Effects of soil nitrate:ammonium ratio on plant carbon:nitrogen ratio and growth rate of Artemisia sphaerocephala seedlings

Can soil nitrate： ammonium ratios influence plant carbon： nitrogen ratios of the early succession plant？ Can plant carbon： nitrogen ratios limit the plant growth in early succession？ To address these two questions, we performed a two-factor （soil nitrate： ammonium ratio and plant density） randomized block design and a uniform-precision rotatable central composite design pot experiments to examine the relationships between soil nitrate： ammonium ratios, the carbon： nitrogen ratios and growth rate of Artemisia sphaerocephala seedlings. Under adequate nutrient status, both soil nitrate： ammonium ratios and plant density influenced the carbon： nitrogen ratios and growth rate of A. sphaerocephala seedlings. Under the lower soil nitrate： ammonium ratios, with the increase of soil nitrate： ammonium ratios, the growth rates of plant height and shoot biomass of A. sphaerocephala seedlings decreased significantly; with the increase of plant carbon： nitrogen ratios, the growth rates of shoot biomass of A. sphaerocephala seedlings decreased significantly. Soil nitrate： ammonium ratios affected the carbon： nitrogen ratios of A. sphaerocephala seedlings by plant nitrogen but not by plant carbon. Thus, soil nitrate： ammonium ratios influenced the carbon： nitrogen ratios of A. sphaerocephala seedlings, and hence influenced its growth rates. Our results suggest that under adequate nutrient environment, soil nitrate： ammonium ratios can be a limiting factor for the growth of the early succession plant.

Carbon Footprint in Waste Sector of Hydropower Plant: A Case Study of Nam Theun 2 Hydropower Plant

While hydropower is generally considered a clean energy source, it is important to recognize that their waste can still contribute to greenhouse gas emissions (GHG). The purpose of this study is to assess the carbon footprint associated with the waste sector throughout the operational phase of the Nam Theun 2 hydropower plant in Laos. Understanding the environmental impact of the waste sector is crucial for ensuring the plant’s sustainability. This study utilizes the theoretical estimation method recommended in the 2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories, as well as the Requirements for Specification with guidance at the organization level for quantification and reporting of GHG emissions and removals. We emphasize the significance of implementing sustainable waste management practices to reduce GHG emissions and minimize the environmental impact of hydropower operations. By conducting a comprehensive analysis, this paper also provides insights into the environmental implications of waste management in hydropower plants and identifies strategies to mitigate the carbon footprint in the waste sector. The findings contribute to a better understanding of the environmental sustainability of hydropower plants and provide valuable guidance for policymakers, energy producers, and environmental practitioners involved in hydropower plant design and operation.

Synthesis of Fluorescent Carbon Quantum Dots and Their Application in the Plant Cell Imaging

Carbon quantum dots(CQDs) exhibit tremendous advantages for plant growth study due to its strong fluorescence and good biocompatibility. The fluorescent CQDs were synthesized by the onestep microwave method with the raw materials of citric acid(CA) and urea(UR), and expressed a unique green fluorescence with the optimal excitation wavelength of over 400 nm through adjusting the doping of N elements. It is demonstrated that CQDs can act as deliver media in plant and fluorescent probes for plant cell imaging through directly cultivated in the seedlings of melon and wheat, respectively. Based on the effects of the fluorescent CQDs on plants growth, we can further study the mechanisms of the ions transport in plants.

Comparison of Carbon, Nitrogen, and Sulfur in Coastal Wetlands Dominated by Native and Invasive Plants in the Yancheng National Nature Reserve, China

