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Biochar amendment offers a chance for sustainable agriculture. However, the effectiveness of biochar relies on its physical and chemical properties, which are heavily affected by biochar production conditions and management practices. Therefore, substantial uncertainties regarding the use of biochar exist in agricultural systems globally. This study provides the first quantitative evaluation of the impacts of biochar characteristics and management practices on key ecosystem services by performing a second-order meta-analysis based on 34,628 paired observations in biochar-amended and unamended systems. Overall, biochar enhances phytotoxicity alleviation, physiology regulation, soil remediation and carbon sequestration, and microbial functional gene abundance. However, some prominent trade-offs exist between crop productivity and ecosystem service deliveries including for nutrient cycling, microbial function, climate change mitigation, and the soil microbial community. The adoption of low C:N biochar produced at high pyrolysis temperatures from sewage sludge-derived feedstock, in combination with a moderate application rate and inorganic fertilizer input, shows potential for achieving synergistic promotion of crop productivity and ecosystem services. These outcomes highlight the need for judicious implementation of biochar-based solutions to site-specific soil constraints. The quantified synergy and tradeoff relationships will aid the establishment of a sustainable biochar development framework that strengthens necessary ecosystem services commensurate with food security assurance.

Debonding at the cement-casing interface is recognized as a principal failure mechanism leading to CO2 leakage in wells. This detachment gives rise to a microannulus, which notably possesses greater permeability than undamaged cement, undermining its sealing efficacy. Conventionally, the permeability of the microannulus is regarded as a uniform value throughout the well. However, fundamentally, a microannulus is one type of fracture, and its gap or aperture size is affected by the effective stress. In this work, we developed a unique experimental apparatus. This equipment facilitates the curing of cement inside a steel casing, the formation of a microannulus between the casing and the cement, and the investigation of the fluid flow dynamics along the microannulus under laboratory-replicated in situ conditions. The microannulus was formed by injecting fluid from one end of the setup, and receiving similar amount of fluid on the other end signified the development of the leakage channel. Additionally, strain gauges affixed to the casing’s external surface yielded key information on the microannulus’s opening and closure. We observed a noticeable decline in microannulus hydraulic aperture (or permeability) in relation to effective stress and an exponential equation fits their relationship. Our findings also indicate a distinct behavior when comparing liquid CO2 with water. Specifically, it is easier for liquid CO2 to create the microannulus. However, the hydraulic aperture range for this microannulus (0.7–6 μm) is considerably smaller than that created by water flow (2–17 μm). Finally, we integrated the stress-dependent microannulus aperture size into the combined analysis of well mechanical integrity and well leakage. The outcomes consistently demonstrated that when factoring in the stress-dependent aperture sizes, the leakage rates are 3–5 times compared to a fixed aperture model. The traditional assumption of a constant aperture significantly underestimates fluid leakage risks.

The embryonic technology of microbial electrosynthesis (MES) possesses the potential to alleviate global CO2 concentration with concomitant recovery of valuables. However, due to the significant bottlenecks of inferior yield of valuables and higher capital cost, its potential has not been fully realized at a larger scale till date. With the aim of bridging this lacuna, a first of its kind pilot-scale MES (PSMES) was designed and operated to yield acetic acid from biogas. The PSMES was able to produce 70.55 g m−2.day of acetic acid in its extraction chamber with the coulombic efficiency of 77.8 % for an imposed cathode potential of −1.0 V vs. standard hydrogen electrode. Moreover, life cycle assessment (LCA) and economic analysis of the PSMES was also conducted to elucidate the economic and environmental feasibility of the same. From the LCA and economic analysis of the PSMES, it was inferred that acrylic sheet and carbon felt used during the fabrication of PSMES were the major culprit in terms of both environmental and economic sustainability and thus should be replaced with greener but cost-effective materials. Therefore, these results would guide the budding scholars in designing more economical and environment friendly scaled-up MES, thus paving towards the commercialization of this ingenious technology.

Bamboo is an ideal plant for commercial production due to its rapid growth rate, high biomass production, low cost of production and environmental friendliness. Although Ethiopia has the highest bamboo cover in Africa, allometric equations for estimating its biomass are scarce. Most allometric models developed to date have been largely concerned with trees and shrubs. The objective of this study was to generate species- and site-specific allometric models that could be used to estimate the total aboveground dry biomass and culm dry biomass of lowland bamboo in northwest Ethiopia. Three power form-based allometric models were created using diameter at breast height (DBH) and culm height (H) as independent variables. One hundred and eight Oxytenathera abyssinica culms were used to predict the total aboveground biomass and culm biomass. Model one (M1) was the best model to predict the culm and total aboveground biomass of the species, regardless of forest type. The allometric models may provide useful information about aboveground biomass and culm biomass estimation methods to forestry professionals, bamboo producers and other stakeholders, and could help in the calculation of the country’s contribution to global carbon sequestration and trade.

With the intensification of the greenhouse effect, the climate-mitigation role of marine carbon sequestration (blue carbon) is gaining more attention. Seaweed aquaculture, as an important nature-based solution that provides various ecosystem services while as a food source, have become the main way of marine biological carbon sequestration. As an emerging carbon dioxide removal strategy, sinking seaweeds to the deep sea for additional CO2 sequestration to contribute to Paris Agreement temperature goal have attracted much attention. Currently, the ecological value assessment of sinking seaweeds is immature, and there is also a conflict between with traditional food values. However, in the long term, the value of carbon sequestration will continuously rise as global emission reduction advance, and rapidly growing seaweed production will be able to fully satisfy food demand in the future. Therefore, sinking surplus seaweeds to convert excess food value into higher ecological value is more compatible with development prospects, and long-term planning for sinking seaweed is particularly important. As the largest seaweed farming country, China accounted for more than half of the world’s production in 2021, possessing a huge potential for carbon sequestration. Incorporating factors such as food requirements, emission reduction demands and population changes, this paper explored the feasibility and planning of sinking seaweeds to serve the achievement of climate goals under five SSP-RCP scenarios in 2020–2050. The results indicate that with the slowdown in population growth and increasing demand for climate mitigation, the ecological value of seaweeds has more development potential than the edible value, and thus the sunken seaweed task should be placed more in the later period (2041–2050 phase) to maximize the ecological benefits of seaweed farming. Sinking seaweed is able to serve the SSP1-2.6 and SSP2-4.5 scenarios relatively well, while the realization of the SSP1-1.9 scenario presents some challenges.

The long-term establishment of artificial grasslands is considered one of the most rational management models for restoring the ''Black Soil Beach, BSB'' which promotes ecological succession characterized by increased biodiversity and improved soil health in the BSB. However, the relationship between grassland productivity recovery and soil stoichiometric balance during the long-term establishment process remains unclear. To elucidate this relationship, this study explored the impact mechanisms of soil nutrients, carbon and nitrogen sequestration, and soil stoichiometric features on grassland biomass across eight establishment periods (BSB, 1 year, 2 years, 5 years, 6 years, 10 years, 11 years, and 20 years). The results indicated that compared to the baseline BSB conditions, the aboveground biomass in artificial grasslands showed an increase ranging from 237.48 % to 815.1 %. The soil organic carbon stocks (SOCS) for 1-year-old artificial grassland (AG1), 2-year-old artificial grassland (AG2), 5-year-old artificial grassland (AG5), 6-year-old artificial grassland (AG6), 10-year-old artificial grassland (AG10), 11-year-old artificial grassland (AG11), and 20-year-old artificial grassland (AG20) increased by 79.7 %, 62.8 %, 60.6 %, 59.9 %, 87.5 %, 38.5 %, and 59.3 %, respectively, and the soil nitrogen stocks significantly increased during the early and middle stages of establishment. Moreover, as the establishment period prolonged, the 0–30 cm soil stoichiometric ratios (C:N, C:P, C:K, N:K, and P:K) significantly improved. Structural equation modeling revealed that soil stoichiometric ratios did not directly affect biomass, while the establishment period influenced plant uptake of total and available soil nutrients by altering soil physical properties, ultimately affecting biomass. This study unveils the mechanisms by which soil carbon and nitrogen sequestration, soil nutrients, soil stoichiometric ratios, and plant characteristics affect the productivity of long-term established artificial grasslands. These findings contribute to the development of management strategies for the sustainable restoration and conservation of alpine meadow ecosystems.

