The forest ecosystem plays an important role in the global carbon cycling. A study was conducted to evaluate soil CO2 flux and its seasonal and diurnal variation with the air and soil temperatures by using static clos...The forest ecosystem plays an important role in the global carbon cycling. A study was conducted to evaluate soil CO2 flux and its seasonal and diurnal variation with the air and soil temperatures by using static closed chamber technique in a typical broad-leaved/Korean pine mixed forest area on the northern slope of Changbai Mountain, Jilin Province, China. The experiment was carried out through the day and night in the growing season (from June to September) in situ and sample gas was analyzed by a gas chromatograph. Results showed that the forest floor was a large net source of carbon, and soil CO2 fluxes had an obvi-ous law of seasonal and diel variation. The soil CO2 flux of broad-leaved/Korean pine mixed forest was in the range of 0.302.42 mmol穖-2穝-1 with the mean value of 0.98 mmol穖-2穝-1. An examination on the seasonal pattern of soil CO2 emission suggested that the variability in soil CO2 flux could be correlated with variations in soil temperature, and the maximum of mean CO2 flux occurred in July ((1.27±23%) mmol穖-2穝-1) and the minimum was in September ((0.50±28%) mmol穖-2穝-1). The fluctuations in diel soil CO2 flux were also correlated with changes in soil temperature; however, there existed a factor for a time lag. Soil CO2 flux from the forest floor was strongly related to soil temperature and had the highest correlation with temperature at 6-cm depth of soil. Q10 values based on air temperature and soil temperature of different soil depths were at the ranges of 2.09–3.40.展开更多
[Objective] The aim was to overview the emission of greenhouse gases in farmland. [Method] Based on domestic and foreign references, production mechanism, discharging characters and major influential factors of CO2, C...[Objective] The aim was to overview the emission of greenhouse gases in farmland. [Method] Based on domestic and foreign references, production mechanism, discharging characters and major influential factors of CO2, CH4 and N2O in soils of farmland were overviewed. [Result] Production and discharge of CO2, CH. and N2O played an important role in circulation of carbon and nitrogen in terrestrial ecosystem and constituted a key method for carbon and nitrogen output. It is significant to conduct research on reduction of greenhouse gas and increase of absorption. [Conclusion] The research is beneficial for exploration on discharge rule and influential factors of greenhouse gases, providing theoretical references for reduction of greenhouse gases and study on climate change.展开更多
Soil samples were taken from an Ermans birch （Betula ermanii）-dark coniferous forest （Picea jezoensis and Abies nephrolepis） ecotone growing on volcanic ejecta in the northern slope of Changbai Mountains of Northe...Soil samples were taken from an Ermans birch （Betula ermanii）-dark coniferous forest （Picea jezoensis and Abies nephrolepis） ecotone growing on volcanic ejecta in the northern slope of Changbai Mountains of Northeast China, to compare soil carbon （C） and nitrogen （N） transformations in the two forests. The soil type is Umbri-Gelic Cambosols in Chinese Soil Taxonomy. Soil samples were incubated aerobically at 20℃ and field capacity of 700 g kg^-1 over a period of 27 weeks. The amount of soil microbial biomass and net N mineralization were higher in the Ermans birch than the dark coniferous forest （P 〈 0.05）, whereas the cumulative C mineralization （as CO2 emission） in the dark coniferous forest exceeded that in the Ermans birch （P 〈 0.05）. Release of the cumulative dissolved organic C and dissolved organic N were greater in the Ermans birch than the dark coniferous forest （P 〈 0.05）. The results suggested that differences of forest types could result in considerable change in soil C and N transformations.展开更多
Rice paddies are increasingly being converted to vegetable production due to economic benefits related,in part,to changes in demand during recent decades.Here,we implemented a parallel field experiment to simultaneous...Rice paddies are increasingly being converted to vegetable production due to economic benefits related,in part,to changes in demand during recent decades.Here,we implemented a parallel field experiment to simultaneously measure annual emissions of CH_4and N_2O,and soil organic carbon(SOC)stock changes,in rice paddies(RP),rice paddy–converted conventional vegetable fields(CV),and rice paddy–converted greenhouse vegetable fields(GV).Changing from rice to vegetable production reduced CH_4emissions by nearly 100%,and also triggered substantial N_2O emissions.Furthermore,annual N_2O emissions from GV significantly exceeded those from CV due to lower soil p H and higher soil temperature.Marginal SOC losses occurred after one year of cultivation of RP,CV,and GV,contributing an important share(3.4%,32.2%,and 10.3%,respectively)of the overall global warming potential(GWP)balance.The decline in CH_4emissions outweighed the increased N_2O emissions and SOC losses in CV and GV,leading to a 13%–30%reduction in annual GWP as compared to RP.These results suggest that large-scale expansion of vegetable production at the expense of rice paddies is beneficial for mitigating climate change in terms of the overall GWP.展开更多
