Soil samples were taken from depth of 0-12 cm in virgin broad-leaved Korean pine mixed forest in Changbai Moun-tain in July 2000. The effects of temperature, soil water content, pH, NH4+ and NO3- on N2O emission and C...Soil samples were taken from depth of 0-12 cm in virgin broad-leaved Korean pine mixed forest in Changbai Moun-tain in July 2000. The effects of temperature, soil water content, pH, NH4+ and NO3- on N2O emission and CH4 uptake of a for-est soil were studied in laboratory by the method of orthogonal design. It was observed under laboratory conditions in this study that there were significant correlations between N2O emission rate, CH4 oxidation rate, soil pH and temperature. Nevertheless, N2O emission rate also showed a significant positive correlation with CH4 oxidation rate. The results suggested that pH and temperature were important factors controlling N2O emission and CH4 oxidation under this experiment conditions.展开更多
With global climate change, soil drying-rewetting(DRW) events have intensified and occurred frequently on the Loess Plateau of China. However, the extent to which the DRW cycles with different wetting intensities and ...With global climate change, soil drying-rewetting(DRW) events have intensified and occurred frequently on the Loess Plateau of China. However, the extent to which the DRW cycles with different wetting intensities and cycle numbers alter microbial community and respiration is barely understood. Here,indoor DRW one and four cycles treatments were implemented on soil samples obtained from the Loess Plateau, involving increase of soil moisture from10% water-holding capacity(WHC) to 60% and 90% WHC(i.e., 10%–60% and 10%–90% WHC, respectively). Constant soil moistures of 10%, 60%,and 90% WHC were used as the controls. The results showed that bacterial diversity and richness decreased and those of fungi remained unchanged under DRW treatments compared to the controls. Under all moisture levels, Actinobacteriota and Ascomycota were the most dominant bacterial and fungal phyla,respectively. The bacterial network was more complex than that of fungi, indicating that bacteria had a greater potential for interaction and niche sharing under DRW treatments. The pulse of respiration rate declined as the DRW cycle increased under 10%–60% WHC, but remained similar for different cycles under 10%–90% WHC. Moreover, the DRW treatments reduced the overall carbon loss, and the direct carbon release under 10%–60% WHC was larger than that under 10%–90% WHC. The cumulative CO_(2) emissions after four DRW cycles were significantly positively correlated with microbial biomass carbon and negatively correlated with fungal richness(Chao 1).展开更多
Nitrification inhibitors can effectively decrease nitrification rates and nitrous oxide(N_(2)O)emission while increasing crop yield under certain conditions.However,there is no information available on the effects of ...Nitrification inhibitors can effectively decrease nitrification rates and nitrous oxide(N_(2)O)emission while increasing crop yield under certain conditions.However,there is no information available on the effects of nitrification inhibitors and tillage practices on N_(2)O emissions from maize cropping in Iran.To study how tillage practices and nitrapyrin(a nitrification inhibitor)affect N_(2)O emission,a split factorial experiment using a completely randomized block design with three replications was carried out in Northeast Iran,which has a cold semiarid climate.Two main plots were created with conventional tillage and minimum tillage levels,and two nitrogen(N)fertilizer(urea)management systems(with and without nitrapyrin application)were created as subplots.Tillage level did not have any significant effect on soil ammonium(NH_(4)^(+))and nitrate(NO_(3)^(-))concentrations,cumulative amount and yield-scaled N_(2)O emission,and aboveground biomass of maize,whereas nitrapyrin application showed significant effect.Nitrapyrin application significantly reduced the cumulative amount of N_(2)O emission by 41%and 32%in conventional tillage and minimum tillage practices,respectively.A reduction in soil