This study proposed an integrated biogeochemical modeling of nitrogen load from anthropogenic and natural sources in Japan.Firstly,the nitrogen load(NL) from different sources such as crop,livestock,industrial plant,u...This study proposed an integrated biogeochemical modeling of nitrogen load from anthropogenic and natural sources in Japan.Firstly,the nitrogen load(NL) from different sources such as crop,livestock,industrial plant,urban and rural resident was calculated by using datasets of fertilizer utilization,population distribution, land use map,and social census.Then,the nitrate leaching from soil layers in farmland,grassland and natural conditions was calculated by using a展开更多
To protect important resources under their bureau’s purview, the United States National Park Service’s (NPS) Arctic Network (ARCN) has developed a series of “vital signs” that are to be periodically monitored. One...To protect important resources under their bureau’s purview, the United States National Park Service’s (NPS) Arctic Network (ARCN) has developed a series of “vital signs” that are to be periodically monitored. One of these vital signs focuses on wet and dry deposition of atmospheric chemicals and further, the establishment of critical load (CL) values (thresholds for ecological effects based on cumulative depositional loadings) for nitrogen (N), sulfur, and metals. As part of the ARCN terrestrial monitoring programs, samples of the feather moss Hylocomium splendens are being collected and analyzed as a cost-effective means to monitor atmospheric pollutant deposition in this region. Ultimately, moss data combined with refined CL values might be used to help guide future regulation of atmospheric contaminant sources potentially impacting Arctic Alaska. But first, additional long-term studies are needed to determine patterns of contaminant deposition as measured by moss biomonitors and to quantify ecosystem responses at particular loadings/ ranges of contaminants within Arctic Alaska. Herein we briefly summarize 1) current regulatory guidance related to CL values 2) derivation of CL models for N and metals, 3) use of mosses as biomonitors of atmospheric deposition and loadings, 4) preliminary analysis of vulnerabilities and risks associated with CL estimates for N, 5) preliminary analysis of existing data for characterization of CL values for N for interior Alaska and 6) implications for managers and future research needs.展开更多
To evaluate the nitrogen pollution load in an aquifer, a water and nitrogen balance analysis was conducted over a thirty-five year period at five yearly intervals. First, we established a two-horizon model comprising ...To evaluate the nitrogen pollution load in an aquifer, a water and nitrogen balance analysis was conducted over a thirty-five year period at five yearly intervals. First, we established a two-horizon model comprising a channel/soil horizon, and an aquifer horizon, with exchange of water between the aquifer and river. The nitrogen balance was estimated from the product of nitrogen concentration and water flow obtained from the water balance analysis. The aquifer nitrogen balance results were as follows: 1) In the aquifer horizon, the total nitrogen pollution load potential (NPLP) peaked in the period 1981-1990 at 1800 t·yr-1;following this the NPLP rapidly decreased to about 600 t·yr-1 in the period 2006-2010. The largest NPLP input component of 1000 t·yr-1 in the period 1976-1990 was from farmland. Subsequently, farmland NPLP decreased to only 400 t·yr-1 between 2006 and 2010. The second largest input component, 600 t·yr-1, was effluent from wastewater treatment works (WWTWs) in the period 1986-1990;this also decreased markedly to about 100 t·yr-1 between 2006 and 2010;2) The difference between input and output in the aquifer horizon, used as an index of groundwater pollution, peaked in the period 1986-1990 at about 1200 t·yr-1. This gradually decreased to about 200 t·yr-1 by 2006-2010. 3) The temporal change in NPLP coincided with the nitrogen concentration of the rivers in the study area. In addition, nitrogen concentrations in two test wells were 1.0 mg·l-1 at a depth of 150 m and only 0.25 mg·l-1 at 50 m, suggesting gradual percolation of the nitrogen polluted water deeper in the aquifer.展开更多
