Miyun Reservoir is the most important water source to Beijing City. Land-use of the basin plays a great role in the protection of water resources. Hence a sustainable land-use planning is required to optimize land-use...Miyun Reservoir is the most important water source to Beijing City. Land-use of the basin plays a great role in the protection of water resources. Hence a sustainable land-use planning is required to optimize land-use structure and protect water resources in the basin. Based on the complete land-use system analysis in Miyun, a grey multi-objective programming to basin land-use(GMOPBLU) model was developed and applied to land-use planning. Two alternatives were produced and analyzed by means of interactive adjustment and scenario analysis. The results showed the GMOPBLU model is a valuable approach for basin land-use planning.展开更多
The Miyun area of Beijing is located in the northern part of the North China Craton （NCC） and includes a variety of Archean granitoids and metamorphic rocks. Magmatic domains in zircon from a tonalite reveal Early N...The Miyun area of Beijing is located in the northern part of the North China Craton （NCC） and includes a variety of Archean granitoids and metamorphic rocks. Magmatic domains in zircon from a tonalite reveal Early Neoarchean （2752±7 Ma） ages show a small range in εHf（t） from 3.1 to 7.4 and tDM1（Hf） from 2742 to 2823 Ma, similar to their U-Pb ages, indicating derivation from a depleted mantle source only a short time prior to crystallization. SHRIMP zircon ages of granite, gneiss, amphibolite and hornblendite in the Miyun area reveal restricted emplacement ages from 2594 to 2496 Ma. They also record metamorphic events at ca. 2.50 Ga, 2.44 Ga and 1.82 Ga, showing a similar evolutionary history to the widely distributed Late Neoarchean rocks in the NCC. Positive eHf（t） values of 1.5 to 5.9, with model ages younger than 3.0 Ga for magmatic zircon domains from these Late Neoarchean intrusive rocks indicate that they are predominantly derived from juvenile crustal sources and suggest that significant crustal growth occurred in the northern NCC during the Neoarchean. Late Paleoproterozoic metamorphism developed widely in the NCC, not only in the Trans-North China Orogen, but also in areas of Eastern and Western Blocks, which suggest that the late Paleoproterozoic was the assembly of different micro-continents, which resulted in the final consolidation to form the NCC, and related to the development of the Paleo-Mesoproterozoic Columbia or Nuna supercontinent.展开更多
The Revised Universal Soil Loss Equation （RUSLE） was applied to assess the spatial distribution and dynamic properties of soil loss with geographic information system （GIS） and remote sensing （RS） technologies. ...The Revised Universal Soil Loss Equation （RUSLE） was applied to assess the spatial distribution and dynamic properties of soil loss with geographic information system （GIS） and remote sensing （RS） technologies. To improve the accuracy of soil-erosion estimates, a new C-factor estimation model was developed based on land cover and time series normalized difference vegetation index （NDVI） datasets. The new C-factor was then applied in the RUSLE to integrate rainfall, soil, vegetation, and topography data of different periods, and thus monitor the distribution of soil erosion patterns and their dynamics during a 3o-year period of the upstream watershed of Miynn Reservoir （UWMR）, China. The results showed that the new C-factor estimation method, which considers land cover status and dynamics, and explicitly incorporates within-land cover variability, was more rational, quantitative, and reliable. An average annual soil loss in UWMR of 25.68, 21.04, and 16.8o t ha-1 a-1 was estimated for 1990, 2000 and 2010, respectively, corroborated by comparing spatial and temporal variation in sediment yield. Between 2000 and 2010, a 1.38% average annual increase was observed in the area of lands that lost less than 5 t ha-1 a^-1, while during 1990-2000 such lands only increased on average by o.46%. Areas that classified as severe, very severe and extremely severe accounted for 5.68% of the total UWMR in 2010, and primarily occurred in dry areas or grasslands of sloping fields. The reason for the change in rate of soil loss is explained by an increased appreciation of soil conservation by developers and planners. Moreover,we recommend that UWMR watershed adopt further conservation measures such as terraced plowing of dry land, afforestation, or grassland enclosures as part of a concerted effort to reduce on-going soil erosion.展开更多
