Heavy metal pollution in karst mountainous area of Guizhou has spread due to the long-term exploitation of mineral resources and the improper disposal of environmentally hazardous waste. Heavy metals are characterised...Heavy metal pollution in karst mountainous area of Guizhou has spread due to the long-term exploitation of mineral resources and the improper disposal of environmentally hazardous waste. Heavy metals are characterised by non-degradation, strong toxicity, and constant accumulation, posing a grave threat to karst mountain fragile soil ecosystem. To reduce the harm caused by heavy metal pollution and damage to agricultural products, research was undertaken on the basis of previous work by simulating pot experiments on pak choi cabbage(Brassica rapa chinensis)planted in Cd-contaminated soil: different amounts of organic mineral fertilisers(OMF) compared with chemical fertiliser(CF) were used and by detecting the amount of heavy metal in the mature vegetable, a better fertilisation strategy was developed. The results showed that the Cd content in vegetables grown with CF was 23.70 mg/kg,while that of vegetables grown with OMF and bacterial inoculant was the lowest at 15.13 mg/kg. This suggests that the use of OMF and microbes in karst areas not only promotes plant growth but also hinders plant absorption of heavy metal ions in the soil. In addition, through the collection of pot leachate, the detection of water chemistrycharacteristics, and the calculation of the calcite saturation index, it was found that the OMF method also induces certain carbon sink effects. The results provide a new way in which rationalise the use of OMFs in karst areas to alleviate soil heavy metal pollution and increase soil carbon sequestration.展开更多
1 Introduction Marsh-wetland,as an important type of wetlands,is a synthetic natural ecosystem with rich soil organic carbon.The largest area of marsh-wetland was located in Sanjiang Plain in the Northeast China and o...1 Introduction Marsh-wetland,as an important type of wetlands,is a synthetic natural ecosystem with rich soil organic carbon.The largest area of marsh-wetland was located in Sanjiang Plain in the Northeast China and obvious land use changes have occurred during the last 50 years with large area of marsh-wetland cultivated to farmland which had a big impact on soil organic carbon stock.In this study,spatial distributions of 0-20cm soil organic carbon sources and sinks in Sanjiang Plain were investigated from 1980 to 2016.展开更多
Fertilization and aglime(agricultural lime) application, as important agricultural activities in acid soil, exert an influence on the fluxes of carbon both between and within ecosystems. Animal manure added to soil ca...Fertilization and aglime(agricultural lime) application, as important agricultural activities in acid soil, exert an influence on the fluxes of carbon both between and within ecosystems. Animal manure added to soil can elevate the soil CO_2 and release organic acid due to microbial decomposition of the high organic matter content of animal manure. Additionally, the elevated CO_2 can accelerate carbonate weathering in alkaline soil, such as lime soil. However, in acidic soil, it is unclear whether the chemical weathering of additive aglime can be quickened by the elevated CO_2 due to animal manure addition. Thus, to ascertain the impact of animal manure addition on aglime weathering in acidic soil and to understand the weathering agent of aglime or underlying carbonate in the acidic soil profile, we established two contrasting profiles(control profile and manurial profile) in a cabbage-corn or capsicum-corn rotation in a field experiment site located in the Hua Xi district of Guiyang, China, and buried carbonate rock tablets at different depths of soil profiles to calculate the dissolution rate of carbonate rock by monitoring the weights of the tablets. The results indicated that soil CO_2 increased due to animal manure addition, but the rate of dissolution of the carbonate rock tablets was reduced, which was attributed to the increase in the p H in acidic soil after animal manure addition because the relationship between the dissolution rate of carbonate rock and soil p H indicated that the weathering rate of carbonate rock was controlled by pH and not by CO_2 in acidic soil. Thus, the contribution of H+ ions(mainly exchangeable acid) in acid soil as a weathering agent to the weathering of underlying carbonate(and/or aglime) may lead to the overestimation of the CO_2 consumption through chemical weathering at the regional/global scale using hydro-chemical methods.展开更多
目前,在区域尺度,NEP趋势变化的强度和影响机制还存在很大的不确定性.针对这一问题,我们选取了一带一路覆盖的区域为研究对象,基于全球陆面模式(CABLE)和第六次国际耦合模式比较计划(CMIP6),评估了历史和未来NEP趋势的变化,分析了影响...目前,在区域尺度,NEP趋势变化的强度和影响机制还存在很大的不确定性.针对这一问题,我们选取了一带一路覆盖的区域为研究对象,基于全球陆面模式(CABLE)和第六次国际耦合模式比较计划(CMIP6),评估了历史和未来NEP趋势的变化,分析了影响的机制.从过去到未来,CABLE结果表明NEP的趋势从0.015 Pg C yr^(-2)减少到-0.023 Pg C yr^(-2);CMIP6结果为从0.014 Pg C yr^(-2)转变为-0.009 Pg C yr^(-2).气候变化是引起这一变化的主因.我们的研究结果强调了碳-气候-氮相互作用的重要性,这对碳中和目标下碳汇潜力的准确估算尤为重要.展开更多