NO_(3)^(-)concentration by nitrapyrin was also observed.The average yield-scaled N_(2)O emission was 13.6 g N_(2)O-N kg^(-1)N uptake in both tillage systems without nitrapyrin application and was significantly reduced to 7.9 and 8.2 g N_(2)O-N kg^(-1)N uptake upon the application of nitrapyrin in minimum tillage and conventional tillage practices,respectively.Additionally,nitrapyrin application increased maize biomass yield by 4%and 13%in the minimum tillage and conventional tillage systems,respectively.Our results indicate that nitrapyrin has a potential role in reducing N_(2)O emission from agricultural systems where urea fertilizers are broadcasted,which is common in Iran due to the practice of traditional farming.展开更多
Dredged marine soils(DMS)have poor engineering properties,which limit their usage in construction projects.This research examines the application of reactive magnesia(rMgO)containing supplementary cementitious materia...Dredged marine soils(DMS)have poor engineering properties,which limit their usage in construction projects.This research examines the application of reactive magnesia(rMgO)containing supplementary cementitious materials(SCMs)to stabilize DMS under ambient and carbon dioxide(CO_(2))curing conditions.Several proprietary experimental tests were conducted to investigate the stabilized DMS.Furthermore,the carbonation-induced mineralogical,thermal,and microstructural properties change of the samples were explored.The findings show that the compressive strength of the stabilized DMS fulfilled the 7-d requirement(0.7-2.1 MPa)for pavement and building foundations.Replacing rMgO with SCMs such as biochar or ground granulated blast-furnace slag(GGBS)altered the engineering properties and particle packing of the stabilized soils,thus influencing their performances.Biochar increased the porosity of the samples,facilitating higher CO_(2) uptake and improved ductility,while GGBS decreased porosity and increased the dry density of the samples,resulting in higher strength.The addition of SCMs also enhanced the water retention capacity and modified the pH of the samples.Microstructural analysis revealed that the hydrated magnesium carbonates precipitated in the carbonated samples provided better cementation effects than brucite formed during rMgO hydration.Moreover,incorporating SCMs reduced the overall global warming potential and energy demand of the rMgO-based systems.The biochar mixes demonstrated lower toxicity and energy consumption.Ultimately,the rMgO and biochar blend can serve as an environmentally friendly additive for soft soil stabilization and permanent fixation of significant amounts of CO_(2) in soils through mineral carbonation,potentially reducing environmental pollution while meeting urbanization needs.展开更多
Aims Soil CO_(2) emission from steppes is affected by soil properties and vegetation in different successional stages.Primary and secondary succession of plants frequently occurred at the meadow steppe in Songnen Plai...Aims Soil CO_(2) emission from steppes is affected by soil properties and vegetation in different successional stages.Primary and secondary succession of plants frequently occurred at the meadow steppe in Songnen Plain,Northeast China,which indicates the large uncer-tainty associated with CO_(2) emission in this environment.This study aims to investigate the temporal variations of soil respiration(Rs)and the effect of plant succession on cumulative soil CO_(2) emission during the growing season.Methods Using a LI-6400 soil CO_(2) flux system,Rs of five vegetation types which represented different stages of plant succession in meadow steppes of Songnen Plain,China,was investigated during the grow-ing seasons of 2011 and 2012.Important Findings Soil temperature(Ts)was the dominant controlling factor of Rs,which could explain~64%of the change in CO_(2) fluxes.The Q10 values of Rs were ranged from 2.0 to 6.7,showing a decreasing trend with the plant successional stages.The cumulative CO_(2) emis-sion increased with the degree of vegetation succession and it aver-aged to 316±6 g C m^(−2)(ranges:74.8±6.7 to 516.5±11.4 g C m^(−2))during the growing season.The magnitude of soil CO_(2) emission during the growing season was positively correlated with above-ground plant biomass,soil organic carbon content and mean soil water content,while negatively linked to mean Ts,pH,electrical conductivity and exchangeable sodium percentages.The results implied that soil CO_(2) emission increased with the development of plant communities toward more advanced stages.Our findings pro-vided valuable information for understanding the variations of CO_(2) emission in the process of vegetation succession.展开更多