A high quality database is the starting point for any GIS application. For the Miyun Reservoir, a large amount of spatial data has been accumulated by numerous studies. This paper introduces a GIS database developme...A high quality database is the starting point for any GIS application. For the Miyun Reservoir, a large amount of spatial data has been accumulated by numerous studies. This paper introduces a GIS database development in support of these studies. And some applications of the GIS database, include integration with GPS, view and management of data, and integration with WASP5 model, are also introduced.展开更多
Miyun Reservoir was designated as the water source of Beijing City in 1982. Since that time, socio economic development in Miyun Area has been slowing due to the restriction of severe environmental standards. More and...Miyun Reservoir was designated as the water source of Beijing City in 1982. Since that time, socio economic development in Miyun Area has been slowing due to the restriction of severe environmental standards. More and more attention from the public and government has been paid to the regional sustainable development. And an effective planning for the local society management system is urgently desired. In this study, a regional sustainable development system dynamics model, named MiyunSD, is developed for supporting this planning task. MiyunSD consists of dynamic simulation models that explicitly consider information feedback that governs interactions in the system. Such models are capable of simulating the system′s behavior and predicting its developing situation of the future. For the study case, interactions among a number of system components within a time frame of fifteen years are examined dynamically. Three planning alternatives are carefully considered. The base run is based on an assumption that the existing pattern of human activities will prevail in the entire planning horizon, and the other alternatives are based on previous and present planning studies. The different alternatives will get different system′s environmental and socio economic results. Through analyzing these dynamic results, local authorities may find an optimal way to realize the objectives that the regional environment will be well protected and at the same time the economy will be rapidly developed.展开更多
Based on a high-resolution regional climate model (RegCM3) simulation over East Asia, future climate changes over the Miyun Reservoir in the 21st century under the Intergovernmental Panel on Climate Change (IPCC) Spec...Based on a high-resolution regional climate model (RegCM3) simulation over East Asia, future climate changes over the Miyun Reservoir in the 21st century under the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenarios (SRES) A1B scenario are analyzed. The model simulation extends from 1951 to 2100 at a grid spacing of 25 km and is one-way nested within a global model of MIROC3.2_ hires (the Model for Interdisciplinary Research on Climate). The focus of the analysis is on the Watershed of Miyun Reservoir, the main water supply for Beijing in northern China. The results show that RegCM3 reproduces the observed temperature well but it overestimates precipitation over the region. Significant warming in the 21st century is simulated in the annual mean, December-January-February (DJF) and June-July-August (JJA), although with differences concerning the spatial distribution and magnitude. Changes in precipitation for the annual mean, DJF, and JJA also show differences. A prevailing increase of precipitation in DJF and a decrease of it in JJA is projected over the region, while little change in the annual mean is projected. Changes of the difference between precipitation and evapotranspiration to measure the potential water availability are also presented in the paper.展开更多
The paper provides a systematical analysis of ecological restoration effects of natural secondary forest of closure area in Chao Guanxi Gou, Miyun County, Beijing. The results indicate that through more than twenty ye...The paper provides a systematical analysis of ecological restoration effects of natural secondary forest of closure area in Chao Guanxi Gou, Miyun County, Beijing. The results indicate that through more than twenty years of hillclosing afforestation since 1983, canopy closure has improved almost by 0.2; forest cover rate has raised from 7.2% to 93.8%; biodiversity, tree biomass and vegetation community have increased to a great extent. Compared with the average canopy closure before hillclosing afforestation in this area, it has improved to over 0.4 in average and increased by 0.10.2. The forest coverage degree has reached more than 90%. Consequently, the forest plays more important roles in intercepting precipitation, improving water storage capacity of soil, decreasing the surface runoff, and preventing soil and water loss.展开更多