The recovering logged-over forest ecosystem increases the CO2 efflux into the atmospheric carbon pool in response to environmental factors to changes in the soil temperature and moisture. These CO2 outbursts can have ...The recovering logged-over forest ecosystem increases the CO2 efflux into the atmospheric carbon pool in response to environmental factors to changes in the soil temperature and moisture. These CO2 outbursts can have a marked influence on the ecosystem carbon balance and thereby affect the atmospheric carbon pool. The study was conducted in the 10-year-old logged-over forest of Sungai Menyala forest, Port Dickson, Negeri Sembilan, Malaysia. The measurements of soil CO2 efflux were conducted using the continuous open flow chamber technique connected to a multi gas-handling unit and infrared CO2/H2O gas analyser. The aim of this study was to determine the soil CO2 efflux and the environmental variables and likewise the impact of environmental factors on soil CO2 efflux. Post-hoc comparisons were made using the Tukey test （p 〈 0.05）, and multiple linear regression to determine the impact of environmental factors on soil CO2 efflux. Soil CO2 efflux ranged from 100.22-553.40 mg m^-2 h^-1 with the highest efflux in the afternoon attributed to an increase in soil temperature and low moisture. A higher soil temperature and low moisture signify an influential factor as the forest is recovering from logging activity. Furthermore, the predictor environmental variables： SOC （soil organic carbon）, TOC （total organic carbon）, SMC （soil moisture content）, Bulk Density, SOCstock （soil organic carbon stock）, TAGB （total above ground carbon biomass）, Below Ground Carbon Biomass, soil pH, Nitrogen to Carbon ratio account for the spatial and temporal variation in soil CO： efflux into the atmosphere. The analysis revealed a strong correlation between soil CO2 efflux, changes soil properties and environmental factors with an R^2 more than 0.80 at p 〈 0.01. This is proven that logging activity accounts for the changes in environmental factors to influence soil CO2 efflux rate within 10-years of logging and forest recovering.展开更多
Invasive alien plants not only decrease riparian vegetation diversity but also alter wetland ecosystem carbon processes,especially when they displace the original vegetation.Invasive Canada goldenrod(Solidago canadens...Invasive alien plants not only decrease riparian vegetation diversity but also alter wetland ecosystem carbon processes,especially when they displace the original vegetation.Invasive Canada goldenrod(Solidago canadensis L.)has colonized large areas of disturbed and undisturbed land in southeastern China,yet little is known regarding how it affects soil carbon cycling.To explore the response patterns of soil respiration following S.canadensis invasion and their driving mechanisms,an observational field study and a greenhouse experiment simulating invasion were performed.In the field study,soil respiration was measured weekly from 21th July 2018 to 15th December 2018.In the greenhouse experiment,soil,autotrophic and heterotrophic respiration were measured every 1st and 15th of the month from 15th July 2019 to 15th December 2019.Soil,autotrophic and heterotrophic respiration were measured using a closed-chamber system with the deep gauze collar root exclusion method.Solidago canadensis invasion appeared to decrease the total soil CO_(2) emissions in both the field study and the greenhouse experiment.The suppressive effects on soil respiration may be attributed to S.canadensis invasion-induced alterations in the quality and quantity of available soil substrate,suggesting that S.canadensis invasion may impact soil carbon cycling via plant-released substrates and by competing for the soil available substrate with native plant and/or soil microbes.These results have substantial implications for estimations of the effects of invasive plants on belowground carbon dynamics and their contribution to the warming world.展开更多