The rapid invasion of the plant Spartina alterniflora in coastal wetland areas can threaten the capacity of their soils to store carbon(C),nitrogen(N),and sulfur(S).In this study,we investigated the spatial and temporal distribution patterns of C,N and S of both soil and(native and invasive)plants in four typical coastal wetlands in the core area of the Yancheng National Nature Reserve,China.The results show that the invasive S.alterniflora greatly influenced soil properties and increased soil C,N and S storage capacity:the stock(mean±standard error)of soil organic carbon(SOC,(3.56±0.36)kg/m^3),total nitrogen(TN,(0.43±0.02)kg/m^3),and total sulfur(TS,(0.69±0.11)kg/m^3)in the S.alterniflora marsh exceeded those in the adjacent bare mudflat,Suaeda salsa marsh,and Phragmites australis marsh.Because of its greater biomass,plant C((1193.7±133.6)g/m^2),N((18.8±2.4)g/m^2),and S((9.4±1.5)g/m^2)storage of S.alterniflora was also larger than those of co-occurring native plants.More biogenic elements circulated in the soil-plant system of the S.alterniflora marsh,and their spatial and temporal distribution patterns were also changed by the S.alterniflora invasion.Soil properties changed by S.alterniflora’s invasion thereby indirectly affected the accumulation of soil C,N and S in this wetland ecosystem.The SOC,TN,and TS contents were positively correlated with soil electrical conductivity and moisture,but negatively correlated with the pH and bulk density of soil.Together,these results indicate that S.alterniflora invasion altered ecosystem processes,resulted in changes in net primary production and litter decomposition,and increased the soil C,N and S storage capacity in the invaded ecosystems in comparison to those with native tallgrass communities in the coastal wetlands of East China.

Evaluation Indicator System of Low-carbon Landscape in Residential Areas: A Case Study of Garden Plant Landscape

Garden plant landscape is one of the main contents of low-carbon landscape design in residential areas. From the basic theory of garden plant landscaping, we put forth five principles and ideas concerning the building of evaluation indicator system of garden plant landscape, to establish the indicator system with ecological quality, recreational function and aesthetic effect as three layers. According to the characteristics of evaluation system, we use qualitative and quantitative integration method, coupled with analytic hierarchy process (AHP) and expert consulting method, to determine the weight of various factors. And we use fuzzy comprehensive evaluation method to test this indicator system, so as to provide a theoretical basis for the research on evaluation indicator system of low-carbon landscape.

Stable Carbon Isotope and Long-Chain Alkane Compositions of the Major Plants and Sediment Organic Matter in the Yellow River Estuarine Wetlands

Elemental(TOC,TN,C/N)and stable carbon isotopic(δ^13C)compositions and long-chain alkane(n C16-38)concentrations were measured for eight major plants and a sediment core collected from the Yellow River estuarine wetlands.Our results indicate that both C3(-25.4‰to-29.6‰)and C4(-14.2‰to-15.0‰)plants are growing in the wetlands and C3 plants are the predominant species.The biomass of the wetland plants had similar organic carbon(35.5-45.8%)but very different organic nitrogen(0.35-4.15%)contents.Both C3 and C4 plants all contained long-chain alkanes with strong odd-to-even carbon numbered chain predominance.Phragmites australis,a dominant C3 plant contained mainly n C29 and n C31 homologues.Aeluropus littoralis,an abundant C4 plant were concentrated with n C27 and n C29 homologues.Organic matter preserved in the Yellow River estuarine sediments showed strong terrestrial signals(C/N=11-16,δ^13C=-22.0‰to-24.3‰).The distribution of long-chain n-alkanes in sediments also showed strong odd-to-even carbon chain predominance with n C29 and n C31 being the most abundant homologues.These results suggest that organic matter preserved in the Yellow River estuarine sediments were influenced by the wetland-derived organic matter,mainly C3 plants.The Yellow River estuarine wetland plants could play important role affecting both the carbon and nutrient cycling in the estuary and adjacent coastal waters.

Plant Responses to Carbon Dioxide Releasedfrom Piggery

In the present study, lean-to greenhouses were built by sharing a wall of piggeries. The vents in the wall allowed the air exchange between the piggeries and the greenhouses, so that carbon dioxide(CO_2) could be released from the piggeries to the greenhouses, and oxygen(O_2) could be released from the greenhouses to the piggeries. In the greenhouses, tomato, Chinese cabbage and muskmelon were planted and their quality indices were determined to evaluate their response to elevated CO_2. The results showed that the CO_2 concentration in greenhouse was increased, and under such conditions the yield and quality of all tomato, Chinese cabbage and muskmelon were improved.

Development of Carbon Dioxide Capture Technologies in Coal-Fired Power Plants

With a particular reference to China Huaneng Group's practices in CO_2 capture, this article presents a brief ing on the current development of CO_2 capture technologies in coal-fired power plants both in China and abroad. Sooner or later, the integration of CO_2 capture and storage (CCS) facility with coal-fired power plant will be inevitably put on the agenda of developers.