Rangelands are important for mitigating climate change and rehabilitating land by storing carbon from woody plants and seeds in the soil. However, there is a lack of empirical data on how traditional rangeland management practices (such as enclosure, communal grazing and prescribed fire) affect the carbon storage of woody species and the conservation potential of soil seed banks. This study evaluates the carbon sequestration and soil seed bank conservation potential of traditional rangeland management practices in the Western Guji zone, Ethiopia. A total of 32 sample plots were established using systematic random sampling, with 12 in each management practice, to measure woody biomass and estimate carbon stock using a nondestructive method. Additionally, 72 soil samples were collected for soil seed bank analysis, with 24 samples taken from each type of rangeland management practice. The study found that enclosures had the highest amount of carbon stocks 63.1 tons per hectare (t ha−1), with a corresponding carbon dioxide equivalent (CO2e) sequestration of 231.58 t ha-1, followed by communal grazing areas that stored 27.05 t ha−1 of carbon with a CO2e sequestration of 99.27 t ha−1. Prescribed fire had the lowest carbon stocks at 19.39 t ha−1, with a CO2e sequestration of 71.16 t ha−1. The study also found that different traditional rangeland management practices significantly influenced the diversity, richness, and density of woody species in soil seed banks. The highest Shannon diversity was recorded in enclosures (3.56 ± 0.09), followed by communal grazing (2.87 ± 0.14) and prescribed fire (1.27 ± 0.08). As a result, enclosure promotes the storage of carbon in woody plants and increases the diversity, density, and richness of woody species seeds in the soil, while prescribed fire reduces it. Therefore, it recommend for pastoralists to expand the use of enclosures as it improves the potential for conserving carbon stocks and soil seed banks of woody species.

The assessment of soil health and the determination of carbon stability in soils are current challenges that have gained momentum through initiatives at national as well as international scales. However, inferring universally valid soil health parameters that are directly linked to carbon permanence remains challenging. Our aim was to evaluate the potential of simultaneous thermal analysis (STA) for an improved monitoring of soil health advances in the context of carbon farming strategies. For this purpose, an on-farm comparison of soil health in ten conservation agricultural systems with adjacent conventional farms was performed based on STA and thermal measures were related to key biological and physical indicators for monitoring soil functions. Using an autocorrelation-based approach, we identified independent thermal indicators, revealing that carbon farming efforts predominantly increased labile soil organic matter fractions in the range of 300–400 °C, while thermally more recalcitrant fractions did not respond to farming system transformation. Similarly, most soil health indicators revealed highest correlation with temperature ranges of mass loss of labile organic matter fractions. The relation of STA with commonly used soil health indicators was highest for soil organic carbon (SOC, r=0.971) and total nitrogen (TN, r=0.981). However, also inference on microbial activity parameters such as dimethylsulfoxid reduction, microbial biomass carbon and substrate-induced respiration could be demonstrated with r>0.663. The results thus highlight key temperature ranges of organic matter stability for future soil monitoring tasks of climate change mitigation potentials of carbon farming and related advances in soil health.

Tropical forests play a significant role in climate change by sequestering atmospheric carbon dioxide. However, deforestation and forest degradation adversely affect these forests’ carbon stocks. Reports indicate that anthropogenic activities have led to forest degradation and deforestation in Boabeng Fiema Monkey Sanctuary (BFMS) and Kogyae Strict Nature Reserve (KSNR). This study assessed the effects of these activities on the carbon stocks of BFMS and KSNR. Using satellite imagery, field measurements and allometric models, carbon stocks of the study area were assessed from 1992 to 2023. The assessment revealed significant losses attributed to anthropogenic activities, such as hunting, farming and charcoal burning. BFMS experienced a total loss of 40,236 Mg C, while KSNR lost 272,109 Mg C. The closed forests had the highest carbon stock amongst the different vegetation types, with soil representing the most significant carbon pool in the protected areas, revealing the influence of vegetation structure on carbon sequestration and the need for soil conservation. The substantial carbon sequestration potential observed in the different vegetation types of the study area indicates that the Forest-Savannah Transition Zone is a prospective area for climate change mitigation aligning with the Sustainable Development Goals (Goals 13 and 15) and the National Climate Change Policy of Ghana. These findings provide valuable insights for carbon trading and biodiversity conservation, emphasizing the potential of nature-based solutions in addressing global climate challenges.

Accurately accounting for soil organic carbon stocks is crucial in assessing the sequestration potential of arid and semi-arid rangelands. This study, conducted in the rangelands near Loving, southeastern New Mexico, aims to evaluate soil organic carbon stocks, assess the potential for soil organic carbon sequestration, and identify both biotic and abiotic factors influencing this process. To achieve these goals, soil samples were collected and subjected to analysis for soil particle size, bulk density, soil characteristic curve, as well as soil total carbon and inorganic carbon. Soil total carbon stock (STCS), soil organic carbon stock (SOCS), soil inorganic carbon stock (SICS), and soil total nitrogen stock (STNS) were determined. Soil depth, vegetation types, and coverages on each ranch were identified. Additionally, soil ion concentrations, soil cation exchange capacity (CEC), and soil sodium adsorption ratio (SAR) were assessed. The soil CEC ranged from 6 to 20 meq/100 g soil, and SAR from 0.02 to 0.58 cmol/kg^0.5. The concentrations of Na and Cl were 42 and 13 mg/l, at a depth of 0–20 cm, increasing to 74 and 34 mg/l at 20–32 cm depth, respectively. In October 2021, STCS measured 39 Mg/ha at 0–20 cm and 11 Mg/ha at 20–32 cm soil depth. SOCS ranged from 18 Mg/ha at 0–20 cm to 6 Mg/ha at 20–32 cm soil depth, while SICS ranged from 20 to 1 Mg/ha at 0–20 cm and 20–32 cm soil depth, respectively. STNS varied from 1 Mg/ha at 0–20 cm to 3.8 Mg/ha at 20–32 cm soil depth. In the 20 cm sandy loam soil depth, ranches 1, 7, 8, 9, and 11 exhibited the highest SOCS, increased with increasing clay content, particularly where honey mesquite was the dominant species. These findings emphasize the importance of exploring soil carbon storage fluctuations in southern New Mexico. The differences in SOCS among ranches under different vegetation underscore the considerable potential for storing soil organic carbon in the semi-arid rangelands of this region.

Forest thinning is an effective measure to improve carbon sequestration (CS) to adapt to and mitigate global warming. However, reducing forest cover could negatively affect other ecosystem services such as soil conservation (SC), making it difficult to effectively implement thinning strategies. This problem is exacerbated by a lack of previous research. Accordingly, after assessing thinning for two typical trees (Robinia pseudoacacia L. (RP) and Quercus L. (QL)) in Shaanxi Province, we propose a forest management framework that provides detailed thinning strategies and improves CS using a process-based biogeochemical model (Biome-BGCMuSo) by considering future climate change and SC constraints. After calibration for Biome-BGCMuSo, the average root mean squared error and percentage bias for the simulated results and observed data of RP and QL decreased (39.2–54.5 % and 66.0–86.9 %) and the correlation coefficient and Nash–Sutcliffe efficiency improved (11.6–12.3 % and 114.7–153.0 %,) respectively. Comparison between current (2001–2020) and future (2081–2100) conditions predicted overall future CS increase, and future SC would display either increasing or decreasing trends in different climatic scenarios and subregions. Partial correlation analysis showed precipitation as the dominant factor positively influencing SC, while temperature, precipitation, and CO2 concentration were the dominant factors positively influencing CS. Based on the proposed framework, RP and QL should be thinned three times every 7–11 and 3–11 years during the non-growing season with intensity ranges of 2–27 % and 1–9 %, respectively. Although the average CS during 2023–2100 with thinning increased slightly (0.1–2.6 %) compared with that without thinning, a notable potential to increase CS (0.2–7.7 %) was observed for thinning during a period at the end of this century predicted to experience the most warming. The proposed framework facilitates maximizing CS and maintaining SC. As the framework is based on a process-based biogeochemical model, it could be applicable to other regions.

Deforestation is a key factor in global climate change, severely impacting ecosystem services. Effective implementation of reducing emissions from deforestation and forest degradation (REDD+) initiatives is essential for mitigating this change. Reforestation is a sustainable way to mitigate deforestation effects. We studied the impact of assisted natural regeneration (ANR) on restoring dry forest land, increasing biodiversity, structure, and carbon stock. Reforestation units were established at a multiple row planting system in a dry tropic region. We selected 63 plots, each 20 m × 20 m, categorized into multiple row–mixed plantation (MRMP) and multiple row–unmixed plantation (MRUP). We measured tree height and diameter at breast height (DBH) and evaluated biodiversity indices, including the Shannon–Weiner Index (SWI), species richness, evenness, and Important Value Index (IVI). Carbon stock was estimated using allometric equations. We identified 931 individual trees representing 27 species, 24 genera, and 14 families. MRMP showed significantly higher biodiversity, species richness, and evenness than MRUP. Terminalia arjuna was the most dominant species (IVI=124.45), followed by Khaya senegalensis (53.84). Survival rates exceeded 90 % for T. arjuna, K. senegalensis, Madhuca longifolia, and Pongamia pinnata (p

Biochar, as a carbon-rich substance produced from the thermal decomposition of organic biomass, is promising for sustainable environmental management. The production and consumption of this substance can directly and indirectly lead to the reduction of carbon emissions and, as a result, in neutralizing the effects of global warming and climate change can actively participate. The biochar route can be even more powerful than the bioenergy route in terms of carbon reduction targets. In line with these facts, this review tries to study biochar, its production by slow thermal decomposition biochar, and its diverse applications to reduce climate change and ecosystem stability. Also, the applications of biochar such as carbon sequestration, soil strengthening, and reducing pollutants are technically and environmentally discussed. Biochar's adaptability is consistent with sustainable development goals, making it a valuable tool for tackling global challenges such as climate change, soil degradation, and pollution control. Through the process of pyrolyzing residues and producing biochar, it is possible to avoid cumulative emissions of 66–130 billion metric tons of CO2 equivalent over a century. Approximately 50 % of these avoided emissions result from the long-term carbon sequestration capabilities of biochar. Additionally, 30 % of the reductions come from substituting fossil fuels with pyrolysis-derived energy, while the remaining 20 % arise from the prevention of methane and nitrous oxide emissions. Reflecting its growing significance, the biochar industry, valued at approximately USD 541.8 million in 2023, is poised for remarkable growth. Projected to expand at an impressive annual rate of 13.9 % from 2024 to 2030.