With the control of point source pollution in Dianchi Lake basin, and the expansion of Kunming city, non-point source pollution has become the main source pollution of urban water environment and Dianchi Lake. To reve...With the control of point source pollution in Dianchi Lake basin, and the expansion of Kunming city, non-point source pollution has become the main source pollution of urban water environment and Dianchi Lake. To reveal the nitrogen pollution characteristics in watershed, this research selected key monitoring points and sections at Baoxiang river basin in rainy season which is the peak transported time of non-point source pollution, the nitrogen and hydrological indicators are monitored systematically. The different forms of nitrogen are analyzed, the pollution load of nitrogen are calculated and studied at cardinal sections; combined with the literature data, we compared the water nitrogen characteristics of Dianchi basin and Taihu basin, the main results are as follows:(1) In summer, water nitrogen form of Baoxiang river in the Caohe area is dominated by nitrate nitrogen, while in other areas it is dominated by ammonia nitrogen which is accounted for 31%-50% of total nitrogen;(2) The water pollution loads of Baoxiang river tended to increase from upstream to downstream, from June to August the total nitrogen pollution mainly comes from urban areas and the pollution load is 166.408 t;(3) In Dianchi Lake watershed and Taihu Lake watershed nitrogen concentration of inflow river is higher than that of the lake, nitrate nitrogen concentration between inflow river and lake shows a little difference, while ammonia nitrogen concentration of inflow river is higher than that of the lake. The results can provide the theoretical basis for nonpoint source pollution control and urban water environment planning and improvement in Dianchi Lake Basin.展开更多
选择闽江河口短叶茳芏(Cyperus malaccensis)湿地为研究对象,基于野外氮负荷增强模拟实验,探讨了不同氮负荷水平下(NNT对照处理,0 g N m^(-2)a^(-1);LNT低氮处理,12.5 g N m^(-2)a^(-1);MNT中氮处理,25.0 g N m^(-2)a^(-1);HNT高氮处理,...选择闽江河口短叶茳芏(Cyperus malaccensis)湿地为研究对象,基于野外氮负荷增强模拟实验,探讨了不同氮负荷水平下(NNT对照处理,0 g N m^(-2)a^(-1);LNT低氮处理,12.5 g N m^(-2)a^(-1);MNT中氮处理,25.0 g N m^(-2)a^(-1);HNT高氮处理,75.0 g N m^(-2)a^(-1))湿地植物-土壤系统的氮累积与分配特征。结果表明,不同氮负荷处理下湿地土壤(TN)、NH+4-N和NO-3-N含量均发生了明显改变。相较于NNT,LNT和MNT的TN、NH+4-N和NO-3-N含量均明显增加,增幅分别为9.44%、3.57%、11.99%(LNT)和6.71%、9.37%、46.50%(MNT)。与之不同,HNT的TN含量相比NNT增幅不大,而其NH+4-N、NO-3-N含量均显著降低,降幅分别为9.26%和40.77%。不同氮负荷处理下土壤氮含量的垂直分布特征亦发生了明显变化。除HNT外,LNT和MNT的TN、NH+4-N和NO-3-N含量均以表层土壤最高。不同氮负荷处理下的TN和NH+4-N含量分布主要受SOM的影响,而NO-3-N含量分布主要受植物吸收和垂直淋失的影响。氮负荷增强条件下植物不同器官的TN含量整体表现为叶>茎>根。不同氮负荷处理下植物-土壤系统的氮储量整体以LNT和MNT较高,而HNT最低。研究发现,短叶茳芏在中低氮负荷条件下可能将更多的氮优先分配给根系,进而以拓展地下空间和提高地下生物量的方式来适应环境;而在高氮负荷条件下,其可能通过增强“自疏效应”,并通过拓展地上空间的方式来适应环境。展开更多
This study of Mikasa City in 2001, which analyzed N flow between N production and N load in seven agricultural and settlement subsystems, i.e., paddy, onion, wheat, vegetable, dairy, chicken, and citizen subsystems, a...This study of Mikasa City in 2001, which analyzed N flow between N production and N load in seven agricultural and settlement subsystems, i.e., paddy, onion, wheat, vegetable, dairy, chicken, and citizen subsystems, aimed to compare N flow in each subsystem, to determine the main sources of the N load, and to evaluate the influence of agricultural production and food consumption on N cycling in a rural area. The results showed that in Mikasa city, 38.5% of the N load came from point sources and the remainder from non-point sources with intensive vegetable farming imparting a serious N load. Because of the internal N cycling in the dairy subsystem, chemical fertilizer application was reduced by 70.2%, and 23.72 Mg manure N was recycled to the field; therefore, the N utilization efficiency was raised from 18.1% to 35.1%. If all the manure N in the chicken subsystem was recycled, chemical fertilizer application would be reduced by 8.1% from the present level, and the point sources of N pollution would be reduced by 20.8%.展开更多