Increasing salt-affected agricultural land due to low precipitation, high surface evaporation, irrigation with saline water, and poor cultural practices has triggered the interest to understand the influence of salt o...Increasing salt-affected agricultural land due to low precipitation, high surface evaporation, irrigation with saline water, and poor cultural practices has triggered the interest to understand the influence of salt on nitrous oxide （N20） and carbon dioxide （CO2） emissions from soil. Three soils with varying electrical conductivity of saturated paste extract （ECe） （0.44-7.20 dS m-1） and sodium adsorption ratio of saturated paste extract （SARe） （1.1-27.7）, two saline-sodic soils （S2 and S3） and a non-saline, non-sodic soil （S1）, were incubated at moisture levels of 40%, 60%, and 80% water-filled pore space （WFPS） for 30 d, with or without nitrogen （N） fertilizer addition （urea at 525μg g-1 soil）. Evolving CO2 and N20 were estimated by analyzing the collected gas samples during the incubation period. Across all moisture and N levels, the cumulative N20 emissions increased significantly by 39.8% and 42.4% in S2 and S3, respectively, compared to S1. The cumulative CO2 emission from the three soils did not differ significantly as a result of the complex interactions of salinity and sodicity. Moisture had no significant effect oi1 N20 emissions, but cumulative CO2 emissions increased significantly with an increase in moisture. Addition of N significantly increased cumulative N20 and CO2 emissions. These showed that saline-sodic soils can be a significant contributor of N20 to the environment compared to non-saline, non-sodic soils. The application of N fertilizer, irrigation, and precipitation may potentially increase greenhouse gas （N20 and CO2） releases from saline-sodic soils.展开更多
The closed-jar incubation method is widely used to estimate the mineralization of soil organic C. There are two C pools （i.e., organic and inorganic C） in calcareous soil. To evaluate the effect of additional carbon...The closed-jar incubation method is widely used to estimate the mineralization of soil organic C. There are two C pools （i.e., organic and inorganic C） in calcareous soil. To evaluate the effect of additional carbonates on CO2 emission from calcareous soil during closed-jar incubation, three incubation experiments were conducted by adding different types （CaCO3 and MgCO3） and amounts of carbonate to the soil. The addition of carbonates significantly increased CO2 emission from the soil; the increase ranged from 12.0~ in the CaCO3 amended soil to 460~0 in the MgCO3 amended soil during a 100-d incubation. Cumulative CO2 production at the end of the incubation was three times greater in the MgCO3 amended soil compared to the CaCO3 amended one. The CO2 emission increased with the amount of CaCO3 added to the soil. In contrast, CO2 emission decreased as the amount of MgCO3 added to the soil increased. Our results confirmed that the closed-jar incubation method could lead to an overestimate of organic C mineralization in calcareous soils. Because of its effect on soil pH and the dissolution of carbonates, HgC12 should not be used to sterili~.e calcareous soil if the experiment includes the measurement of soil CO2 production.展开更多
In semiarid regions of the Mediterranean basin, a rainfall event can induce a respiratory pulse that releases a large amount of soil carbon dioxide （CO2） into the atmosphere; this pulse can significantly contribute ...In semiarid regions of the Mediterranean basin, a rainfall event can induce a respiratory pulse that releases a large amount of soil carbon dioxide （CO2） into the atmosphere; this pulse can significantly contribute to the annual ecosystem carbon （C） balance. The impacts of conventional tillage and two different cover crops, resident vegetation and Bromus catharticus L., on soil CO2 effiux were evaluated in a Vitis vinifera L. vineyard in La Rioja, Spain. Soil CO2 efflux, gravimetric water content, and temperature were monitored at a depth of 0-5 cm after rainfall precipitation events approximately every 10 d in the period from May 17 to July 27, 2012, during which the cover crops had withered. Additionally, on June 10, 2012, soil organic C, microbial biomass C, and I^-glucosidase activity were determined at soil depths of 0-2.5, 2.5-5, 5-15, and 15-25 cm. The results show that pulses of soil CO2 were related to the increase in soil water content following precipitation events. Compared to the conventional tillage treatment, both cover crop treatments had higher soil CO2 efflux after precipitation events. Both cover crop treatments had higher soil organic C, microbial biomass C, and β-glucosidase activity at the soil surface （0-2.5 cm） than the conventional tillage treatment. Each pulse of CO2 was related to the surface soil properties. Thus, this study suggests that the enhancement of soil organic C and microbiological properties at the soil surface under cover crops may increase soil CO2 efflux relative to conventional tillage immediately after precipitation events during the dry season.展开更多
基金This research was supported by National Natural Science Foundation of China (Grant No. 40171092).