In recent years, a discernible surge in greenhouse gas emissions has precipitated severe global warming, with the construction industry identified as a notable contributor, particularly through carbon dioxide emissions from cement production. As concrete stands as the second most extensively utilized material globally, its pervasive use amplifies the release of potent greenhouse gases. This paper introduces a novel approach to carbon capture in concrete materials by employing CO2 adsorbents that synergistically enhance the carbonization reaction, thereby augmenting capture efficiency. Biochar emerges as a promising candidate for carbon capture due to its robust CO2 adsorption capacity and its eco-friendly, cost-effective, and low-carbon production process. For instance, typically 1 ton of biochar has potential to sequester 3 ton of carbon dioxide from the environment. Various studies have explored the integration of biochar into concrete materials, aiming to improve mechanical, durability, and thermal properties, as well as the overall functionality of formed concrete composites. Beyond its role in enhancing concrete properties, biochar presents itself as an effective carbon sequestering agent with or without modification which is also reviewed in this paper. Concurrently, research efforts are underway to investigate the reinforcement properties and selective CO2 sorption capabilities of cellulose-based materials in concrete composites. Noteworthy attributes such as abundance, biodegradability, renewability, and cost-effectiveness position cellulose-based materials as promising alternatives to traditional reinforcing agents. This paper provides a comprehensive review of the latest advancements in the utilization of biochar and cellulose materials in concrete composite applications. Emphasis is placed on evaluating the durability, mechanical properties, and carbon capture potential of concrete composites augmented with biochar and cellulose. The synthesis of research progress in this domain serves to elucidate the current state of knowledge and offers insights into the future prospects of biochar and cellulose-enhanced concrete composites in the context of sustainable construction practices.

The growth of eggplant (Pusa Safed Baingan-1) was studied during the semi-arid (March to June) and humid sub-tropical (July to September) seasons of New Delhi, India. The individual effects of wheat straw biomass (WSBM), wheat straw biochar (WSBC) and compost versus the combined effect of WSBM plus compost and WSBC plus compost were determined under field conditions. The amendments were made at two different application rates: 1 wt% and 2 wt%. WSBC was successfully prepared in a proprietary kachcha reactor (Indian patent no. 380921), designed using locally sourced clay. Amendments were characterized using elemental analyzer, scanning electron microscopy (SEM), transmission electron (TEM) microscopy, Fourier transform infrared (FTIR) spectroscopy and X-Ray diffraction (XRD). The field study was conducted in 11 (1x1-meter) plots with two replicates. Basic soil health parameters including pH, electrical conductivity (EC), water holding capacity (WHC), bulk density (BD), cation exchange capacity (CEC), soil total nitrogen (STN), soil available nitrogen (SAN), soil organic carbon (SOC), soil available phosphorus (SAP), microbial biomass carbon (MBC) and mineral contents are analyzed. Observable plant growth characteristics (germination percentage, height, number of leaves, fruits, and plant biomass) were also recorded. Biochar amendment was most beneficial for enhancing the majority of these parameters. With respect to the control, a 20% decrease in bulk density, a 30% increase in water holding capacity, a 122% increase in organic carbon, a 175% increase in total nitrogen, a 23% increase in available nitrogen, and a 473% increase in available phosphorus were recorded. Furthermore, with respect to the control, a 115% increase in CEC was recorded using the compost amendment vs 84% with WSBC. Synergism between biochar and compost was reflected by high germination percentage (44%), number of fruits (600%), plant biomass weight (243%) and soil microbial biomass carbon (286%). Biomass amendment failed to show any positive influence. In summary, biochar emerges as a superior choice compared to both biomass and compost when it comes to soil amendments.

Soil, the largest terrestrial carbon reservoir, is central to climate change and relevant feedback to environmental health. Minerals are the essential components that contribute to over 60% of soil carbon storage. However, how the interactions between minerals and organic carbon shape the carbon transformation and stability remains poorly understood. Herein, we critically review the primary interactions between organic carbon and soil minerals and the relevant mechanisms, including sorption, redox reaction, co-precipitation, dissolution, polymerization, and catalytic reaction. These interactions, highly complex with the combination of multiple processes, greatly affect the stability of organic carbon through the following processes: (1) formation or deconstruction of the mineral–organic carbon association; (2) oxidative transformation of the organic carbon with minerals; (3) catalytic polymerization of organic carbon with minerals; and (4) varying association stability of organic carbon according to the mineral transformation. Several pieces of evidence related to the carbon turnover and stability during the interaction with soil minerals in the real eco-environment are then demonstrated. We also highlight the current research gaps and outline research priorities, which may map future directions for a deeper mechanisms-based understanding of the soil carbon storage capacity considering its interactions with minerals.

The long-term persistence of biochar in soil is often predicted by extrapolating mineralization data from short-term laboratory incubations. Single first-order, double first-order, triple first-order and power models have been employed for this purpose, all of which have an inherent assumption that biochar is biodegradable. However, recent insights challenge this assumption by suggesting that a large fraction of biochar is inert. If so, it would make sense to reflect this in the models used, by incorporating an inert carbon (C) pool. We hypothesized that such inert pool models would fit better to incubation data than existing models and give more reliable long-term predictions. We evaluated this by fitting the models to data from a recently compiled extensive dataset of biochar incubations. The inclusion of an inert pool enhanced the model fits over first-order models in most cases. However, inert pool models overestimated biochar persistence compared to the measured outcomes. By contrast, the double first-order model, which has been the most widely used to date, underestimated biochar persistence even in the short term. The power model in general outperformed all other models and gave the most reliable predictions, although it was sensitive to increasing or fluctuating mineralization rates in the datasets.

Urban flooding has been considered one of the most severe natural disasters around the world, and urban greenspaces can provide important flood regulation ecosystem services. In Belo Horizonte (Brazil), the woody vegetation, especially the old-growth Ficus trees, appears to protect an urban park against the flooding of the Arrudas river. Thus, we compared the soil water content, soil water-holding capacity, soil aggregation and porosity among a highly permeable urban park planted with herbaceous and woody species, including Ficus, a semi-permeable parking lot with only Ficus and an impermeable site without trees (Disturbed Site-DS). The soil water content and water holding capacity of the urban park did not differ from that of the Ficus site, but it was lower than DS. These results were correlated with soil organic matter (SOM) content, soil aggregation and porosity, suggesting that Ficus trees play an important role in the hydrological cycle. To understand how the Fiscus species provide such soil permeability, we compared the aboveground plant biomass, soil fertility and soil carbon sequestration (total soil carbon, soil organic matter, humic and fulvic acids and soil isotopic δ13 C) in plots with Ficus and without this species within the park as well as in a preserved urban forest and a disturbed square. The outstanding plant biomass produced by Ficus species explained the high soil carbon sequestration, particularly in humic organic matter, favouring soil aggregation, porosity and water retention. Therefore, Ficus species may be considered an exceptional C-sequestering species, contributing for soil stabilization and the hydrological cycle in urban greenspaces.

Tree plantations substantially sequester carbon in aboveground biomass and soil and serve as an alternative to forests in mitigating global warming. This study investigated the relationship between aboveground carbon and stand characteristics and management activities in two Japanese plantations (cedar and cypress) for their sustainable management viewpoint, which has not been studied before. Aboveground carbon stock ranged from 3.96 to 248.53 Mg C ha-1 in 9- to 188-year-old Japanese cedar and 7.09 to 119.17 Mg C ha-1 in 11- to 129-year-old Japanese cypress plantations. Annual aboveground carbon storage differed significantly between the two species. Aboveground carbon storage in Japanese cedar was affected by stand characteristics (e.g. soil moisture, electrical conductivity, soil texture especially sand and clay, site quality, and stem density) and management activities (e.g. initial silvicultural practices, stem exclusion practices, pest and wildlife management and land management). However, the same in Japanese cypress was affected by stand characteristics (e.g. soil moisture, electrical conductivity, soil texture especially sand, bulk density, site quality, stem density, and elevation) along with management activities (e.g. initial silvicultural practices, stem exclusion practices and land management). Therefore, continuous monitoring and periodic assessment of the stand characteristics and management activities may be taken into consideration in future policy-making decisions to promote aboveground carbon storage and climate change mitigation ability of these plantations in Japan on a sustained basis.