土壤CH_(4)和CO_(2)通量是全球碳循环的重要组成部分,是缓解和适应气候变化的关键因素,然而在不同冻融阶段土壤CH_(4)和CO_(2)通量如何响应气候变暖和氮沉降仍未清楚解析。该研究以内蒙古荒漠草原开展了18年的增温和氮沉降野外控制实验...土壤CH_(4)和CO_(2)通量是全球碳循环的重要组成部分,是缓解和适应气候变化的关键因素,然而在不同冻融阶段土壤CH_(4)和CO_(2)通量如何响应气候变暖和氮沉降仍未清楚解析。该研究以内蒙古荒漠草原开展了18年的增温和氮沉降野外控制实验为基础,使用SF-3500多通道全自动土壤气体通量测量控制系统,在2021年5月至2022年4月不间断地监测了荒漠草原生态系统土壤CH_(4)和CO_(2)通量的变化。研究结果表明:(1)增温、增温+氮添加显著提高了土壤温度,氮添加对土壤温度则没有显著影响;各处理均未改变土壤含水量。(2)荒漠草原土壤CH_(4)全年累积吸收通量为344–471 mg C·m^(-2)。增温延长了秋季冻结期,并对该时期土壤CH_(4)累积吸收通量的影响有增加趋势,氮添加和增温+氮添加则趋向于降低土壤CH_(4)吸收通量;冬季冻结期占全年土壤CH_(4)吸收通量的比例为8%,处理间差异不显著;春季解冻期对全年土壤CH_(4)吸收通量的贡献为14%,氮添加、增温+氮添加显著降低了该时期土壤CH_(4)吸收通量。(3)荒漠草原CO_(2)全年累积排放通量为101–106 g C·m^(-2);秋季冻结期排放通量占全年土壤CO_(2)排放通量的比例为5%,氮添加、增温、增温+氮添加均趋于增加土壤CO_(2)累积排放通量;土壤CO_(2)通量在冬季冻结期有从排放转变为吸收的趋势;增温、增温+氮添加在春季解冻期显著增加了土壤CO_(2)排放通量。(4)土壤CH_(4)吸收通量和CO_(2)排放通量与土壤温度和含水量呈显著正相关关系。研究结果揭示荒漠草原土壤CH_(4)通量表现为“碳汇”,特别在非生长季的土壤CH_(4)累积吸收通量对全年的贡献达到41%;土壤CO_(2)全年累积通量以排放为主,非生长季占全年土壤CO_(2)通量的比例为9%。未来应同时考虑生长季和非生长季的碳通量格局,以更精准地评估全球变化对陆地生态系统碳固持的影响。展开更多
基金This paper was supported by Chinese Academy of Sciences.
文摘Soil samples were taken from depth of 0-12 cm in virgin broad-leaved Korean pine mixed forest in Changbai Moun-tain in July 2000. The effects of temperature, soil water content, pH, NH4+ and NO3- on N2O emission and CH4 uptake of a for-est soil were studied in laboratory by the method of orthogonal design. It was observed under laboratory conditions in this study that there were significant correlations between N2O emission rate, CH4 oxidation rate, soil pH and temperature. Nevertheless, N2O emission rate also showed a significant positive correlation with CH4 oxidation rate. The results suggested that pH and temperature were important factors controlling N2O emission and CH4 oxidation under this experiment conditions.
基金supported by the Provincial Natural Science Foundation of Hunan, China (No. 2020JJ4429)the Open Fund of the State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau of China (No. A314021402-202101)the Hundred-Talent Project of Chinese Academy of Sciences (No. A315021407).
文摘With global climate change, soil drying-rewetting(DRW) events have intensified and occurred frequently on the Loess Plateau of China. However, the extent to which the DRW cycles with different wetting intensities and cycle numbers alter microbial community and respiration is barely understood. Here,indoor DRW one and four cycles treatments were implemented on soil samples obtained from the Loess Plateau, involving increase of soil moisture from10% water-holding capacity(WHC) to 60% and 90% WHC(i.e., 10%–60% and 10%–90% WHC, respectively). Constant soil moistures of 10%, 60%,and 90% WHC were used as the controls. The results showed that bacterial diversity and richness decreased and those of fungi remained unchanged under DRW treatments compared to the controls. Under all moisture levels, Actinobacteriota and Ascomycota were the most dominant bacterial and fungal phyla,respectively. The bacterial network was more complex than that of fungi, indicating that bacteria had a greater potential for interaction and niche sharing under DRW treatments. The pulse of respiration rate declined as the DRW cycle increased under 10%–60% WHC, but remained similar for different cycles under 10%–90% WHC. Moreover, the DRW treatments reduced the overall carbon loss, and the direct carbon release under 10%–60% WHC was larger than that under 10%–90% WHC. The cumulative CO_(2) emissions after four DRW cycles were significantly positively correlated with microbial biomass carbon and negatively correlated with fungal richness(Chao 1).