Miyun County,located in the northeast of Chinese capital Beijing,was underwent remarkable variations in land use in recent years.This paper aimed to detect changes in land use of Miyun from 1997 to 2005,and to qualify...Miyun County,located in the northeast of Chinese capital Beijing,was underwent remarkable variations in land use in recent years.This paper aimed to detect changes in land use of Miyun from 1997 to 2005,and to qualify the response of ecosystem to LUCC based on ecosystem services valuation.With two-periods TM images,we got land use change data,and then ecosystem services values were calculated using ecosystem services valuation coefficients proposed by Chinese scholar Xie Gaodi.Results showed that water area,farm land and unused land decreased while residential land,forest land,grassland and orchard land increased during the study period.The loss of ESV was RMB 206 million and the main reason was the decrease of water area and farm land area.As for spatial variation,there were most dramatically land use change and ESV decline in reservoir ecological protection region.The coefficient sensitivity analysis indicates that valuation coefficients used in the study are suitable and results are reasonable.The driving forces of ESV loss were rapid population growth and economic development.More work should be done to make eco-environment stay healthy.展开更多
Ecological conservation area,as the main water source and ecological barrier of a city,provides ecosystem service for urban sustainable development.Land use simulation and forecast could be beneficial to improve futur...Ecological conservation area,as the main water source and ecological barrier of a city,provides ecosystem service for urban sustainable development.Land use simulation and forecast could be beneficial to improve future land use efficiency and environmental protection.In this paper,we took the Miyun district as the study area and applied the CLUE-S model for land use simulation,based on land use data in 2001 and 2010.Eight key driving factors were selected,including elevation,slope,distance,population density and others.Based on the adjusted model parameters,the land use patterns of 2020 in Miyun district were simulated respectively for rapid growth scenario,land use planning scenario and ecological protection scenario and then identify the area needed extraordinary supervision in land planning implementation.The results showed that the simulation accuracy for 2010 reached 85%considerably,implying that the CLUE-S model is well fitted for modeling the land use pattern in Miyun district.Construction land increases and cultivated land decreases dramatically by 2020 in rapid growth and land use planning scenarios.The potential land use change tends to occur near Miyun reservoir,while the sensitive area for ecological protection and land planning implementation are distributed around urban area,Fengjiayu and Jugezhuang town.Some opencast mine areas,which would be converted to forest land in planning,will be hard to execute in the actual situation,so these areas should be paid more attention in land management.The conclusions made in this study will provide data reference and basic information for the future ecological protection and land use planning implementation in Miyun district,which could also be useful for other similar cities.展开更多
AT the end of 2010, Miyun County, on the northeastern skirts of Beijing, launched a holiday promotion "Happy Warm Journey to Minyun," beckoning merrymakers to join the locals for the Chinese New Year.
Nitrogen and phosphorus are the major nutrients to cause eutrophication to degrade water quality of the Miyun Reservoir, a very important drinking water source of Beijing, China, and they are mainly from non-point sou...Nitrogen and phosphorus are the major nutrients to cause eutrophication to degrade water quality of the Miyun Reservoir, a very important drinking water source of Beijing, China, and they are mainly from non-point sources. The watershed in Miyun County was selected as the study region with a total area of 1400 km\+2. Four typical monitoring catchments and two experimental units were used to monitor the precipitation, runoff, sediment yield and pollutant loading related to various land uses in the