文摘This study proposed an integrated biogeochemical modeling of nitrogen load from anthropogenic and natural sources in Japan.Firstly,the nitrogen load(NL) from different sources such as crop,livestock,industrial plant,urban and rural resident was calculated by using datasets of fertilizer utilization,population distribution, land use map,and social census.Then,the nitrate leaching from soil layers in farmland,grassland and natural conditions was calculated by using a
文摘To protect important resources under their bureau’s purview, the United States National Park Service’s (NPS) Arctic Network (ARCN) has developed a series of “vital signs” that are to be periodically monitored. One of these vital signs focuses on wet and dry deposition of atmospheric chemicals and further, the establishment of critical load (CL) values (thresholds for ecological effects based on cumulative depositional loadings) for nitrogen (N), sulfur, and metals. As part of the ARCN terrestrial monitoring programs, samples of the feather moss Hylocomium splendens are being collected and analyzed as a cost-effective means to monitor atmospheric pollutant deposition in this region. Ultimately, moss data combined with refined CL values might be used to help guide future regulation of atmospheric contaminant sources potentially impacting Arctic Alaska. But first, additional long-term studies are needed to determine patterns of contaminant deposition as measured by moss biomonitors and to quantify ecosystem responses at particular loadings/ ranges of contaminants within Arctic Alaska. Herein we briefly summarize 1) current regulatory guidance related to CL values 2) derivation of CL models for N and metals, 3) use of mosses as biomonitors of atmospheric deposition and loadings, 4) preliminary analysis of vulnerabilities and risks associated with CL estimates for N, 5) preliminary analysis of existing data for characterization of CL values for N for interior Alaska and 6) implications for managers and future research needs.
文摘To evaluate the nitrogen pollution load in an aquifer, a water and nitrogen balance analysis was conducted over a thirty-five year period at five yearly intervals. First, we established a two-horizon model comprising a channel/soil horizon, and an aquifer horizon, with exchange of water between the aquifer and river. The nitrogen balance was estimated from the product of nitrogen concentration and water flow obtained from the water balance analysis. The aquifer nitrogen balance results were as follows: 1) In the aquifer horizon, the total nitrogen pollution load potential (NPLP) peaked in the period 1981-1990 at 1800 t·yr-1;following this the NPLP rapidly decreased to about 600 t·yr-1 in the period 2006-2010. The largest NPLP input component of 1000 t·yr-1 in the period 1976-1990 was from farmland. Subsequently, farmland NPLP decreased to only 400 t·yr-1 between 2006 and 2010. The second largest input component, 600 t·yr-1, was effluent from wastewater treatment works (WWTWs) in the period 1986-1990;this also decreased markedly to about 100 t·yr-1 between 2006 and 2010;2) The difference between input and output in the aquifer horizon, used as an index of groundwater pollution, peaked in the period 1986-1990 at about 1200 t·yr-1. This gradually decreased to about 200 t·yr-1 by 2006-2010. 3) The temporal change in NPLP coincided with the nitrogen concentration of the rivers in the study area. In addition, nitrogen concentrations in two test wells were 1.0 mg·l-1 at a depth of 150 m and only 0.25 mg·l-1 at 50 m, suggesting gradual percolation of the nitrogen polluted water deeper in the aquifer.