基金funded by the International Atomic Energy Agency,Vienna,through the coordinated research project Minimizing Farming Impacts on Climate Change by Enhancing Carbon and Nitrogen Capture and Storage in AgroEcosystems(No.18595)of Soil and Water Management and Crop Nutrition Section,Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture,Department of Nuclear Sciences and Applications,Vienna,Austria。
文摘Nitrification inhibitors can effectively decrease nitrification rates and nitrous oxide(N_(2)O)emission while increasing crop yield under certain conditions.However,there is no information available on the effects of nitrification inhibitors and tillage practices on N_(2)O emissions from maize cropping in Iran.To study how tillage practices and nitrapyrin(a nitrification inhibitor)affect N_(2)O emission,a split factorial experiment using a completely randomized block design with three replications was carried out in Northeast Iran,which has a cold semiarid climate.Two main plots were created with conventional tillage and minimum tillage levels,and two nitrogen(N)fertilizer(urea)management systems(with and without nitrapyrin application)were created as subplots.Tillage level did not have any significant effect on soil ammonium(NH_(4)^(+))and nitrate(NO_(3)^(-))concentrations,cumulative amount and yield-scaled N_(2)O emission,and aboveground biomass of maize,whereas nitrapyrin application showed significant effect.Nitrapyrin application significantly reduced the cumulative amount of N_(2)O emission by 41%and 32%in conventional tillage and minimum tillage practices,respectively.A reduction in soil NO_(3)^(-)concentration by nitrapyrin was also observed.The average yield-scaled N_(2)O emission was 13.6 g N_(2)O-N kg^(-1)N uptake in both tillage systems without nitrapyrin application and was significantly reduced to 7.9 and 8.2 g N_(2)O-N kg^(-1)N uptake upon the application of nitrapyrin in minimum tillage and conventional tillage practices,respectively.Additionally,nitrapyrin application increased maize biomass yield by 4%and 13%in the minimum tillage and conventional tillage systems,respectively.Our results indicate that nitrapyrin has a potential role in reducing N_(2)O emission from agricultural systems where urea fertilizers are broadcasted,which is common in Iran due to the practice of traditional farming.
基金This work was supported by the Creative Groups of Natural Science Foundation of Hubei Province(Grant No.2021CFA030).Onyekwena Chikezie Chimere is an awardee for the ANSO Scholarship 2020-PhD.Ishrat Hameed Alvi is a recipient of the 2021 PhD ANSO Scholarship.
文摘Dredged marine soils(DMS)have poor engineering properties,which limit their usage in construction projects.This research examines the application of reactive magnesia(rMgO)containing supplementary cementitious materials(SCMs)to stabilize DMS under ambient and carbon dioxide(CO_(2))curing conditions.Several proprietary experimental tests were conducted to investigate the stabilized DMS.Furthermore,the carbonation-induced mineralogical,thermal,and microstructural properties change of the samples were explored.The findings show that the compressive strength of the stabilized DMS fulfilled the 7-d requirement(0.7-2.1 MPa)for pavement and building foundations.Replacing rMgO with SCMs such as biochar or ground granulated blast-furnace slag(GGBS)altered the engineering properties and particle packing of the stabilized soils,thus influencing their performances.Biochar increased the porosity of the samples,facilitating higher CO_(2) uptake and improved ductility,while GGBS decreased porosity and increased the dry density of the samples,resulting in higher strength.The addition of SCMs also enhanced the water retention capacity and modified the pH of the samples.Microstructural analysis revealed that the hydrated magnesium carbonates precipitated in the carbonated samples provided better cementation effects than brucite formed during rMgO hydration.Moreover,incorporating SCMs reduced the overall global warming potential and energy demand of the rMgO-based systems.The biochar mixes demonstrated lower toxicity and energy consumption.Ultimately,the rMgO and biochar blend can serve as an environmentally friendly additive for soft soil stabilization and permanent fixation of significant amounts of CO_(2) in soils through mineral carbonation,potentially reducing environmental pollution while meeting urbanization needs.