文摘The forest ecosystem plays an important role in the global carbon cycling. A study was conducted to evaluate soil CO2 flux and its seasonal and diurnal variation with the air and soil temperatures by using static closed chamber technique in a typical broad-leaved/Korean pine mixed forest area on the northern slope of Changbai Mountain, Jilin Province, China. The experiment was carried out through the day and night in the growing season (from June to September) in situ and sample gas was analyzed by a gas chromatograph. Results showed that the forest floor was a large net source of carbon, and soil CO2 fluxes had an obvi-ous law of seasonal and diel variation. The soil CO2 flux of broad-leaved/Korean pine mixed forest was in the range of 0.302.42 mmol穖-2穝-1 with the mean value of 0.98 mmol穖-2穝-1. An examination on the seasonal pattern of soil CO2 emission suggested that the variability in soil CO2 flux could be correlated with variations in soil temperature, and the maximum of mean CO2 flux occurred in July ((1.27±23%) mmol穖-2穝-1) and the minimum was in September ((0.50±28%) mmol穖-2穝-1). The fluctuations in diel soil CO2 flux were also correlated with changes in soil temperature; however, there existed a factor for a time lag. Soil CO2 flux from the forest floor was strongly related to soil temperature and had the highest correlation with temperature at 6-cm depth of soil. Q10 values based on air temperature and soil temperature of different soil depths were at the ranges of 2.09–3.40.
基金Supported by the Special R&D Fund for Public Welfare IndustryApplication of Remote Sensing Technology in Agrometeorological Forecast(GYHY201106027)~~
文摘[Objective] The aim was to overview the emission of greenhouse gases in farmland. [Method] Based on domestic and foreign references, production mechanism, discharging characters and major influential factors of CO2, CH4 and N2O in soils of farmland were overviewed. [Result] Production and discharge of CO2, CH. and N2O played an important role in circulation of carbon and nitrogen in terrestrial ecosystem and constituted a key method for carbon and nitrogen output. It is significant to conduct research on reduction of greenhouse gas and increase of absorption. [Conclusion] The research is beneficial for exploration on discharge rule and influential factors of greenhouse gases, providing theoretical references for reduction of greenhouse gases and study on climate change.
基金Project supported by the National Natural Science Foundation of China(No.90411020)the National Key Basic Research Program(973 Program)of China(No.2002CB412502)
文摘Soil samples were taken from an Ermans birch （Betula ermanii）-dark coniferous forest （Picea jezoensis and Abies nephrolepis） ecotone growing on volcanic ejecta in the northern slope of Changbai Mountains of Northeast China, to compare soil carbon （C） and nitrogen （N） transformations in the two forests. The soil type is Umbri-Gelic Cambosols in Chinese Soil Taxonomy. Soil samples were incubated aerobically at 20℃ and field capacity of 700 g kg^-1 over a period of 27 weeks. The amount of soil microbial biomass and net N mineralization were higher in the Ermans birch than the dark coniferous forest （P 〈 0.05）, whereas the cumulative C mineralization （as CO2 emission） in the dark coniferous forest exceeded that in the Ermans birch （P 〈 0.05）. Release of the cumulative dissolved organic C and dissolved organic N were greater in the Ermans birch than the dark coniferous forest （P 〈 0.05）. The results suggested that differences of forest types could result in considerable change in soil C and N transformations.
文摘Rice paddies are increasingly being converted to vegetable production due to economic benefits related,in part,to changes in demand during recent decades.Here,we implemented a parallel field experiment to simultaneously measure annual emissions of CH_4and N_2O,and soil organic carbon(SOC)stock changes,in rice paddies(RP),rice paddy–converted conventional vegetable fields(CV),and rice paddy–converted greenhouse vegetable fields(GV).Changing from rice to vegetable production reduced CH_4emissions by nearly 100%,and also triggered substantial N_2O emissions.Furthermore,annual N_2O emissions from GV significantly exceeded those from CV due to lower soil p H and higher soil temperature.Marginal SOC losses occurred after one year of cultivation of RP,CV,and GV,contributing an important share(3.4%,32.2%,and 10.3%,respectively)of the overall global warming potential(GWP)balance.The decline in CH_4emissions outweighed the increased N_2O emissions and SOC losses in CV and GV,leading to a 13%–30%reduction in annual GWP as compared to RP.These results suggest that large-scale expansion of vegetable production at the expense of rice paddies is beneficial for mitigating climate change in terms of the overall GWP.