Low-Carbon Dispatch of an Integrated Energy System Considering Confidence Intervals for Renewable Energy Generation

Addressing the insufficiency in down-regulation leeway within integrated energy systems stemming from the erratic and volatile nature of wind and solar renewable energy generation,this study focuses on formulating a coordinated strategy involving the carbon capture unit of the integrated energy system and the resources on the load storage side.A scheduling model is devised that takes into account the confidence interval associated with renewable energy generation,with the overarching goal of optimizing the system for low-carbon operation.To begin with,an in-depth analysis is conducted on the temporal energy-shifting attributes and the low-carbon modulation mechanisms exhibited by the source-side carbon capture power plant within the context of integrated and adaptable operational paradigms.Drawing from this analysis,a model is devised to represent the adjustable resources on the charge-storage side,predicated on the principles of electro-thermal coupling within the energy system.Subsequently,the dissimilarities in the confidence intervals of renewable energy generation are considered,leading to the proposition of a flexible upper threshold for the confidence interval.Building on this,a low-carbon dispatch model is established for the integrated energy system,factoring in the margin allowed by the adjustable resources.In the final phase,a simulation is performed on a regional electric heating integrated energy system.This simulation seeks to assess the impact of source-load-storage coordination on the system’s low-carbon operation across various scenarios of reduction margin reserves.The findings underscore that the proactive scheduling model incorporating confidence interval considerations for reduction margin reserves effectively mitigates the uncertainties tied to renewable energy generation.Through harmonized orchestration of source,load,and storage elements,it expands the utilization scope for renewable energy,safeguards the economic efficiency of system operations under low-carbon emission conditions,and empirically validates the soundness and efficacy of the proposed approach.

Collaborative robust dispatch of electricity and carbon under carbon allowance trading market

The launch of the carbon-allowance trading market has changed the cost structure of the power industry.There is an asynchronous coupling mechanism between the carbon-allowance-trading market and the day-ahead power-system dispatch.In this study,a data-driven model of the uncertainty in the annual carbon price was created.Subsequently,a collaborative,robust dispatch model was constructed considering the annual uncertainty of the carbon price and the daily uncertainty of renewable-energy generation.The model is solved using the column-and-constraint generation algorithm.An operation and cost model of a carbon-capture power plant(CCPP)that couples the carbon market and the economic operation of the power system is also established.The critical,profitable conditions for the economic operation of the CCPP were derived.Case studies demonstrated that the proposed low-carbon,robust dispatch model reduced carbon emissions by 2.67%compared with the traditional,economic,dispatch method.The total fuel cost of generation decreases with decreasing,conservative,carbon-price-uncertainty levels,while total carbon emissions continue to increase.When the carbon-quota coefficient decreases,the system dispatch tends to increase low-carbon unit output.This study can provide important guidance for carbon-market design and the low-carbon-dispatch selection strategies.

Plant Cultivation: A Strong and Sustainable Response to CO2 Emissions

According to the quantities of plant and animal products placed on the world market in 2022, agriculture and forestry captured 20.1 ± 1.5 billion tonnes (Gt or Pg) of CO2, with a weighted mean duration of the corresponding storage of 10.9 ± 3.3 years. These figures are supplemented here by the unharvested above-ground and below-ground parts of plants that are left in place and increase the soil organic carbon pool. This brings the capture by cultivated whole plants to 41.0 ± 0.6 GtCO2, and the storage duration weighted mean to 26.3 ± 2.0 years in 2022. This was the largest global contribution to the reduction of atmospheric CO2 by amplitude and duration, which bio-remediated the global anthropogenic emissions totally, cancelling their influence on climate. The enrichment of the atmosphere with CO2 comes probably from the ocean, which could be a source and not a sink. Complementary approaches, freed from doctrinal preconceptions, should make it possible to clarify further the compensations of CO2 emissions by plants and their environmental consequences.

Study on Modern Plant C-13 in Western China and Its Significance

Organic carbon isotopic composition ({δ+{13}C}) is one of the important proxies in paleoenvironment studies. In this paper modern plant {δ+{13}C} in the arid areas of China and Tibetan Plateau is studied. It is found that most terrestrial plant species in western China are C-3 plants with {δ+{13}C} values ranging from {-32.6‰} to {-23.2‰} and only few species are C-4 plants with {δ+{13}C} values from {-16.8‰} to {-13.3‰}. The {δ+{13}C} is closely related to precipitation (or humidity), i.e., light {δ+{13}C} is related to high precipitation (or humid climate), while heavy {δ+{13}C} to low precipitation (or dry climate), but there is almost no relation between plant {δ+{13}C} and temperature. Submerged plants have {δ+{13}C} values ranging from {-22.0‰} to {-12.7‰}, like C-4 plants, while merged plants have {δ+{13}C} values ranging from {-28.1‰} to {-24.5‰}, like C-3 plants. It can then be concluded that organic {δ+{13}C} variations in terrestrial sediments such as loess and soil in western China can indicate precipitation changes, but those in lake sediments can reflect organic sources and the productivity of different types of aquatic plants.