Mangrove soils are well known for their high capacity of storing organic carbon (SOC) in various pools;however, a relatively small change in SOC pools could cause significant impacts on greenhouse gas concentrations. ...Mangrove soils are well known for their high capacity of storing organic carbon (SOC) in various pools;however, a relatively small change in SOC pools could cause significant impacts on greenhouse gas concentrations. Thus, for an in-depth understanding of SOC distribution and stock to predict the role of Sundarbans mangrove in mitigating global warming and greenhouse effects, different extraction methods were employed to fractionate the SOC of Sundarbans soils into cold-water (CWSC) and hot-water (HWSC) soluble, moderately labile (MLF), microbial biomass carbon (MBC), and resistant fractions (RF) using a newly developed modified-method. A significant variation in total SOC (p < 0.001), SOC stock (p < 0.001) and soil bulk density (p < 0.05) at the Sundarbans mangrove forest were observed. In most soils, bulk density increased from the surface to 100 cm depth. The total SOC concentrations were higher in most surface soils and ranged from 1.21% ± 0.02% to 8.19% ± 0.09%. However, C in lower layers may be more resistant than that of upper soils because of differences in compositions, sources and environmental conditions. SOC was predominately associated with the resistant fraction (81% - 97%), followed by MLF (2% - 10%), HWSC (1% - 4%), MBC (~0% - 4%), and CWSC (~0% - 3%). The significant positive correlations between different C fractions suggested that C pools are interdependent and need proper management plans to increase these pools in Sundarbans soils. The SOC stock of the studied areas ranged between 16.75 ± 3.83 to 135.12 ± 28.61 kg·C·m<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span>2</sup> in 1 m soil profile and has an average of 31.80 kg·C·m<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span>2</sup>. The substratum soils had more carbon than the upper layers in the Sundarbans wetland due to burial and preservation of carbon by frequent tidal inundation. A higher SOC stock in the soil profile and its primary association in resistant fractions suggested that Sundarbans mangrove soil is sequestering carbon and thereby serving as a significant carbon sink in Bangladesh.展开更多
基金funded by National Natural Science Foundation of China(41373078)National Major Scientific Research Program(2013CB956702)Key Project of Natural Science Research in Colleges and Universities in Jiangsu Province(Grant No.16KJA180003)
文摘Heavy metal pollution in karst mountainous area of Guizhou has spread due to the long-term exploitation of mineral resources and the improper disposal of environmentally hazardous waste. Heavy metals are characterised by non-degradation, strong toxicity, and constant accumulation, posing a grave threat to karst mountain fragile soil ecosystem. To reduce the harm caused by heavy metal pollution and damage to agricultural products, research was undertaken on the basis of previous work by simulating pot experiments on pak choi cabbage(Brassica rapa chinensis)planted in Cd-contaminated soil: different amounts of organic mineral fertilisers(OMF) compared with chemical fertiliser(CF) were used and by detecting the amount of heavy metal in the mature vegetable, a better fertilisation strategy was developed. The results showed that the Cd content in vegetables grown with CF was 23.70 mg/kg,while that of vegetables grown with OMF and bacterial inoculant was the lowest at 15.13 mg/kg. This suggests that the use of OMF and microbes in karst areas not only promotes plant growth but also hinders plant absorption of heavy metal ions in the soil. In addition, through the collection of pot leachate, the detection of water chemistrycharacteristics, and the calculation of the calcite saturation index, it was found that the OMF method also induces certain carbon sink effects. The results provide a new way in which rationalise the use of OMFs in karst areas to alleviate soil heavy metal pollution and increase soil carbon sequestration.
基金granted by the United Nations Educational,Scientific and Cultural Organization program(IGCP665)the China basic geological Investigation Program(Grant No.DD20160316).
文摘1 Introduction Marsh-wetland,as an important type of wetlands,is a synthetic natural ecosystem with rich soil organic carbon.The largest area of marsh-wetland was located in Sanjiang Plain in the Northeast China and obvious land use changes have occurred during the last 50 years with large area of marsh-wetland cultivated to farmland which had a big impact on soil organic carbon stock.In this study,spatial distributions of 0-20cm soil organic carbon sources and sinks in Sanjiang Plain were investigated from 1980 to 2016.