To ensure sufficient reaction between concrete and carbon dioxide, carbon dioxide was added during the concrete mixing process. The study involved varying water-to-cement ratios (W/C), carbon dioxide pressure, and carbon dioxide concentration to create different cement mortar samples. The research aimed to observe the effects of carbon dioxide sequestration under these parameters. Subsequently, mortar concrete properties were tested at different curing times. The findings indicated that this method enhanced the efficiency of cement mortar in absorbing carbon dioxide. The results revealed that mixing mortar with carbon dioxide led to a rapid reaction, reducing the initial setting time of cement mortar. However, it was observed that this method significantly decreased the workability of cement mortar after carbon dioxide mixing, and this effect could potentially be mitigated by adjusting the W/C or using a superplasticizer. The bond of cement was also found to decrease after reacting with carbon dioxide, consequently impairing the compressive strength of the concrete. Nevertheless, the compressive strength remained within acceptable limits. It is essential to note that the carbonation of the concrete and its ability to protect reinforcement from rusting were compromised due to the reduced pH value of the concrete. Further assessment of the durability is necessary, particularly if this method is applied to reinforced concrete structures.

Woody aboveground biomass (AGB) including short-rotation Populus is used as a feedstock for renewable and carbon-neutral bioenergy. While woody AGB can be estimated with allometric equations requiring labor-intensive field data, remote sensing technologies like mobile terrestrial light detection and ranging (LiDAR) can estimate woody AGB quickly and accurately. Therefore, the goals of this study were to develop a model to predict woody AGB of 2-year-old Populus spp. from three taxa (P. deltoides, P. deltoides × P. maximowiczii and P. deltoides × P. trichocarpa) using allometric (height and diameter at breast height (DBH)) or LiDAR-derived metrics from a mobile terrestrial (backpack) system. Likewise, we sought to compare LiDAR-estimated tree height and DBH with field-measured values. We found that a taxa-specific model containing LiDAR-measured tree height, crown volume, and taxa interactions with the height of the 10th percentile, and the density of the lowest interval (density metric 0) explained 84 % of the variation in woody AGB with a root mean square error (RMSE) of 28.7 % and performed slightly better than the allometric model. The best model excluding taxa had a slightly higher RMSE but lower bias than the allometric model. LiDAR-derived tree heights were highly correlated with field-measured heights, but DBH could not be estimated accurately. Therefore, terrestrial mobile LiDAR systems can accurately estimate woody AGB and tree height of Populus in short rotation systems to aid in the fast and efficient quantification of woody bioenergy production and renewable energy resources.

Carbon mineralization is an emerging field of research in carbon sequestration. In this process, dissolved inorganic carbon reacts with mineral cations such as Ca2+ and Mg2+ to form stable carbonate minerals, enabling permanent carbon sequestration and storage. However, current mineralization methods predominantly rely on physicochemical approaches to expedite the mineralization of carbon. While effective, these methods require substantial chemical and energy consumption and may cause significant environmental impacts. Biomineralization has recently emerged as a sustainable alternative, leveraging biochemical reactions to catalyze CO2 mineralization. This research focuses on investigating the specific roles of various biomolecules in natural carbon biomineralization and exploring state-of-the-art biomimetic carbon mineralization techniques, including whole-cell microbially induced carbonate precipitation (MICP) and cell-free systems, for carbon sequestration. In addition, we discuss various sources of mineral cations, ranging from natural minerals to industrial waste to seawater, along with their advantages and limitations. Our findings highlight the potential and feasibility of biological carbon mineralization processes to contribute towards sustainable carbon sequestration. However, we also identify challenges and propose future directions to guide further research and the application of these processes.

Urban forests are considered a nature-based solution for climate change by cities and countries worldwide. However, the effectiveness of large-scale urban forest projects as a natural climate solution has been rarely assessed. In this study, we utilized a unique opportunity from Beijing's actions to implement a large urban forest project since 2012 to examine the effectiveness of the proposed solution. We collected vegetation structure data in two extensive field surveys to track the growth of the newly formed urban forest. Using field data and allometric equations, we estimated carbon sequestrated by the urban forest. We found that between 2013 and 2020, the urban forest grew rapidly, with the average increase of DBH and height reaching 0.95 cm and 0.47 m annually, respectively. The 16,667 ha of trees and shrubs sequestrated 423,074 tons of carbon in ten years, or 42,307 tons annually. The result showed that large-scale urban forest projects have the potential to be used as a natural climate solution (NCS). Nevertheless, planning and developing specific management techniques are needed to fully realize this potential.

Soil organic carbon (SOC) is crucial for soil health and quality, and its sequestration has been suggested as a natural solution to climate change. Accurate and cost-efficient determination of SOC and its functional fractions is essential for effective SOC management. Visible near-infrared spectroscopy (vis-NIR) has emerged as a cost-efficient approach. However, its ability to predict whole-profile SOC content and its fractions has rarely been assessed. Here, we measured SOC and its two functional fractions, particulate (POC) and mineral-associated organic carbon (MAOC), down to a depth of 200 ​cm in seven sequential layers across 183 dryland cropping fields in northwest, southwest, and south China. Then, vis-NIR spectra of the soil samples were collected to train a machine learning model (partial least squares regression) to predict SOC, POC, MAOC, and the ratio of MAOC to SOC (MAOC/SOC – an index of carbon vulnerability). We found that the accuracy of the model indicated by the determination coefficient of validation (Rval2) is 0.39, 0.30, 0.49, and 0.48 for SOC, POC, MAOC, and MAOC/SOC, respectively. Incorporating mean annual temperature improved model performance, and Rval2 was increased to 0.64, 0.31, 0.63, and 0.51 for the four carbon variables, respectively. Further incorporating SOC into the model increased Rval2 to 0.82, 0.64, and 0.59, respectively. These results suggest that combining vis-NIR spectroscopy with readily-available climate data and total SOC measurements enables fast and accurate estimation of whole-profile POC and MAOC across diverse environmental conditions, facilitating reliable prediction of whole-profile SOC dynamics over large spatial extents.

This study performs a comparative analysis of tree composition, biomass, and carbon stock across different management regimes namely, Van Panchayat forest (VP), Reserve forest (RF), and Civil & Soyam forest (C&SF) in the state of Uttarakhand, with a focus on P. roxburghii (Chir-pine) forests. Collectively, these management regimes cover approximately 60 % of the forest area in the state. In this assessment, a total five tree species (Pinus roxburghii, Quercus leucotrichophora, Myrica esculenta, Acacia catechu, and Pinus wallichiana) were identified across the management regimes. The Pinus roxburghii emerged as the dominant species across all management regimes, with relative density of 92.79, 94.39, and 92.31 % in Van Panchayat forest, Reserve forest, and Civil & Soyam forest respectively. However, co-dominant species are varying across the sites. The total tree biomass and carbon stock were notably higher in Van Panchayat forest (236.31 & 112.25 t ha−1) compared to Reserve forest (224.85 & 106.80 t ha−1) and Civil & Soyam forest (193.58 & 91.95 t ha−1). These findings suggest that Van Panchayat forests exhibit a superior status in terms of density, biomass, and carbon stock as compared to Reserve and Civil & Soyam forests. Pinus roxburghii emerges as a crucial species, underscoring its ecological significance in the region. These findings underscore the critical role of effective forest management practices in fostering sustainable biomass accumulation and carbon sequestration in the Himalayan Chir-pine forests. Thus, it helps to mitigate the impacts of climate change and biodiversity conservation, and sustainable management of forests.

Biodegradable film (BF), as a superior substitute for traditional polyethylene film (PF), has experienced a consistent increase in China. However, a significant research gap persists regarding the utilization of BF in assessing farmland carbon balance. This experiment examined the responses of maize growth, yield, irrigation water productivity (IWP), CO2 emissions, and field net carbon sequestration (NCS) to two BF types (BF1, 100-day induction period, and BF2, 80-day induction period), and PF, and three irrigation amounts (I1, I2, I3: 5250, 5625, and 6000 m3 ha–1), by conducting a two-year (2019–2020) field trial in a typical arid and semi-arid region of China. The results indicated that biodegradable film mulching (BFM) negatively affected maize growth, resulting in reduced yield and IWP. Especially under the I1 irrigation level, the biodegradable film reduced maize yield by 6.26%–13.99% and IWP by 6.64–13.85%. Notably, in the I2 irrigation level, BF1 mulching had a comparable impact on maize yield and IWP to that of PF. Additionally, the increase in irrigation amounts exerted a more pronounced promoting effect on maize total biomass than on yield and IWP. Concerning carbon balance, short-term BF application resulted in reduced CO2 emissions (5.74–6.30% under BF1 and 9.27–12.37% under BF2), without any significant impact on NCS in cropland. Taking into account the economic value of maize and farmland ecology, we recommended utilizing irrigation amounts of 5625 m3 ha–1 for BF application in arid areas, while opting for a BF with a longer induction period whenever feasible.