Environmental life cycle assessment of Indian coal-fired power plants

Coal is the backbone of the Indian power sector. The coal-fired power plants remain the largest emitters of carbon dioxide, sulfur dioxide and substantial amounts of nitrogen oxides, which are associated with climate and health impacts. Various CO2 mitigation technologies （carbon capture and storage--CCS） and SO2/NOx mitigation technologies （flue gas desulfurization and selective catalytic reduction） have been employed to reduce the environmental impacts of the coal-fired power plants. Therefore, it is imperative to understand the feasibility of various mitigation technologies employed. This paper attempts to perform environmental life cycle assessment （LCA） of Indian coal-fired power plant with and without CO2, SO2 and NOx mitigation controls. The study develops new normalization factors for India in various damage categories, using the Indian emissions and energy consumption data, coupled with the emissions and particulate emission to come up with a final environmental impact of coal-fired electricity. The results show a large degree of dependence on the perspective of assessment used. The impact of sensitivities of individual substances and the effect of plant efficiency on the final LCA results is also studied.

Effects of vegetable oil residue after soil extraction on physical-chemical properties of sandy soil and plant growth

Vegetable oil has the ability to extract polycyclic aromatic hydrocarbons(PAHs)from contaminated sandy soil for a remediation purpose,with some of the oil remaining in the soil.Although most of the PAHs were removed,the risk of residue oil in the soil was not known.The objective of this study was to evaluate the effects of the vegetable oil residue on higher plant growth and sandy soil properties after soil extraction for a better understanding of the soil remediation.Addition of sunflower oil and column ex...

Soil Organic Carbon Contents and Stocks in Coastal Salt Marshes with Spartina alterniflora Following an Invasion Chronosequence in the Yellow River Delta,China

Plant invasion alters the fundamental structure and function of native ecosystems by affecting the biogeochemical pools and fluxes of materials and energy. Native(Suaeda salsa) and invasive(Spartina alterniflora) salt marshes were selected to study the effects of Spartina alterniflora invasion on soil organic carbon(SOC) contents and stocks in the Yellow River Delta. Results showed that the SOC contents(g/kg) and stocks(kg/m^2) were significantly increased(P < 0.05) after Spartina alterniflora invasion of seven years, especially for the surface soil layer(0–20 cm). The SOC contents exhibited an even distribution along the soil profiles in native salt marshes, while the SOC contents were gradually decreased with depth after Spartina alterniflora invasion of seven years. The natural ln response ratios(Ln RR) were applied to identify the effects of short-term Spartina alterniflora invasion on the SOC stocks. We also found that Spartina alterniflora invasion might cause soil organic carbon losses in a short-term phase(2–4 years in this study) due to the negative Ln RR values, especially for 20–60 cm depth. And the SOCD in surface layer(0–20 cm) do not increase linearly with the invasive age. Spearman correlation analysis revealed that silt + clay content was exponentially related with SOC in surface layer(Adjusted R^2 = 0.43, P < 0.001), suggesting that soil texture could play a key role in SOC sequestration of coastal salt marshes.

Effects of prescribed burning on carbon accumulation in two paired vegetation sites in subtropical China

Background: Prescribed burning is a common practice of site preparation before afforestation in subtropical forests. However, the effects of prescribed burning on carbon (C) dynamics of an ecosystem are poorly understood. Therefore, a Eucalyptus urophylla plantation (EU) and a naturally recovered shrubland (NS), each treated with prescribed burning and no burning were examined in subtropical China. Methods: Biomass of trees and shrubs in the 1st, 3nd, 4th, and 6th year after treatments were estimated by quadrat survey and allometric equations. Biomass of herbs and forest floors were estimated by harvest method. Plant biomass C storage was calculated by plant biomass multiplying by its C concentration. Soil organic C (SOC) storage in the 6th year after treatments was estimated by SOC concentration multiplying by soil bulk density and soil volumes. Results: Tree biomass C storage was significantly higher in the burned EU (BEU) than in the unburned EU (UEU) in the 1st year after treatments, yet the difference decreased over time. Conversely, tree biomass C storage was lower in the burned NS (BNS) than in the unburned NS (UNS), although the difference was not significant. However, in the 6th year after treatments, the total plant biomass C storage was 14.56% higher in the BEU than that in the UEU, and 59.93% higher in the BNS than that in the UNS, respectively, although the significant difference was only found between UNS and BNS. In addition, neither SOC storage at 0-20 cm nor ecosystem C storage in either the EU or NS was significantly affected by prescribed burning. Conclusions: Prescribed burning has little impact on overall C storage of forest ecosystems, we consider that prescribed burning may be an option for forest site preparation regarding plant biomass C accumulation.