基金supported by the National Basic Research Program of China (973 Program) (No.2006CB403200)the Chinese National Natural Science Foundation (No.41403107 and No.41325010)+1 种基金the Basic Science Research Fund from the Institute of Hydrogeology and Environmental Geology (Grant No.SK200906 and SK201208)the China Geological Survey Projects (No.12120113005900)
文摘Fertilization and aglime(agricultural lime) application, as important agricultural activities in acid soil, exert an influence on the fluxes of carbon both between and within ecosystems. Animal manure added to soil can elevate the soil CO_2 and release organic acid due to microbial decomposition of the high organic matter content of animal manure. Additionally, the elevated CO_2 can accelerate carbonate weathering in alkaline soil, such as lime soil. However, in acidic soil, it is unclear whether the chemical weathering of additive aglime can be quickened by the elevated CO_2 due to animal manure addition. Thus, to ascertain the impact of animal manure addition on aglime weathering in acidic soil and to understand the weathering agent of aglime or underlying carbonate in the acidic soil profile, we established two contrasting profiles(control profile and manurial profile) in a cabbage-corn or capsicum-corn rotation in a field experiment site located in the Hua Xi district of Guiyang, China, and buried carbonate rock tablets at different depths of soil profiles to calculate the dissolution rate of carbonate rock by monitoring the weights of the tablets. The results indicated that soil CO_2 increased due to animal manure addition, but the rate of dissolution of the carbonate rock tablets was reduced, which was attributed to the increase in the p H in acidic soil after animal manure addition because the relationship between the dissolution rate of carbonate rock and soil p H indicated that the weathering rate of carbonate rock was controlled by pH and not by CO_2 in acidic soil. Thus, the contribution of H+ ions(mainly exchangeable acid) in acid soil as a weathering agent to the weathering of underlying carbonate(and/or aglime) may lead to the overestimation of the CO_2 consumption through chemical weathering at the regional/global scale using hydro-chemical methods.
基金funded by the National Natural Science Foundation of China[grant numbers 41630532,41975112,42175142,and 42175013].
文摘目前,在区域尺度,NEP趋势变化的强度和影响机制还存在很大的不确定性.针对这一问题,我们选取了一带一路覆盖的区域为研究对象,基于全球陆面模式(CABLE)和第六次国际耦合模式比较计划(CMIP6),评估了历史和未来NEP趋势的变化,分析了影响的机制.从过去到未来,CABLE结果表明NEP的趋势从0.015 Pg C yr^(-2)减少到-0.023 Pg C yr^(-2);CMIP6结果为从0.014 Pg C yr^(-2)转变为-0.009 Pg C yr^(-2).气候变化是引起这一变化的主因.我们的研究结果强调了碳-气候-氮相互作用的重要性,这对碳中和目标下碳汇潜力的准确估算尤为重要.
文摘Mangrove soils are well known for their high capacity of storing organic carbon (SOC) in various pools;however, a relatively small change in SOC pools could cause significant impacts on greenhouse gas concentrations. Thus, for an in-depth understanding of SOC distribution and stock to predict the role of Sundarbans mangrove in mitigating global warming and greenhouse effects, different extraction methods were employed to fractionate the SOC of Sundarbans soils into cold-water (CWSC) and hot-water (HWSC) soluble, moderately labile (MLF), microbial biomass carbon (MBC), and resistant fractions (RF) using a newly developed modified-method. A significant variation in total SOC (p < 0.001), SOC stock (p < 0.001) and soil bulk density (p < 0.05) at the Sundarbans mangrove forest were observed. In most soils, bulk density increased from the surface to 100 cm depth. The total SOC concentrations were higher in most surface soils and ranged from 1.21% ± 0.02% to 8.19% ± 0.09%. However, C in lower layers may be more resistant than that of upper soils because of differences in compositions, sources and environmental conditions. SOC was predominately associated with the resistant fraction (81% - 97%), followed by MLF (2% - 10%), HWSC (1% - 4%), MBC (~0% - 4%), and CWSC (~0% - 3%). The significant positive correlations between different C fractions suggested that C pools are interdependent and need proper management plans to increase these pools in Sundarbans soils. The SOC stock of the studied areas ranged between 16.75 ± 3.83 to 135.12 ± 28.61 kg·C·m<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span>2</sup> in 1 m soil profile and has an average of 31.80 kg·C·m<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span>2</sup>. The substratum soils had more carbon than the upper layers in the Sundarbans wetland due to burial and preservation of carbon by frequent tidal inundation. A higher SOC stock in the soil profile and its primary association in resistant fractions suggested that Sundarbans mangrove soil is sequestering carbon and thereby serving as a significant carbon sink in Bangladesh.