CO2-mixing by directly injecting CO2 into fresh cement-based materials is a burgeoning technology to produce low-carbon cement products. The objective of this study is to investigate the influence of the calcium carbide slag (CCS) content on the properties and carbon sequestration efficiency of cement pastes mixed under direct CO2 injection conditions. The results indicate that the addition of CCS reduced the fluidity of the cement pastes, accelerated the setting process, increased volume shrinkage, and reduced compressive strength. Following the injection of CO2 into the cement pastes, calcium hydroxide (CH) was carbonated to form calcium carbonate (CC) particles which fill the voids in the cement pastes, thereby reducing volume shrinkage and increasing compressive strength. A lower CO2 inflow rate (2 L/min) was more beneficial to the workability of the cement pastes, while a high inflow rate (6 L/min) can lead to insufficient hydration and affect the development of strength. However, a higher CO2 inflow rate was favorable for improving carbon sequestration efficiency. The highest amountof carbon sequestration can be reached at 6.93 %, when the CCS content is 10 % and the CO2 inflow rate is 6 L/min.

Microalgae has great potential in carbon sequestration and production of biofuel even with a low concentrations of CO2. In this paper, an Andrews based microalgae growth kinetic model and a novel and multiple nutrient supplementary scheme that significantly extends the carbon sequestration period and enhances growth rates of microalgae are proposed. First, the correlation between nutrient concentration and microalgal growth is constructed experimentally. The advanced growth kinetic model incorporating nitrogen and phosphorus consumption is developed. Then, the optimum cultivation conditions including initial nutrients concentration, nutrients supplementary interval and daily nutrients supplementary quantities are obtained in the conical flask reactor. The findings led to a novel nutrient supplementation strategy that initiates with a 0.2BC concentration, followed by a 0.3BC addition at 100 h, with subsequent supplements every 72 h. After adopting this supplementary strategy, the microalgae growth rate is increased by 42.9 % and the carbon sequestration rate is increased by 56.2 % compared with that of the original microalgae cultivation method in one cultivation cycle. Finally, the universal microalgae nutrients supplementary model is proposed in a piecewise model. It can be concluded from the model that in the first cultivation period, microalgae needs a higher affinity for nutrients and after nutrients supplementary, the sensitivity to nutrient inhibition is reduced. The paper is significantly helpful to improve the sustainability of the microalgae growth rate and the carbon sequestration rate.

Community Forestry (CF) is recognized globally as a forest management regime with the potential to address deforestation and forest degradation, provide forest goods and services to local communities and contribute to climate change mitigation. Around 4% of Bhutan's forests are currently under CF management and these forests provide essential goods and services for local communities. However, the potential of CF in Bhutan to contribute to climate change mitigation is not well understood and has not been researched.In this study, we estimated the carbon stock and carbon sequestration of community forests in Bhutan by using data from the 2015 National Forest Inventory (NFI). The total biomass carbon in community forests was 130.3 Mg ha−1 (107.3–153.2) and the soil organic carbon was 52.8 Mg ha−1 (30.4–75.1). Carbon sequestration was 0.7 Mg ha−1 yr⁻¹. Other attributes: basal area, stem density and tree height, were also determined to assess forest condition and the potential to increase carbon sequestration.The values for biomass carbon in Bhutan's community forests as well as the non-community forests (all other forests) were similar to those reported from Forest Resource Assessment and NFI for forests in Nepal and the Indian Himalayan states respectively. Disaggregation of data from 38 research studies across the Himalayan region indicated that biomass carbon in Bhutan's forests was significantly lower than that in well-stocked (non-degraded) forests in the Indian and Nepal Himalayas. It was also much lower than that in Bhutan's Forest Management Units, which were used as an indicator of the potential upper limit of biomass carbon in Bhutan's forest environment. Similarly, basal area, stem density and mean tree height were also lower in Bhutan's community forests than in well-stocked forests in other Himalayan countries.The Bhutan Government is currently exploring the potential to generate revenue from the sale of carbon sequestered in its forests. This study confirms that there is potential to increase carbon sequestration by improving management of existing forests. Currently, the 107,866 ha of community forests in Bhutan store about 19 million Mg of carbon. With improved management by Community Forest Management Groups, which have the institutional capacity to control local management outcomes, the carbon stock could likely be doubled (to 40 million Mg of carbon), thereby demonstrating the potential of Community Forestry to play an important role in climate change mitigation, while not jeopardizing the provision of day-to-day goods and services to local communities.

In the 21st century, tackling climate change is an important challenge, and the absorption of CO2 via urban greening employing photosynthesis offers a potential answer to the climate issue. Within this work, the city of Nador is chosen as a case study. The initiative in question proposes an enhanced technique focused on estimating the advantages of urban greening in terms of carbon storage and sequestration. This technique combines the use of Geographic Information Systems (GIS) tools and the InVEST model, enabling the study of land use and land cover (LULC) scenarios within the location. These scenarios contain numerous alternatives, ranging from the adoption of intense and extensive green roofs to the establishment of gardens and woodland areas. The carbon storage modeling technique depends on the exploitation of land use maps, reinforced by a bibliographic examination of the key carbon reservoirs. The analysis of results from biophysical modeling indicates a considerable increase of over 45.36 % compared to the existing condition when the option of extensive green roofs is chosen. In the setting of extensive green roofs, this rise reaches a rate of 64.20 %. Furthermore, the restoration of the Gourougou forest north of the city leads to an increase of 70.30 %. The adoption of diverse combinations, such as the integration of green roofs with urban vegetation, greatly helps to further enhancing carbon storage. From a financial perspective, the additional value can range from $2,012,825.16 to $3,601,025.53, depending on the chosen scenario. This financial assessment highlights the possible advantages that might be converted into carbon credits in return for emission reduction, partially offsetting the expenses associated with the adoption of each greening solution. Ultimately, these findings give a chance for urban planners and green architecture professionals to perform in-depth planning analyses.

Straw return is a vital soil amendment practice in Chinese upland soils, aiming to improve the soil organic carbon (SOC) stock. However, its impact on SOC stock depends on various fertilizer practices, leading to inconclusive results. To address this, we conducted a meta-analysis of 121 peer-reviewed publications to evaluate the effect of straw return combined with different fertilization practices including balanced NPK (BFS), unbalanced NP, NK, PK, or N fertilization (UFS), and no fertilization (NFS) in the wheat-maize cropping system. The results showed that straw return with BFS led to the highest increase in SOC stock (13.3%), followed by UFS (11.4%) and NFS (6.12%), compared to straw removal under the same fertilization conditions. BFS also significantly increased the soil C (15.9%), N (9.62%), and P (6.21%) contents, as well as the C:N (2.48%) and C:P (11.4%) ratios. In contrast, UFS resulted in higher C:N ratios (6.47%) and soil acidification, affecting the SOC stock during straw return. A structural equation model revealed that the presence of BFS positively influenced the association between SOC stock and soil stoichiometry (P ​12 ​g ​kg−1). Based on C sequestration efficiency, implementing straw return with BFS could lead to a higher rate of increase in SOC sequestration.

Humification plays a significant role in converting phenolic pollutants and forming heterogeneous polymers, but few studies have been performed to investigate exolaccase-started humification (ESH). Herein, the influences of lignin precursors (LPs) on exolaccase-induced bisphenol A (BPA) removal and humification were explored. In particular, the architectural features and botanical effects of the formed humification products were also tested. ESH was extremely beneficial in boosting BPA removal in the presence of LPs. Compared with LP-free (58.49%), 100% of BPA was eliminated after the reaction with ESH for 72 h. Such a process was controlled by an exolaccase-caused random assembly of radicals, which generated a large number of hydrophobic polymers through nonspecific covalent binding of C–C and/or C–O. These humified polymers were extremely stable at pH 2.0–10.0 and −20 °C to 80 °C and displayed unique functions, i.e., scavenged 2,2-diphenyl-1-picrylhydrazyl/2,2′-azino-bis3-ethylbenzothiazoline-6-sulphonic acid radicals and exerted antioxidant capacities. More importantly, the functional polymers could act as auxin analogs to increase the germination index (>100%), plant biomass, and salt tolerance of radish seedlings. Our findings disclosed that ESH could not only be optimized to mitigate the ecological risks of phenolic pollutants and sequester organic carbon in environmental bioremediation, but the resulting abundant auxin analogs also contributed to agricultural productivity.