基金National Natural Science Foundation of China(31100403,41101207)Special Fund for Agro-scientific Research in the Public Interest,China(201303095-8).
文摘Aims Soil CO_(2) emission from steppes is affected by soil properties and vegetation in different successional stages.Primary and secondary succession of plants frequently occurred at the meadow steppe in Songnen Plain,Northeast China,which indicates the large uncer-tainty associated with CO_(2) emission in this environment.This study aims to investigate the temporal variations of soil respiration(Rs)and the effect of plant succession on cumulative soil CO_(2) emission during the growing season.Methods Using a LI-6400 soil CO_(2) flux system,Rs of five vegetation types which represented different stages of plant succession in meadow steppes of Songnen Plain,China,was investigated during the grow-ing seasons of 2011 and 2012.Important Findings Soil temperature(Ts)was the dominant controlling factor of Rs,which could explain~64%of the change in CO_(2) fluxes.The Q10 values of Rs were ranged from 2.0 to 6.7,showing a decreasing trend with the plant successional stages.The cumulative CO_(2) emis-sion increased with the degree of vegetation succession and it aver-aged to 316±6 g C m^(−2)(ranges:74.8±6.7 to 516.5±11.4 g C m^(−2))during the growing season.The magnitude of soil CO_(2) emission during the growing season was positively correlated with above-ground plant biomass,soil organic carbon content and mean soil water content,while negatively linked to mean Ts,pH,electrical conductivity and exchangeable sodium percentages.The results implied that soil CO_(2) emission increased with the development of plant communities toward more advanced stages.Our findings pro-vided valuable information for understanding the variations of CO_(2) emission in the process of vegetation succession.
文摘土壤CH_(4)和CO_(2)通量是全球碳循环的重要组成部分,是缓解和适应气候变化的关键因素,然而在不同冻融阶段土壤CH_(4)和CO_(2)通量如何响应气候变暖和氮沉降仍未清楚解析。该研究以内蒙古荒漠草原开展了18年的增温和氮沉降野外控制实验为基础,使用SF-3500多通道全自动土壤气体通量测量控制系统,在2021年5月至2022年4月不间断地监测了荒漠草原生态系统土壤CH_(4)和CO_(2)通量的变化。研究结果表明:(1)增温、增温+氮添加显著提高了土壤温度,氮添加对土壤温度则没有显著影响;各处理均未改变土壤含水量。(2)荒漠草原土壤CH_(4)全年累积吸收通量为344–471 mg C·m^(-2)。增温延长了秋季冻结期,并对该时期土壤CH_(4)累积吸收通量的影响有增加趋势,氮添加和增温+氮添加则趋向于降低土壤CH_(4)吸收通量;冬季冻结期占全年土壤CH_(4)吸收通量的比例为8%,处理间差异不显著;春季解冻期对全年土壤CH_(4)吸收通量的贡献为14%,氮添加、增温+氮添加显著降低了该时期土壤CH_(4)吸收通量。(3)荒漠草原CO_(2)全年累积排放通量为101–106 g C·m^(-2);秋季冻结期排放通量占全年土壤CO_(2)排放通量的比例为5%,氮添加、增温、增温+氮添加均趋于增加土壤CO_(2)累积排放通量;土壤CO_(2)通量在冬季冻结期有从排放转变为吸收的趋势;增温、增温+氮添加在春季解冻期显著增加了土壤CO_(2)排放通量。(4)土壤CH_(4)吸收通量和CO_(2)排放通量与土壤温度和含水量呈显著正相关关系。研究结果揭示荒漠草原土壤CH_(4)通量表现为“碳汇”,特别在非生长季的土壤CH_(4)累积吸收通量对全年的贡献达到41%;土壤CO_(2)全年累积通量以排放为主,非生长季占全年土壤CO_(2)通量的比例为9%。未来应同时考虑生长季和非生长季的碳通量格局,以更精准地评估全球变化对陆地生态系统碳固持的影响。