meantime. The results show that the total nutrient loss amounts of TN and TP are \{898.07\} t/a, and \{40.70\} t/a, respectively, in which nutrients N and P carried by runoff are \{91.3%\} and \{77.3%\}, respectively. There is relatively heavier soil erosion in the northern mountain area whereas the main nutrient loss occurs near the northeast edge of the reservoir. Different land uses would influence the loss amounts of non-point source pollutants. The amount of nutrient loss from the agricultural land per unit is highest, that from forestry comes next and that from grassland is lowest. However, due to the variability of land use areas, agricultural land contributes a lot to TP and forestry lands to TN.展开更多
In the Shixia small watershed, twenty experimental plots and two monitoring channels, the residential area and livestock areas were used to monitor the flow, runoff and erosion. Nitrogen and phosphorous concentrations...In the Shixia small watershed, twenty experimental plots and two monitoring channels, the residential area and livestock areas were used to monitor the flow, runoff and erosion. Nitrogen and phosphorous concentrations associated with various land uses were analyzed at the same time. The results are presented as follows: (1) TP, TN and COD concentrations of runoff samples in the residential area and livestock areas are nearly 10 times those in other land-use areas. High nutrient loads are associated with village land use, which is due to unsuitable livestock rising. These areas should be treated as the critical areas of non-point source pollution. (2) Different land-use influences intensity the loss of nutrients, especially slope tillings in agricultural land. The amount of nutrient loss from agricultural land per unit is highest, that from forestry is intermediate and that from pastures is lowest. However, in consideration of the variability of land-use areas, agricultural land contributes the greatest to TP and forestry land to TN. (3) The concentrations of TN and TP in sediments from gangues are highest, those in forestry land are intermediate, and those in agricultural land are lowest. Nutrient loss from hilly areas is much greater than from mountainous areas.展开更多
Creative agriculture,a new agricultural format formed by integrating agriculture,tourism and creative industries,is an important part of the urban modern agriculture. Proceeding from the functional position as an ecol...Creative agriculture,a new agricultural format formed by integrating agriculture,tourism and creative industries,is an important part of the urban modern agriculture. Proceeding from the functional position as an ecological conservation area,Miyun creative agriculture has obtained rapid growth,relying on its ecological resources,agricultural resources,tourist resources and leisure industry advantages. But there are still some problems. On the basis of analyzing the advantages and problems of creative agriculture in Miyun,the paper put forward the basic principles and thought pattern of developing creative agriculture in there. Besides,several countermeasures in terms of resources integration, scientific planning,exploring local cultural resources,developing theme products,constructing industrial chain,carrying out project design and creative planning,creating creative agricultural advantage brand are put forward.展开更多
为准确揭示密云水库流域径流变化的物理成因,基于降水、径流非平稳特征诊断结果,采用SWAT(soil and water assessment tool)水文模型,基于Budyko理论的弹性系数法和水量平衡法揭示该流域径流变化原因;对比验证各模型归因结果差异,进一...为准确揭示密云水库流域径流变化的物理成因,基于降水、径流非平稳特征诊断结果,采用SWAT(soil and water assessment tool)水文模型,基于Budyko理论的弹性系数法和水量平衡法揭示该流域径流变化原因;对比验证各模型归因结果差异,进一步探究归因方法和基准期选择对流域径流变化归因结果的影响。结果表明:基于Budyko理论的水量平衡方法更适用于水利工程众多、跨流域调水活动频繁的密云水库流域径流变化归因计算;利用该方法进行分析,当基准期长度达到16年及以上时,流域径流变化归因分析结果逐渐趋于稳定,而基准期选取过短会高估人类活动对径流的减水效应;此外,基准期选取靠近研究初始时段时,计算得到人类活动的减水效应相对较大。综合考虑上述各因素的影响,认为人类活动是密云水库流域径流变化的主导因素;在变化期Ⅰ,其减水效应在-128.32%~-119.56%波动,在变化期Ⅱ,其对径流的削减作用为-75.58%~-70.70%。研究结果有助于提升对密云水库流域径流复杂演变规律和物理成因的科学认识。展开更多
文摘Miyun Reservoir is the most important water source to Beijing City. Land-use of the basin plays a great role in the protection of water resources. Hence a sustainable land-use planning is required to optimize land-use structure and protect water resources in the basin. Based on the complete land-use system analysis in Miyun, a grey multi-objective programming to basin land-use(GMOPBLU) model was developed and applied to land-use planning. Two alternatives were produced and analyzed by means of interactive adjustment and scenario analysis. The results showed the GMOPBLU model is a valuable approach for basin land-use planning.
