years after reapplication. These findings suggest that while biochar can enhance soil conditions and reduce GHG emissions in the short term, its long-term effectiveness remains uncertain. Further research is needed to explore alternative biochar feedstocks, application methods, and strategies to sustain its benefits in agricultural systems. Full article

Agriculture significantly contributes to greenhouse gas (GHG) emissions, yet fluxes from irrigated semi-arid systems remain poorly quantified. This study investigates CO₂, CH₄, N₂O, and NH₃ fluxes in a short-term lettuce experiment under semi-arid conditions. The objective was to quantify flux variability and identify key environmental and management drivers. High-frequency soil gas flux measurements were conducted under three treatments: irrigated soil (I), irrigated soil with plants (IP), and irrigated soil with plants plus NH₄NO₃ fertilizer (IPF). Environmental factors, including solar radiation, soil temperature, water-filled pore space, and relative projected leaf area, were monitored. A Random Forest model identified main flux determinants. Fluxes varied with plant function, growth, and fertilization. IP exhibited net CO₂ uptake through photosynthesis, whereas I and IPF showed net CO₂ emissions from soil respiration and fertilizer-induced disruption of plant function, respectively. CH₄ uptake occurred across treatments but decreased with plant presence. Fertilization in IPF triggered episodic N₂O (EF = 0.1%) and NH₃ emissions (EF = 0.97%) linked to nitrogen input. Vegetated semi-arid soils can act as CO₂ sinks when nitrogen is optimally managed. Excess or poorly timed nitrogen delays CO₂ uptake and increases reactive nitrogen losses. Methanotrophic activity drives CH₄ dynamics and is influenced by plants and fertilization. Maintaining crop vigor and applying precision nitrogen management are essential to optimize productivity while mitigating GHG and NH₃ emissions in semi-arid lettuce cultivation. Full article

Facility agriculture is essential for modernizing the production of horticultural plants, while long-standing over-fertilization and improper tillage in some vegetable facilities in northern China have resulted in reduced soil quality, increased greenhouse gas (GHG) emissions, and diminished vegetable yields and quality. This study systematically analyzed the deteriorating health of typical cucumber facility soils in Hebei Province, China, induced by long-term over-fertilization. Based on field surveys, we explored dynamic changes in soil physicochemical properties across different durations of over-fertilization. Subsequently, a series of field trials were conducted to assess whether reducing nitrogen application, either alone or when combined with microbial agents, could ameliorate soil properties, reduce greenhouse gas emissions, and enhance cucumber productivity. The initial field assessment revealed severe topsoil salt and nutrient accumulation, with water-soluble salt content in 5-year-old greenhouses from Yongqing soaring to 3.82 g·kg⁻¹, nearly eight times the level found in 1-year-old plots. Field experiments demonstrated that a 20% reduction in nitrogen application from the conventional rate of 900 kg·hm⁻² effectively mitigated salt accumulation, improved the structure of the microbial community, and maintained cucumber yield at 66,914 kg·hm⁻², an output comparable to conventional practices. More notably, integrating this 20% nitrogen reduction with an inoculation of Bacillus megaterium reduced the overall global warming potential by 26.7% and simultaneously increased cucumber yield to 72,747 kg·hm⁻². The most comprehensive strategy combined deep tillage, soybean straw incorporation, and B. megaterium application under reduced nitrogen, which boosted nitrogen use efficiency by 13.7% and achieved the highest yield among all treatments. In conclusion, our findings demonstrate that a combined approach of nitrogen reduction, microbial amendment, and straw application offers an effective strategy to restore soil health, enhance crop productivity, and mitigate environmental impacts in protective vegetable production systems. Full article

Global warming is expected to increase the frequency and intensity of extreme precipitation, yet its effects on soil greenhouse gas (GHG) emissions and functional stability remain uncertain. This study explored the impact of extreme soil moisture conditions on farmland and forest soil under three scenarios: 60% field water capacity (W1), soil saturation (W2), and 10 cm of standing water (W3). We used a laboratory incubation to evaluate how three extreme soil moisture regimes—60% of field water capacity (W1), soil saturation (W2), and 10 cm of standing water (W3)—affect GHG emissions and the functional stability of farmland and forest soils. Forest soils exhibited significantly higher global warming potential (GWP) than farmland across all regimes (p < 0.05). Relative to W1, farmland GWP increased by 0.14% under W3, whereas forest GWP increased by 13.7% under W2 (p < 0.05). Extreme soil moisture conditions markedly elevated total organic C (TOC) and ammonium N (NH₄⁺–N) contents in soil solutions from both farmland and forest, with increases of 25.0% and 6.0% for TOC and 78.6% and 69.6% for NH₄⁺–N, respectively. Conversely, nitrate N (NO₃⁻–N) content in farmland soil decreased by 3.54% and 6.96% under W2 and W3 treatments, while forest soil NO₃⁻–N increased by 39.68% under W2 and decreased by 39.13% under W3. Functional stability declined under extreme precipitation and was positively correlated with total CO₂ emissions, GWP, and TOC (p < 0.001), as well as with total N₂O emissions and soil total C (p < 0.05). Overall, forest soils maintained greater functional stability than farmland under extreme moisture. These findings clarify how extreme soil-moisture events influence soil functional stability in a warming climate and highlight the potential for post-event recovery of soil functions. Full article