文摘The recovering logged-over forest ecosystem increases the CO2 efflux into the atmospheric carbon pool in response to environmental factors to changes in the soil temperature and moisture. These CO2 outbursts can have a marked influence on the ecosystem carbon balance and thereby affect the atmospheric carbon pool. The study was conducted in the 10-year-old logged-over forest of Sungai Menyala forest, Port Dickson, Negeri Sembilan, Malaysia. The measurements of soil CO2 efflux were conducted using the continuous open flow chamber technique connected to a multi gas-handling unit and infrared CO2/H2O gas analyser. The aim of this study was to determine the soil CO2 efflux and the environmental variables and likewise the impact of environmental factors on soil CO2 efflux. Post-hoc comparisons were made using the Tukey test （p 〈 0.05）, and multiple linear regression to determine the impact of environmental factors on soil CO2 efflux. Soil CO2 efflux ranged from 100.22-553.40 mg m^-2 h^-1 with the highest efflux in the afternoon attributed to an increase in soil temperature and low moisture. A higher soil temperature and low moisture signify an influential factor as the forest is recovering from logging activity. Furthermore, the predictor environmental variables： SOC （soil organic carbon）, TOC （total organic carbon）, SMC （soil moisture content）, Bulk Density, SOCstock （soil organic carbon stock）, TAGB （total above ground carbon biomass）, Below Ground Carbon Biomass, soil pH, Nitrogen to Carbon ratio account for the spatial and temporal variation in soil CO： efflux into the atmosphere. The analysis revealed a strong correlation between soil CO2 efflux, changes soil properties and environmental factors with an R^2 more than 0.80 at p 〈 0.01. This is proven that logging activity accounts for the changes in environmental factors to influence soil CO2 efflux rate within 10-years of logging and forest recovering.
基金State Key Research Development Program of China(2017YFC1200100)the NationalNatural Science Foundation of China(31800342,31770446,32071521)+4 种基金the China Postdoctoral Science Foundation(2019M651720)the Talent Project from the Double Entrepreneurial Plan in Jiangsu Provincethe Jiangsu University Foundationthe Postgraduate Research and Practice InnovationProgram of Jiangsu Province(SJCX19.0568).
文摘Invasive alien plants not only decrease riparian vegetation diversity but also alter wetland ecosystem carbon processes,especially when they displace the original vegetation.Invasive Canada goldenrod(Solidago canadensis L.)has colonized large areas of disturbed and undisturbed land in southeastern China,yet little is known regarding how it affects soil carbon cycling.To explore the response patterns of soil respiration following S.canadensis invasion and their driving mechanisms,an observational field study and a greenhouse experiment simulating invasion were performed.In the field study,soil respiration was measured weekly from 21th July 2018 to 15th December 2018.In the greenhouse experiment,soil,autotrophic and heterotrophic respiration were measured every 1st and 15th of the month from 15th July 2019 to 15th December 2019.Soil,autotrophic and heterotrophic respiration were measured using a closed-chamber system with the deep gauze collar root exclusion method.Solidago canadensis invasion appeared to decrease the total soil CO_(2) emissions in both the field study and the greenhouse experiment.The suppressive effects on soil respiration may be attributed to S.canadensis invasion-induced alterations in the quality and quantity of available soil substrate,suggesting that S.canadensis invasion may impact soil carbon cycling via plant-released substrates and by competing for the soil available substrate with native plant and/or soil microbes.These results have substantial implications for estimations of the effects of invasive plants on belowground carbon dynamics and their contribution to the warming world.