基金financially supported by the National Natural Science Foundation of China(grants No.41173065 and 40703012)the China Geological Survey(grants No.1212011121075, 12120114020901,12120113094000 and 1212011120332)the Basic Outlay of Scientific Research Work from the Ministry of Science and Technology of the People's Republic of China(grant No.J1403)
文摘The Miyun area of Beijing is located in the northern part of the North China Craton （NCC） and includes a variety of Archean granitoids and metamorphic rocks. Magmatic domains in zircon from a tonalite reveal Early Neoarchean （2752±7 Ma） ages show a small range in εHf（t） from 3.1 to 7.4 and tDM1（Hf） from 2742 to 2823 Ma, similar to their U-Pb ages, indicating derivation from a depleted mantle source only a short time prior to crystallization. SHRIMP zircon ages of granite, gneiss, amphibolite and hornblendite in the Miyun area reveal restricted emplacement ages from 2594 to 2496 Ma. They also record metamorphic events at ca. 2.50 Ga, 2.44 Ga and 1.82 Ga, showing a similar evolutionary history to the widely distributed Late Neoarchean rocks in the NCC. Positive eHf（t） values of 1.5 to 5.9, with model ages younger than 3.0 Ga for magmatic zircon domains from these Late Neoarchean intrusive rocks indicate that they are predominantly derived from juvenile crustal sources and suggest that significant crustal growth occurred in the northern NCC during the Neoarchean. Late Paleoproterozoic metamorphism developed widely in the NCC, not only in the Trans-North China Orogen, but also in areas of Eastern and Western Blocks, which suggest that the late Paleoproterozoic was the assembly of different micro-continents, which resulted in the final consolidation to form the NCC, and related to the development of the Paleo-Mesoproterozoic Columbia or Nuna supercontinent.
基金supported by the National Natural Science Foundation of China (Grant No.41101399)the open fund of State Key Laboratory of Remote Sensing ScienceJointly Sponsored by the Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University,China
文摘The Revised Universal Soil Loss Equation （RUSLE） was applied to assess the spatial distribution and dynamic properties of soil loss with geographic information system （GIS） and remote sensing （RS） technologies. To improve the accuracy of soil-erosion estimates, a new C-factor estimation model was developed based on land cover and time series normalized difference vegetation index （NDVI） datasets. The new C-factor was then applied in the RUSLE to integrate rainfall, soil, vegetation, and topography data of different periods, and thus monitor the distribution of soil erosion patterns and their dynamics during a 3o-year period of the upstream watershed of Miynn Reservoir （UWMR）, China. The results showed that the new C-factor estimation method, which considers land cover status and dynamics, and explicitly incorporates within-land cover variability, was more rational, quantitative, and reliable. An average annual soil loss in UWMR of 25.68, 21.04, and 16.8o t ha-1 a-1 was estimated for 1990, 2000 and 2010, respectively, corroborated by comparing spatial and temporal variation in sediment yield. Between 2000 and 2010, a 1.38% average annual increase was observed in the area of lands that lost less than 5 t ha-1 a^-1, while during 1990-2000 such lands only increased on average by o.46%. Areas that classified as severe, very severe and extremely severe accounted for 5.68% of the total UWMR in 2010, and primarily occurred in dry areas or grasslands of sloping fields. The reason for the change in rate of soil loss is explained by an increased appreciation of soil conservation by developers and planners. Moreover,we recommend that UWMR watershed adopt further conservation measures such as terraced plowing of dry land, afforestation, or grassland enclosures as part of a concerted effort to reduce on-going soil erosion.
文摘A high quality database is the starting point for any GIS application. For the Miyun Reservoir, a large amount of spatial data has been accumulated by numerous studies. This paper introduces a GIS database development in support of these studies. And some applications of the GIS database, include integration with GPS, view and management of data, and integration with WASP5 model, are also introduced.
文摘Miyun Reservoir was designated as the water source of Beijing City in 1982. Since that time, socio economic development in Miyun Area has been slowing due to the restriction of severe environmental standards. More and more attention from the public and government has been paid to the regional sustainable development. And an effective planning for the local society management system is urgently desired. In this study, a regional sustainable development system dynamics model, named MiyunSD, is developed for supporting this planning task. MiyunSD consists of dynamic simulation models that explicitly consider information feedback that governs interactions in the system. Such models are capable of simulating the system′s behavior and predicting its developing situation of the future. For the study case, interactions among a number of system components within a time frame of fifteen years are examined dynamically. Three planning alternatives are carefully considered. The base run is based on an assumption that the existing pattern of human activities will prevail in the entire planning horizon, and the other alternatives are based on previous and present planning studies. The different alternatives will get different system′s environmental and socio economic results. Through analyzing these dynamic results, local authorities may find an optimal way to realize the objectives that the regional environment will be well protected and at the same time the economy will be rapidly developed.