Interaction effect of nitrogen form and planting density on plant growth and nutrient uptake in maize seedlings

High planting density is essential to increasing maize grain yield.However,single plants suffer from insufficient light under high planting density.Ammonium(NH_4^+)assimilation consumes less energy converted from radiation than nitrateIt is hypothesized that a mixed NO_3~–/NH_4^+supply is more important to improving plant growth and population productivity under high vs.low planting density.Maize plants were grown under hydroponic conditions at two planting densities(low density:only).A significant interaction effect was found between planting density and N form on plant biomass.Compared to nitrate only,75/25NO_3~–/NH_4^+increased per-plant biomass by 44%under low density,but by 81%under high density.Treatment with 75/25NO_3~–/NH_4^+increased plant ATP,photosynthetic rate,and carbon amount per plant by 31,7,and 44%under low density,respectively,but by 51,23,and 95%under high density.Accordingly,carbon level per plant under 75/25NO_3~–/NH_4^+was improved,which increased leaf area,specific leaf weight and total root length,especially for high planting density,increased by 57,17 and 63%,respectively.Furthermore,under low density,75/25NO_3~–/NH_4^+increased nitrogen uptake rate,while under high density,75/25NO_3~–/NH_4^+increased nitrogen,phosphorus,copper and iron uptake rates.By increasing energy use efficiency,an optimum NO_3~–/NH_4^+ratio can improve plant growth and nutrient uptake efficiency,especially under high planting density.In summary,an appropriate supply of NH_4^+in addition to nitrate can greatly improve plant growth and promote population productivity of maize under high planting density,and therefore a mixed N form is recommended for high-yielding maize management in the field.

考虑风电爬坡灵活调节的碳捕集电厂低碳经济调度

为实现“双碳”目标,风电等可再生能源的使用是减少碳排放的根本途径,而碳捕集电厂是降低碳排放的直接手段。但风电具有与生俱来的波动性,风电的骤升骤降会影响碳捕集电厂“电碳耦合”特性,从而对碳捕集效果带来不利影响。而储液罐通过增减自身溶液量可近似地存储释放能量,为解决上述问题提供了可能。该文首先搭建碳捕集电厂数学模型,分析储液罐通过增减溶液量带来的储放能量与碳捕集设备能耗之间的关联,研究储液罐的双向调节能力;然后,提出上爬坡碳超前补偿和下爬坡碳滞后补偿调度策略,双向调节储液罐使碳捕集电厂电碳解耦;接着,构建跟随风电爬坡进行调节的低碳经济调度模型;最后,对含碳捕集电厂、高碳电厂和风电场的电力系统进行仿真,证明所提方法的有效性。

利用农业废弃物强化人工湿地处理污水处理厂尾水机理研究

为研究3种典型的农业废弃物(玉米芯、玉米秸秆和小麦秸秆)作为人工湿地外加碳源脱氮的可行性,利用三维荧光和高通量测序分析了植物碳源在人工湿地中促进废水脱氮的增强机制。结果表明:农业废弃物材料可以很好地释放有机碳,累计碳释放量为119.78~172.84 mg·g^(-1),同时分解释放的溶解性有机物(Dissolved organic matter,DOMs)主要由腐植酸和黄腐酸组成。在添加农业废弃物的人工湿地中,TN去除效率提高了30.8%~41.2%,并且脱氮菌属Pseudomonas、Thauera等的相对丰度提高了16.38%~22.02%。添加玉米秸秆的人工湿地具有较好的脱氮效果。研究表明,利用农业废弃物作为人工湿地外部碳源处理污水处理厂尾水,可以显著降低尾水中TN,这也为农业废弃物的处理找到了一个新的出路。