The concept of underground gas storage is based on the natural capacity of geological formations such as aquifers, depleted oil and gas reservoirs, and salt caverns to store gases. Underground storage systems can be used to inject and store natural gas (NG) or hydrogen, which can be withdrawn for transport to end-users or for use in industrial processes. Geological formations can additionally be used to securely contain harmful gases, such as carbon dioxide, deep underground, by means of carbon capture and sequestration technologies. This paper defines and discusses underground gas storage, highlighting commercial and pilot projects and the behavior of different gases (i.e., CH4, H2, and CO2) when stored underground, as well as associated modeling investigations. For underground NG/H2 storage, the maintenance of optimal subsurface conditions for efficient gas storage necessitates the use of a cushion gas. Cushion gas is injected before the injection of the working gas (NG/H2). The behavior of cushion gas varies based on the type of gas injected. Underground NG and H2 storage systems operate similarly. However, compared to NG storage, several challenges could be faced during H2 storage due to its low molecular mass. Underground NG storage is widely recognized and utilized as a reference for subsurface H2 storage systems. Furthermore, this paper defines and briefly discusses carbon capture and sequestration underground. Most reported studies investigated the operating and cushion gas mixture. The mixture of operating and cushion gas was studied to explore how it could affect the recovered gas quality from the reservoir. The cushion gas was shown to influence the H2 capacity. By understanding and studying the different underground system technologies, future directions for better management and successful operation of such systems are thereby highlighted.

CO2-enhanced oil recovery (CO2-EOR) is a potential CO2 capture, utilization, and storage technology. In particular, CO2 can break the hydrochemical balance of water–rock and converts into carbonate minerals which are the most stable sequestration phase. The water–rock reactions are complex kinetic processes because the rate of dissolution/precipitation of minerals are vary with the pH of the formation water. However, studies on the effect of geochemical reactions on CO2-EOR processes are lacking, and the fate of CO2 cannot be accurately quantified. In this study, we combine the characteristics of the oil phase into the thermal–hydraulic–chemical TOUGHREACT simulator to consider various water–rock geochemical kinetic reactions in CO2-EOR. Therefore, the distribution phase of CO2 can be determined completely in the reservoir. Our analyses use the realistic fluid property (pressure–volume–temperature) of multicomponent oil phase–CO2 mixtures. The model considers the possible geochemical reactions and the resulting changes in porosity and permeability. The results indicate that in gas–water cycle of 9% hydrocarbon pore volume CO2 slug, the largest distributed phase of CO2 is the gas phase, accounting for 52.2% during the CO2 injection period. After water injection, the solubility of CO2 in the oil phase increases, and CO2 is mostly dissolved in the oil phase, accounting for 53.0%. Without considering the water–rock geochemical reactions will result in an underestimation of the dissolved aqueous phase and correspondingly the others were overestimated. The maximum error of the distributed quantity is up to 6.4% of the total injection. In addition, the omission of water–rock reactions result in an underestimation of the oil recovery. Comparing with the CO2 storage in a saline aquifer, dissolution of CO2 in oil phase in CO2-EOR scenario dampens the effect of buoyancy, which leads to higher sequestration capacity for the same footprint of storage reservoir.

Rapid expansion of irrigated agriculture in semi-arid regions alters the global carbon cycle and terrestrial soil carbon pools, in particular the potential for inorganic carbon sequestration in soils. Current research on soil inorganic carbon (SIC) pools in irrigated farmland focuses on local scale. The impact of irrigated agriculture on soil inorganic carbon pools and sequestration potential at the regional scale should be addressed. This study investigates soil carbon pools and inorganic carbon sequestration potential under intensive irrigated agriculture in alluvial plains in semi-arid climates. We chose the North China Plain (NCP), a traditional intensive agricultural region in China with long-term irrigation practices. Appling the national soil field survey data, we calculated soil inorganic carbon, organic carbon, estimated the content of the total soil carbon pool and the inorganic carbon sequestration potential and assessed the distribution characteristics. The SIC density and storage in fluvisols of irrigated farmland in the NCP were estimated to be 13.21 kgC·m−2 and 2.58 PgC, respectively. SIC densities accounts for 70% of the soil carbon pool. It is inferred that irrigated dryland in semi-arid regions has a considerable soil inorganic carbon pool and inorganic carbon sequestration potentials. The SIC pools in mineral soil horizon beneath plough horizon account for 75.8–78.11% of the total SIC storages. Soil inorganic carbon pools are easily lost through leaching and deposition in the lower part of the soil due to irrigation. We find that due to irrigation and atmospheric precipitation, the top layer of the soil is constantly being replenished with carbonate. Spatial distribution of inorganic carbon pools on floodplains is related to river-related geomorphology. This study provides a SIC perspective for the study of soil carbon pools in agricultural fields and complements the knowledge of carbon sequestration potential.

The world has been battling climate change which is caused by an excessive amount of carbon dioxide in the atmosphere. Carbon sequestration in geological sinks was identified as one of the major methods to curb and reduce the amount of carbon dioxide in the atmosphere. The carbon dioxide stored in the geological formations must not escape back into the atmosphere. Characterisation of potential reservoirs for geological sequestration is pertinent for injectivity, capacity, and most importantly containment of carbon dioxide. The cap rock is one of the most important factors determining carbon sequestration success. This study focuses on the preliminary characterisation of the caprocks for evaluating potential subsurface storage of carbon dioxide based on their petrophysical characteristics. X-ray Diffraction and X-ray Fluorescence provided the mineralogical composition and geochemical data of the cap rocks while Scanning Electron Microscopy-EDS was used to identify the qualitative information on the micromorphological textural structure of the cap rocks in the Niger Delta. Conventional Triaxial experiments were used to determine the elastic and geo-mechanical strength of the caprocks. It was identified that the grain skeleton of caprocks in the region is predominated by Quartz, Albite, and Muscovite. The ratio of the tectosilicate and phyllosilicate minerals indicates that the cap rocks are silicate shale. The peak strength of the caprocks ranged from 48.85 to 80.50 MPa and are classified as strong rocks. The cap rocks showed a quasi-elastic behaviour after being subjected to compressive axial force. The elastic modulus of the caprocks was also observed. The characteristics exhibited by the shale caprock at the rock matrix level are highly favourable for sealing carbon dioxide and hence indicate capability for use in carbon sequestration.

A concept has been proposed for an installation designed to store excess electricity periodically occurring on the grid. Excess electricity will be used for straw pyrolysis. The main pyrolysis product, gas, will be used to generate electricity using a combustion generator to feed back power into the grid during periods of shortage. The resulting biochar from the pyrolysis can be introduced into the soil to improve soil quality and play a significant role in carbon sequestration. The system uses an electrically heated reactor with a screw conveyor.To preliminarily assess the feasibility of this system, experiments were carried out using wheat straw at temperatures of 300, 400, 500, 600, and 700 °C for the pyrolysis reactor. The resulting gas-to-feedstock mass ratio ranged from 29.04 % at 300 °C to 52.7 % at 700 °C reactor temperature, the biochar mass yield ratio to feedstock varied from 39.41 % to 27.36 % (at 700 °C), and the pyrolysis liquid ranged from 31.55 % to 27.36 % (at 700 °C). The pyrolytic liquid contained a high water content relative to its mass, reaching up to 95.2 % at 700 °C, rendering it less suitable as an energy feedstock.At a reactor temperature of 700 °C, the energy value of the gas produced from the feedstock was twice that of the electricity used for the pyrolysis process. These results suggest the feasibility and operation of the proposed installation.

Evaluating the climate change mitigation potential of the forest sector requires a holistic approach based on forest carbon (C) sequestration, C storage in harvested wood products (HWP) and substitution on markets. High uncertainty is associated with substitution factors, that express avoided fossil greenhouse gas (GHG) emissions from the use of forest-based products in replacement of GHG-intensive materials and fossil fuels. Few studies have focused on the development of substitution factors in Canada, resulting in the use of unrepresentative generic data. Here, we provide a framework to reduce uncertainties related to substitution factors for primary wood products in a Canadian context. A life cycle assessment framework is used to quantify fossil GHG emissions for a baseline and a wood-intensive scenario. For solid product substitution, we focused on the construction sector and analyzed a range of innovative wood buildings with steel and reinforced concrete as alternative materials. We found non-weighted averages of 0.80 tC/tC for sawnwood and 0.81 tC/tC for panels. For energy substitution, we analyzed cases with different specifications on biomass product, facility type and alternative fossil fuel source in non-residential heat production and biofuel transportation sectors. We found a non-weighted average of 0.80 tC/tC for non-residential heat production and 0.51 tC/tC for biofuel transportation, that can be interpreted as 0.91 tC/tC for heavy fuel oil, 0.69 tC/tC for light fuel oil and 0.68 tC/tC for natural gas substitution. These results provide a benchmark for substitution factors in Canada, to help guide forest management strategies for climate change mitigation.