基金supported by the National Natural Science Foundation of China under Grant 40975041the National Basic Research Program of China under Grant 2009CB421407
文摘Based on a high-resolution regional climate model (RegCM3) simulation over East Asia, future climate changes over the Miyun Reservoir in the 21st century under the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenarios (SRES) A1B scenario are analyzed. The model simulation extends from 1951 to 2100 at a grid spacing of 25 km and is one-way nested within a global model of MIROC3.2_ hires (the Model for Interdisciplinary Research on Climate). The focus of the analysis is on the Watershed of Miyun Reservoir, the main water supply for Beijing in northern China. The results show that RegCM3 reproduces the observed temperature well but it overestimates precipitation over the region. Significant warming in the 21st century is simulated in the annual mean, December-January-February (DJF) and June-July-August (JJA), although with differences concerning the spatial distribution and magnitude. Changes in precipitation for the annual mean, DJF, and JJA also show differences. A prevailing increase of precipitation in DJF and a decrease of it in JJA is projected over the region, while little change in the annual mean is projected. Changes of the difference between precipitation and evapotranspiration to measure the potential water availability are also presented in the paper.
基金Supported by Tenth Five-Year Plan National Key Projects in Science and Technology (Grant No.2001BA510B02-02)
文摘The paper provides a systematical analysis of ecological restoration effects of natural secondary forest of closure area in Chao Guanxi Gou, Miyun County, Beijing. The results indicate that through more than twenty years of hillclosing afforestation since 1983, canopy closure has improved almost by 0.2; forest cover rate has raised from 7.2% to 93.8%; biodiversity, tree biomass and vegetation community have increased to a great extent. Compared with the average canopy closure before hillclosing afforestation in this area, it has improved to over 0.4 in average and increased by 0.10.2. The forest coverage degree has reached more than 90%. Consequently, the forest plays more important roles in intercepting precipitation, improving water storage capacity of soil, decreasing the surface runoff, and preventing soil and water loss.
基金supported by the Hi-tech Research and Development Program of China(Grant No.2006AA120108)
文摘Miyun County,located in the northeast of Chinese capital Beijing,was underwent remarkable variations in land use in recent years.This paper aimed to detect changes in land use of Miyun from 1997 to 2005,and to qualify the response of ecosystem to LUCC based on ecosystem services valuation.With two-periods TM images,we got land use change data,and then ecosystem services values were calculated using ecosystem services valuation coefficients proposed by Chinese scholar Xie Gaodi.Results showed that water area,farm land and unused land decreased while residential land,forest land,grassland and orchard land increased during the study period.The loss of ESV was RMB 206 million and the main reason was the decrease of water area and farm land area.As for spatial variation,there were most dramatically land use change and ESV decline in reservoir ecological protection region.The coefficient sensitivity analysis indicates that valuation coefficients used in the study are suitable and results are reasonable.The driving forces of ESV loss were rapid population growth and economic development.More work should be done to make eco-environment stay healthy.
文摘Ecological conservation area,as the main water source and ecological barrier of a city,provides ecosystem service for urban sustainable development.Land use simulation and forecast could be beneficial to improve future land use efficiency and environmental protection.In this paper,we took the Miyun district as the study area and applied the CLUE-S model for land use simulation,based on land use data in 2001 and 2010.Eight key driving factors were selected,including elevation,slope,distance,population density and others.Based on the adjusted model parameters,the land use patterns of 2020 in Miyun district were simulated respectively for rapid growth scenario,land use planning scenario and ecological protection scenario and then identify the area needed extraordinary supervision in land planning implementation.The results showed that the simulation accuracy for 2010 reached 85%considerably,implying that the CLUE-S model is well fitted for modeling the land use pattern in Miyun district.Construction land increases and cultivated land decreases dramatically by 2020 in rapid growth and land use planning scenarios.The potential land use change tends to occur near Miyun reservoir,while the sensitive area for ecological protection and land planning implementation are distributed around urban area,Fengjiayu and Jugezhuang town.Some opencast mine areas,which would be converted to forest land in planning,will be hard to execute in the actual situation,so these areas should be paid more attention in land management.The conclusions made in this study will provide data reference and basic information for the future ecological protection and land use planning implementation in Miyun district,which could also be useful for other similar cities.