基金supported by the 2015 Science and Technology Project of Yunnan Province (Grant No. 2015FD075)Yunnan Normal University Scientific Research Training Fund Project (Grant No. ky2015-141)
文摘With the control of point source pollution in Dianchi Lake basin, and the expansion of Kunming city, non-point source pollution has become the main source pollution of urban water environment and Dianchi Lake. To reveal the nitrogen pollution characteristics in watershed, this research selected key monitoring points and sections at Baoxiang river basin in rainy season which is the peak transported time of non-point source pollution, the nitrogen and hydrological indicators are monitored systematically. The different forms of nitrogen are analyzed, the pollution load of nitrogen are calculated and studied at cardinal sections; combined with the literature data, we compared the water nitrogen characteristics of Dianchi basin and Taihu basin, the main results are as follows:(1) In summer, water nitrogen form of Baoxiang river in the Caohe area is dominated by nitrate nitrogen, while in other areas it is dominated by ammonia nitrogen which is accounted for 31%-50% of total nitrogen;(2) The water pollution loads of Baoxiang river tended to increase from upstream to downstream, from June to August the total nitrogen pollution mainly comes from urban areas and the pollution load is 166.408 t;(3) In Dianchi Lake watershed and Taihu Lake watershed nitrogen concentration of inflow river is higher than that of the lake, nitrate nitrogen concentration between inflow river and lake shows a little difference, while ammonia nitrogen concentration of inflow river is higher than that of the lake. The results can provide the theoretical basis for nonpoint source pollution control and urban water environment planning and improvement in Dianchi Lake Basin.
文摘选择闽江河口短叶茳芏(Cyperus malaccensis)湿地为研究对象,基于野外氮负荷增强模拟实验,探讨了不同氮负荷水平下(NNT对照处理,0 g N m^(-2)a^(-1);LNT低氮处理,12.5 g N m^(-2)a^(-1);MNT中氮处理,25.0 g N m^(-2)a^(-1);HNT高氮处理,75.0 g N m^(-2)a^(-1))湿地植物-土壤系统的氮累积与分配特征。结果表明,不同氮负荷处理下湿地土壤(TN)、NH+4-N和NO-3-N含量均发生了明显改变。相较于NNT,LNT和MNT的TN、NH+4-N和NO-3-N含量均明显增加,增幅分别为9.44%、3.57%、11.99%(LNT)和6.71%、9.37%、46.50%(MNT)。与之不同,HNT的TN含量相比NNT增幅不大,而其NH+4-N、NO-3-N含量均显著降低,降幅分别为9.26%和40.77%。不同氮负荷处理下土壤氮含量的垂直分布特征亦发生了明显变化。除HNT外,LNT和MNT的TN、NH+4-N和NO-3-N含量均以表层土壤最高。不同氮负荷处理下的TN和NH+4-N含量分布主要受SOM的影响,而NO-3-N含量分布主要受植物吸收和垂直淋失的影响。氮负荷增强条件下植物不同器官的TN含量整体表现为叶>茎>根。不同氮负荷处理下植物-土壤系统的氮储量整体以LNT和MNT较高,而HNT最低。研究发现,短叶茳芏在中低氮负荷条件下可能将更多的氮优先分配给根系,进而以拓展地下空间和提高地下生物量的方式来适应环境;而在高氮负荷条件下,其可能通过增强“自疏效应”,并通过拓展地上空间的方式来适应环境。
基金Project supported by the Science Research Foundation, Japan (No. 11460028).
文摘This study of Mikasa City in 2001, which analyzed N flow between N production and N load in seven agricultural and settlement subsystems, i.e., paddy, onion, wheat, vegetable, dairy, chicken, and citizen subsystems, aimed to compare N flow in each subsystem, to determine the main sources of the N load, and to evaluate the influence of agricultural production and food consumption on N cycling in a rural area. The results showed that in Mikasa city, 38.5% of the N load came from point sources and the remainder from non-point sources with intensive vegetable farming imparting a serious N load. Because of the internal N cycling in the dairy subsystem, chemical fertilizer application was reduced by 70.2%, and 23.72 Mg manure N was recycled to the field; therefore, the N utilization efficiency was raised from 18.1% to 35.1%. If all the manure N in the chicken subsystem was recycled, chemical fertilizer application would be reduced by 8.1% from the present level, and the point sources of N pollution would be reduced by 20.8%.