As soil fungi are major players in the carbon accumulation process, the two main fungal degraders in topsoil, Ascomycetes and Basidiomycetes, were investigated as indicators of land use effectiveness in increasing soil carbon accumulation and soil function. The study focused on the soil organic carbon content increase in a 20-year short rotation forest cycle with broadleaf woody plantations compared to a nearby arable cropping system. Total fungi, Ascomycota and Basidiomycota, were quantified in terms of DNA copy number, with specific probes using SYBR® Green I dye on the QuantStudio™ 3D digital PCR system (dPCR). Previously, next generation sequencing analysis using a general primer confirmed that Ascomycota and Basidiomycota were the most represented phyla and that fungal community composition significantly differed between treatments. A range of key soil enzyme activities for the C-cycle were also assessed. Total organic carbon content (TOC), microbial biomass in term of dsDNA and enzyme activities significantly increased in woody plantations compared to arable soil. The TOC increase differed significantly also between wood species, Salix and Robina gave the greatest increase (+30 and 20 % respectively), followed by Populus (+12), microbial biomass highly correlated with TOC showing the same trend. Total fungi, Ascomycota and Basidiomycota increased significantly in three woody plantations compared to the arable soil system. Ascomycota in the woody plantations increased two to four times (average 3144 n copies µl−1 of DNA) compared to the arable soil (1419 n copies µl−1); Basidiomycota were almost absent in arable soil (av. 94n copies µl−1) and increased five to six times in woody plantations (av. 490 n copies µl−1). Total fungi and ascomycetes correlated strongly with microbial biomass and TOC, whereas basidiomycetes did not. These findings showed that Ascomycota represent the largest portion of fungi in agricultural soils even after a 20-years short rotation forest cycle and they can be taken as indicators of carbon accumulation processes. Therefore, this study suggests that joining the Ascomycetes quantity in the topsoil to the Ascomycota:Basidiomycota ratio seems a good option when setting regional strategies for improving C accrual in farmland with the short-term afforestation.

Exploring the coupling coordinated development of carbon emission reduction and sequestration (CERS) and food security in agriculture is conducive to mitigating climate change and achieving sustainable development goals. However, there is little research on the coupling coordinated development of these two systems. Based on panel data of 31 Chinese provinces from 2001 to 2021, this study used the dynamic fuzzy set qualitative comparative analysis (fsQCA) method to analyze the levels and driving paths of coupling coordinated development between agricultural CERS and food security. The results revealed that (1) the coupling coordination degree increased from 0.443 in 2001 to 0.489 in 2021, showing an upward trend. (2) We identified three driving paths of coupling coordination development: technology-driven, finance-driven and urban-development-driven. (3) The grain sown area and unit yield are core variables, serving as fundamental pillars, and their combination with technology or financial expenditure enhances this coordinated development. Notably, the grain sown area and unit yield exhibit a complementary relationship, while agricultural technology and financial expenditure demonstrate a substitution relationship. (4) Temporal analysis showed a consistent trend in the technology-driven and finance-driven paths. Regional analysis revealed marked heterogeneity: the technology-finance synergy path predominates in the remote west, the technology-driven path lies in the mountainous southwest, the finance-driven path clusters in the north, and the urban-development-driven path is located in economically advanced regions. Policymakers should formulate policies according to these different driving paths to promote coupling coordinated development.

Grassland degradation is a prevalent issue at the interface of shrubland and grassland ecosystems, particularly susceptible to environmental changes. To counteract the degradation, grazing exclusion has been proposed as a dominant restoration strategy on the Tibetan plateau, the world's largest and highest plateau. However, the impact of degradation and subsequent restoration on the carbon dynamics consist of carbon sink / source capacity of shrub-grassland ecotones remain unclear. Therefore, in this study, using a transparent chamber (0.8 m in length × 0.8 m in width × 0.6 m in height) attached to an infrared gas analyzer, the in situ field investigation was performed to measure the gross ecosystem primary productivity (GEP), ecosystem respiration (Re), net ecosystem CO2 exchange (NEE), and environmental factors over a four-year continuous period in lightly and heavily degraded shrub-grassland ecotones during recover process on the Tibetan Plateau. Our result showed that: 1). Shrub-grassland ecotone acts as a net CO2 sink, with the maximum NEE occurring in July during the growing season. 2). Ecotone degradation diminishes the carbon sequestration capacity. Specifically, the annual GEP, Re, and NEE rates decrease by 14.1 %, 7.3 %, and 27.2 %, respectively, in the heavily degraded ecotone compared to the lightly degraded counterpart. 3). Grazing exclusion positively influenced the carbon sequestration capacity, particularly in heavily degraded ecotone, which leads to a substantial increase in the annual GEP, Re, and NEE rates of 15.4 % and 33.4 %, 12.3 % and 20.9 %, 22.25 % and 64.9 % for lightly and heavily degraded ecotones, respectively. 4). A piecewise structural equation model reveals that soil moisture and soil temperature are pivotal drivers influencing NEE. 5) Correlation analysis shows that NEE was negatively correlated with soil temperature during April to June and September to October but was positively correlated with soil temperature during July to August. In contrast, NEE displays a consistent negative correlation with soil moisture throughout the growing season. This research provides new insights on grassland degradation and restoration for carbon sequestration in alpine shrub-grassland ecotones and highlights their implications for sustainable management of alpine ecosystems.

The proteoleaginous plants demand has seen significant growth, leading to an expansion of the sunflower (Helianthus annuus, L.) and industrial hemp (Cannabis sativa, L.) cultivation area in Italy. However, by-products obtained during seed oil extraction and agricultural residues are often unused due to the absence of a receptive market and nearby processing centers. The carbon footprint (CF) methodology was used to compare the two supply chains considering the soil incorporation of all crop residues and by-products. The boundary of the supply chains analyzed includes all the agricultural processes that occur during cultivation and the subsequent oil extraction phase. Furthermore, research explored the direct and indirect environmental benefits of incorporating by-products into the soil, in terms of reducing the need for mineral fertilizers to restore soil fertility due to the nutrients contained in the buried biomass, and the potential carbon sequestration achievable. Results show that 1 kg of sunflower and hemp oil release 4.49 kg CO2-eq and 23.34 kg CO2-eq, respectively. Agriculture represents the most impacting phase and, in particular, fertilization, tillage and harvest are responsible for high emissions. The different results between the two supply chains can be attributed mainly to yield and extraction efficiency. The use of by-products as amended in the soil (avoided fertilizers) contributes to a reduction of greenhouse gas (GHG) emissions by −0.53 kg CO2-eq and −7.87 kg CO2-eq per kg of sunflower and hemp oils, respectively. Additionally, the sequestration of carbon in biomass can result in a further reduction of −1.16 and −33.6 kg CO2-eq per kg of sunflower and hemp oil, respectively. In summary, sunflower oil production emits 74 % less CO2 than hemp oil. However, if all crop biomass is buried, hemp has the potential to be more sustainable. This phenomenon depends on many factors such as soil type, climate, and farming practices. The study outcomes can aid policymakers, farmers, and the agribusiness to make informed decisions on promoting and expanding sustainable sunflower and hemp cultivation in Italy.

The Paris Agreement and the European Green Deal set ambitious climate change mitigation goals. In order to achieve these goals and offset the emissions of all other sectors significant additional carbon sequestration is needed in the land use sector. The capacity of the land use sector and especially forests to remove carbon dioxide from the atmosphere is key in climate change mitigation pathways. Well planned forest industry related measures can significantly increase carbon sequestration in living biomass as well as in harvested wood products. In our study we investigated the climate change mitigation effects of forest management systems and nature conservation conducting a Greenhouse Gas Inventory-like analysis on Hungarian forests using a forest management system and protection status specific breakdown and considering only the biomass pool. Our main conclusion was that under similar yield class distribution logging intensity and carbon sequestration are not inversely proportional. We observed that non-protected forests achieve higher net carbon sink under a higher logging intensity. Regarding forest management systems we observed significantly higher net carbon sink under transitional forest management than what was found for all other management systems. Continuous cover management and non-production forest management did not show significantly different carbon fluxes.

Mangroves, the distinctive coastal ecosystems of the tropics and sub-tropics, serve as crucial intersections between terrestrial and marine environments. In this review, we delve into the manifold roles of mangroves, showcasing their significance in environmental engineering and sustainable ecosystem practices. Historically undervalued, mangroves have undergone a renaissance in perception, with increasing recognition of their indispensable ecological services, ranging from coastal protection and blue carbon sequestration to fostering biodiversity and supporting sustainable fisheries. As we explore their potential in phytoremediation, bioremediation, urban resilience, and ecosystem-based adaptation, the synergistic relationships between mangroves and their resident microorganisms are highlighted, offering innovative avenues for environmental restoration. Additionally, the review underscores the importance of collaborative partnerships for mangrove conservation, emphasizing the need for a harmonized approach between stakeholders. In an era marked by rapid environmental changes, this review accentuates the multifunctional capability of mangroves as nature's coastal architects, advocating for their conservation and integration into sustainable ecosystem management strategies.