文摘AT the end of 2010, Miyun County, on the northeastern skirts of Beijing, launched a holiday promotion "Happy Warm Journey to Minyun," beckoning merrymakers to join the locals for the Chinese New Year.
文摘Nitrogen and phosphorus are the major nutrients to cause eutrophication to degrade water quality of the Miyun Reservoir, a very important drinking water source of Beijing, China, and they are mainly from non-point sources. The watershed in Miyun County was selected as the study region with a total area of 1400 km\+2. Four typical monitoring catchments and two experimental units were used to monitor the precipitation, runoff, sediment yield and pollutant loading related to various land uses in the meantime. The results show that the total nutrient loss amounts of TN and TP are \{898.07\} t/a, and \{40.70\} t/a, respectively, in which nutrients N and P carried by runoff are \{91.3%\} and \{77.3%\}, respectively. There is relatively heavier soil erosion in the northern mountain area whereas the main nutrient loss occurs near the northeast edge of the reservoir. Different land uses would influence the loss amounts of non-point source pollutants. The amount of nutrient loss from the agricultural land per unit is highest, that from forestry comes next and that from grassland is lowest. However, due to the variability of land use areas, agricultural land contributes a lot to TP and forestry lands to TN.
文摘In the Shixia small watershed, twenty experimental plots and two monitoring channels, the residential area and livestock areas were used to monitor the flow, runoff and erosion. Nitrogen and phosphorous concentrations associated with various land uses were analyzed at the same time. The results are presented as follows: (1) TP, TN and COD concentrations of runoff samples in the residential area and livestock areas are nearly 10 times those in other land-use areas. High nutrient loads are associated with village land use, which is due to unsuitable livestock rising. These areas should be treated as the critical areas of non-point source pollution. (2) Different land-use influences intensity the loss of nutrients, especially slope tillings in agricultural land. The amount of nutrient loss from agricultural land per unit is highest, that from forestry is intermediate and that from pastures is lowest. However, in consideration of the variability of land-use areas, agricultural land contributes the greatest to TP and forestry land to TN. (3) The concentrations of TN and TP in sediments from gangues are highest, those in forestry land are intermediate, and those in agricultural land are lowest. Nutrient loss from hilly areas is much greater than from mountainous areas.
基金Supported by the Science and Technology Project of Beijing (z111108057911004)Philosophy and Social Science Planning Projects of Beijing(11JGB049)
文摘Creative agriculture,a new agricultural format formed by integrating agriculture,tourism and creative industries,is an important part of the urban modern agriculture. Proceeding from the functional position as an ecological conservation area,Miyun creative agriculture has obtained rapid growth,relying on its ecological resources,agricultural resources,tourist resources and leisure industry advantages. But there are still some problems. On the basis of analyzing the advantages and problems of creative agriculture in Miyun,the paper put forward the basic principles and thought pattern of developing creative agriculture in there. Besides,several countermeasures in terms of resources integration, scientific planning,exploring local cultural resources,developing theme products,constructing industrial chain,carrying out project design and creative planning,creating creative agricultural advantage brand are put forward.
文摘为准确揭示密云水库流域径流变化的物理成因,基于降水、径流非平稳特征诊断结果,采用SWAT(soil and water assessment tool)水文模型,基于Budyko理论的弹性系数法和水量平衡法揭示该流域径流变化原因;对比验证各模型归因结果差异,进一步探究归因方法和基准期选择对流域径流变化归因结果的影响。结果表明:基于Budyko理论的水量平衡方法更适用于水利工程众多、跨流域调水活动频繁的密云水库流域径流变化归因计算;利用该方法进行分析,当基准期长度达到16年及以上时,流域径流变化归因分析结果逐渐趋于稳定,而基准期选取过短会高估人类活动对径流的减水效应;此外,基准期选取靠近研究初始时段时,计算得到人类活动的减水效应相对较大。综合考虑上述各因素的影响,认为人类活动是密云水库流域径流变化的主导因素;在变化期Ⅰ,其减水效应在-128.32%~-119.56%波动,在变化期Ⅱ,其对径流的削减作用为-75.58%~-70.70%。研究结果有助于提升对密云水库流域径流复杂演变规律和物理成因的科学认识。