文摘Increasing salt-affected agricultural land due to low precipitation, high surface evaporation, irrigation with saline water, and poor cultural practices has triggered the interest to understand the influence of salt on nitrous oxide （N20） and carbon dioxide （CO2） emissions from soil. Three soils with varying electrical conductivity of saturated paste extract （ECe） （0.44-7.20 dS m-1） and sodium adsorption ratio of saturated paste extract （SARe） （1.1-27.7）, two saline-sodic soils （S2 and S3） and a non-saline, non-sodic soil （S1）, were incubated at moisture levels of 40%, 60%, and 80% water-filled pore space （WFPS） for 30 d, with or without nitrogen （N） fertilizer addition （urea at 525μg g-1 soil）. Evolving CO2 and N20 were estimated by analyzing the collected gas samples during the incubation period. Across all moisture and N levels, the cumulative N20 emissions increased significantly by 39.8% and 42.4% in S2 and S3, respectively, compared to S1. The cumulative CO2 emission from the three soils did not differ significantly as a result of the complex interactions of salinity and sodicity. Moisture had no significant effect oi1 N20 emissions, but cumulative CO2 emissions increased significantly with an increase in moisture. Addition of N significantly increased cumulative N20 and CO2 emissions. These showed that saline-sodic soils can be a significant contributor of N20 to the environment compared to non-saline, non-sodic soils. The application of N fertilizer, irrigation, and precipitation may potentially increase greenhouse gas （N20 and CO2） releases from saline-sodic soils.
基金Supported by the National Natural Science Foundation of China(Nos.40571087 and 40773057)the National Key Technologies Research and Development Program of China during the 11th Five-Year Plan Period(No.2007BAD89B02)
文摘The closed-jar incubation method is widely used to estimate the mineralization of soil organic C. There are two C pools （i.e., organic and inorganic C） in calcareous soil. To evaluate the effect of additional carbonates on CO2 emission from calcareous soil during closed-jar incubation, three incubation experiments were conducted by adding different types （CaCO3 and MgCO3） and amounts of carbonate to the soil. The addition of carbonates significantly increased CO2 emission from the soil; the increase ranged from 12.0~ in the CaCO3 amended soil to 460~0 in the MgCO3 amended soil during a 100-d incubation. Cumulative CO2 production at the end of the incubation was three times greater in the MgCO3 amended soil compared to the CaCO3 amended one. The CO2 emission increased with the amount of CaCO3 added to the soil. In contrast, CO2 emission decreased as the amount of MgCO3 added to the soil increased. Our results confirmed that the closed-jar incubation method could lead to an overestimate of organic C mineralization in calcareous soils. Because of its effect on soil pH and the dissolution of carbonates, HgC12 should not be used to sterili~.e calcareous soil if the experiment includes the measurement of soil CO2 production.
基金supported by the Spanish Ministry of Science, INIA (Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria), SpainEuropean Social Fund (INIA-RTA 2009-00101-00-00)the INIA and European Social Fund for his postdoctoral grant
文摘In semiarid regions of the Mediterranean basin, a rainfall event can induce a respiratory pulse that releases a large amount of soil carbon dioxide （CO2） into the atmosphere; this pulse can significantly contribute to the annual ecosystem carbon （C） balance. The impacts of conventional tillage and two different cover crops, resident vegetation and Bromus catharticus L., on soil CO2 effiux were evaluated in a Vitis vinifera L. vineyard in La Rioja, Spain. Soil CO2 efflux, gravimetric water content, and temperature were monitored at a depth of 0-5 cm after rainfall precipitation events approximately every 10 d in the period from May 17 to July 27, 2012, during which the cover crops had withered. Additionally, on June 10, 2012, soil organic C, microbial biomass C, and I^-glucosidase activity were determined at soil depths of 0-2.5, 2.5-5, 5-15, and 15-25 cm. The results show that pulses of soil CO2 were related to the increase in soil water content following precipitation events. Compared to the conventional tillage treatment, both cover crop treatments had higher soil CO2 efflux after precipitation events. Both cover crop treatments had higher soil organic C, microbial biomass C, and β-glucosidase activity at the soil surface （0-2.5 cm） than the conventional tillage treatment. Each pulse of CO2 was related to the surface soil properties. Thus, this study suggests that the enhancement of soil organic C and microbiological properties at the soil surface under cover crops may increase soil CO2 efflux relative to conventional tillage immediately after precipitation events during the dry season.