Improving soil quality while achieving higher productivity is the major challenge in the agricultural industry. Wheat (Triticum aestivum L.)–maize (Zea mays L.) (W–M) rotation is the dominant planting pattern in the Huang-Huai-Hai Plain and is important for food security in China. However, the soil quality is deteriorating due to the W–M rotation's long-term, intensive, and continuous cultivation. Introducing legumes into the W–M rotation system may be an effective way to improve soil quality. In this study, we aimed to verify this hypothesis by exploring efficient planting systems (wheat–peanut (Arachis hypogaea L.) (W–P) rotation and wheat rotated with maize and peanut intercropping (W–M/P)) to achieve higher agricultural production in the Huang-Huai-Hai Plain. Using traditional W–M rotation as the control, we evaluated crop productivity, net returns, soil microorganisms (SMs), and soil organic carbon (SOC) fractions for three consecutive years. The results indicated that wheat yields were significantly increased under W–P and W–M/P (382.5–579.0 and 179.8–513.1 kg ha−1, respectively) compared with W–M. W–P and W–M/P provided significantly higher net returns (58.2 and 70.4%, respectively) than W–M. W–M/P and W–M retained the SOC stock more efficiently than W–P, increasing by 25.46–31.03 and 14.47–27.64%, respectively, in the 0–20 cm soil layer. Compared with W–M, W–M/P improved labile carbon fractions; the sensitivity index of potentially mineralizable carbon, microbial biomass carbon (MBC), and dissolved organic carbon was 31.5, 96.5–157.2, and 17.8% in 20–40, 10–40, and 10–20 cm soil layers, respectively. The bacterial community composition and bacteria function were altered as per the soil depth and planting pattern. W–M/P and W–M exhibited similar bacterial community composition and function in 0–20 and 20–40 cm soil layers. Compared with W–P, a higher abundance of functional genes, namely, contains mobile elements and stress-tolerant, and a lower abundance of genes, namely, potentially pathogenic, were observed in the 10–20 cm soil layer of W–M and the 0–20 cm soil layer of W–M/P. SOC and MBC were the main factors affecting soil bacterial communities, positively correlated with Sphingomonadales and Gemmatimonadales and negatively correlated with Blastocatellales. Organic input was the main factor affecting SOC and SMs, which exhibited feedback effects on crop productivity. In summary, W–M/P improved productivity, net returns, and SOC pool compared with traditional W–M rotation systems, and it is recommended that plant–soil–microbial interactions be considered while designing high-yield cropping systems.

Due to the effects of an anthropogenic global warming, the concern about the emissions of carbon dioxide (CO2) into the environment has increased in various industries like petroleum industry. Currently, the use of the geological storage techniques, such as carbon capture and sequestration (CCS), is the most promising way to mitigate these emissions. The objective of this study on a numerical simulation is to investigate CO2 onshore geological storage in the depleted oilfields in the North of Thailand. The geological modelling is a critical step in proving the suitability of a geologic formation for a CCS project. The simulations of the pressure build-up, CO2 plume movement and the amount of CO2 stored are the main points of this research. The development of the 3D reservoir model is performed by means of CMG-GEM, and CMG-WINPROP. This study performs how CO2 sequestration is injected with the flow rate of 1000–4000 tons/day into a reservoir with a depth of 2120-2161 m. The result indicates that CO2 moves up to the top formation. Moreover, 0.583 Mt of CO2 can be stored into the reservoir. This presents the preliminary study for the CO2 sequestration in Northern Thailand, which aids in the next phase of CCS projects in Thailand.

Combined application of chemical fertilizers with organic amendments was recommended as a strategy for improving yield, soil carbon storage, and nutrient use efficiency. However, how the long-term substitution of chemical fertilizer with organic manure affects rice yield, carbon sequestration rate (CSR), and nitrogen use efficiency (NUE) while ensuring environmental safety remains unclear. This study assessed the long-term effect of substituting chemical fertilizer with organic manure on rice yield, CSR, and NUE. It also determined the optimum substitution ratio in the acidic soil of southern China. The treatments were: (i) NPK0, unfertilized control; (ii) NPK1, 100% chemical nitrogen, phosphorus, and potassium fertilizer; (iii) NPKM1, 70% chemical NPK fertilizer and 30% organic manure; (iv) NPKM2, 50% chemical NPK fertilizer and 50% organic manure; and (v) NPKM3, 30% chemical NPK fertilizer and 70% organic manure. Milk vetch and pig manure were sources of manure for early and late rice seasons, respectively. The result showed that SOC content was higher in NPKM1, NPKM2, and NPKM3 treatments than in NPK0 and NPK1 treatments. The carbon sequestration rate increased by 140, 160, and 280% under NPKM1, NPKM2, and NPKM3 treatments, respectively, compared to NPK1 treatment. Grain yield was 86.1, 93.1, 93.6, and 96.5% higher under NPK1, NPKM1, NPKM2, and NPKM3 treatments, respectively, compared to NPK0 treatment. The NUE in NPKM1, NPKM2, and NPKM3 treatments was higher as compared to NPK1 treatment for both rice seasons. Redundancy analysis revealed close positive relationships of CSR with C input, total N, soil C:N ratio, catalase, and humic acids, whereas NUE was closely related to grain yield, grain N content, and phenol oxidase. Furthermore, CSR and NUE negatively correlated with humin acid and soil C:P and N:P ratios. The technique for order of preference by similarity to ideal solution (TOPSIS) showed that NPKM3 treatment was the optimum strategy for improving CSR and NUE. Therefore, substituting 70% of chemical fertilizer with organic manure could be the best management option for increasing CSR and NUE in the paddy fields of southern China.

In order to make better use of the value of forest carbon sequestration and other aspects, this paper reformulate the forest management plan including deforestation in addition to the current conventional forest management plan. Moreover, we take into account the carbon sequestration benefits of forest products, analyze and predict the carbon sequestration amount of forests and forest products over time, and the deforestation amount including environmental damage and economic benefits, and put forward some reasonable suggestions based on the results achieved.In order to discuss the applicability of the model, we apply the model to the Greater Khingan Range to predict the carbon sequestration of the entire forest and its forest products 100 years from now, and to explore the best management options for the Greater Khingan Mountains. The result we obtain is that the final total carbon sequestration of Greater Khingan Range and their forest products is 2,461,259,714.52 tons after 100 years. Meanwhile, on the reasonable assumption that the Greater Khingan Mountains consist of only two kinds of trees, each time 0.8904% of the area of pine trees is cut, giving the forest 0.5 years of recovery time; by cutting 0.2326% of Betula platyphylla area at a time, with an interval of 0.8 years for recovery, best management is achieved.

Organic fertilization and deep ploughing are expected to contribute to carbon (C) sequestration in arable soils. This hypothesis was evaluated over 11 years of chemical and organic fertilization under conventional tillage (20 cm) and deep ploughing (40 cm) in a rainfed sorghum-maize rotation system on the Loess Plateau. Soil was collected and analysed to determine the soil organic C (SOC) and total nitrogen (TN) contents in the soil profiles (0–60 cm) or in the macroaggregates, microaggregates and silt and clay fractions (0–20 cm only). The SOC and TN stocks at the 0–60 cm depth displayed a net decrease in the unfertilized control, a marginal increase with chemical fertilizer, a significant increase of 23–45 % and 19–42 %, respectively, with organic amendments and a significant increase of 54 % and 48 %, respectively, when combined with deep ploughing. A critical input amount of 2064 kg C ha−1 yr−1 or 162 kg N ha−1 yr−1 was found to be required to maintain the initial SOC or TN stock. The annual N input was positively correlated with the C sequestration efficiency (P

Microbial residues as the key component of the stable soil organic carbon (SOC) play a critical role in stabilizing SOC, and their accumulation is influenced by plant litter. However, how the accumulation of microbial residues in different aggregate fractions of forest soils responds to changes in the inputs of leaf and root litter remains poorly understood. Here, we test the hypothesis that root exclusion has greater effects on microbial residues than leaf-litter exclusion among soil aggregate fractions based on a litter-input manipulation experiment in a subtropical coniferous forest. The concentrations of bacterial, fungal, and total microbial residues were higher in large macroaggregates (> 2000 μm) but lower in small macroaggregates (250–2000 μm). Root exclusion decreased the concentrations of bacterial, fungal, and total microbial residues in microaggregates (< 250 μm), and leaf-litter exclusion decreased fungal residues in microaggregates. Fungal residues had higher proportions to SOC (20.7–34.9%) than bacterial residues (10.8–18.6%) in soil aggregate fractions, and their proportions were higher in large macroaggregates than other aggregate fractions. Root exclusion reduced the higher proportions of bacterial, fungal, and total microbial residues to SOC in microaggregates (14.5%, 15.7%, and 15.3%, respectively), compared to the reduction observed in large macroaggregates (10.8%, 7.1%, and 8.4%, respectively). And leaf-litter exclusion reduced the proportions of fungal and total microbial residues to SOC in microaggregates. Soil microbial residue-carbon accumulation coefficient was higher in large macroaggregates and lower in small macroaggregates. The coefficient was increased by root exclusion in macroaggregates but decreased in microaggregates, and it was also decreased by leaf-litter exclusion in large macroaggregates and microaggregates. Proportions of fungal residues to SOC were more strongly related to the live microbial biomass and nutrients than those of bacterial residues. Our results suggest that root exclusion exerts stronger effects on soil microbial residues than leaf-litter exclusion but these effects vary among soil aggregate sizes.