[Objective] The aim was to study on changing rules of physical and chemical properties of Eucalyptus uraphylla spp. forest at different ages in Southwest of Yunnan Province. [Method] In the research, field survey and ...[Objective] The aim was to study on changing rules of physical and chemical properties of Eucalyptus uraphylla spp. forest at different ages in Southwest of Yunnan Province. [Method] In the research, field survey and laboratory analysis were adopted to study on physical and chemical properties of soils for the Eucalyptus uraphylla spp. at the first cutting ages in Lancang County. [Result] With the increasing of forest ages, for physical properties of soils, soil bulk density was increasing, and soil structure became poor; water contents in soils and capillary porosity were improving, but total soil porosity and non-capillary porosity were decreasing. For chemical properties, pH of soil dropped, but soil acidity improved; organic matter, total N, hydrolysable nitrogen, available phosphorus, and available potassium all declined; exchangeable Ca and Mg were improving due to fertilization and Ca and Mg lower consumption. The results showed that plays important roles in water absorption of soils and vegetation growth were improved with age increase by Eucalyptus uraphylla spp. forest, but ventilation and fertility declined accordingly. [Conclusion] The research indicated that dry branches and fallen leaves should be preserved and nutrient cycling should be protected during introduction and management of Eucalyptus uraphylla spp. to guarantee the nutrients in dry branches and leaves are back to soils, providing theoretical references for management of forest plantation and environment protection.展开更多
[Objective] The aim was to analyze nutrients distribution and proportion in soils of farmlands of Gonggar County in Tibet. [Method] According to survey of soils in Tibet, nutrients of farmlands in Gonggar County were ...[Objective] The aim was to analyze nutrients distribution and proportion in soils of farmlands of Gonggar County in Tibet. [Method] According to survey of soils in Tibet, nutrients of farmlands in Gonggar County were analyzed and the countermeasures were proposed to achieve sustainable development of nutrients in soils. [Result] In Gonggar County in Tibet, farmlands with insufficient and less organic matter occupy 58.38%; farmlands with moderate contents of total N occupy 47.71%; farmlands with insufficient and less alkali-hydrolyzable nitrogen represent 82.36%; the farmlands with moderate and rich total P take up 49.40% and 21.59% ; farmlands with insufficient and less rapidly available P represent 67.33%; farmlands with richer and rich total K occupy 76.14% ; farmlands with moderate and insufficient rapidly available K represent 72.21%. [Conclusion] Based on nutrients in soils of farmlands, the countermeasures for sustainable utilization of nutrients in farmlands are proposed, including increase of organic fertilizer, soil testing and formulated fertilization and adjustment of acid-base balance.展开更多
Based on TM image data in 1989, 1995, 1999, 2003, 2006 and 2009 of Yanchi County of Ningxia, the land use date of Yanchi County in each year were extracted supported by RS and GIS technology, and used to analyze the d...Based on TM image data in 1989, 1995, 1999, 2003, 2006 and 2009 of Yanchi County of Ningxia, the land use date of Yanchi County in each year were extracted supported by RS and GIS technology, and used to analyze the dynamic change of land use. The land use data were studied for estimating the change of ecosystem services value caused by the land use change of Yanchi County, using the evaluation method of China terrestrial ecosystem services value. The results showed that the changes of land use were obvious during 1989 to 2009. The area of woodland and construction land had an increasing tendency; grassland area changed from decreasing to increasing, which was in contrary to farmland and un-used land areas (from increasing to decreasing); water area fluctuated slightly. The ecosystem services value of Yanchi County had an increasing tendency during 1989 to 1995, because the increasing woodland area had took the major role in raising the total ecosystem services value. The grassland accounted for a large proportion of the total ecosystem service value of Yanchi County, with its contribution rate from 49.8% to 60.4%. And the composition of the ecosystem services value of Yanchi County happened benign change for the increasing contribution rate of woodland. The ecosystem services value sensitivity index of each land use type was less than 1, indicating that the ecosystem services value of Yanchi County lacks flexibility on its service value index, and the research results are reliable.展开更多
This paper evaluated the impacts of mounds created by the plateau pika (Ochotona curzoniae) on the vegetation composition, structure, and species diversity of an alpine Kobresia steppe meadow in Nagqu County, Tibet ...This paper evaluated the impacts of mounds created by the plateau pika (Ochotona curzoniae) on the vegetation composition, structure, and species diversity of an alpine Kobresia steppe meadow in Nagqu County, Tibet Autonomous Region, China. Based on mound height or the depth of erosion pit, we defined five stages of erosion and compared the floristic features of communities at these stages with those in undisturbed sites. In the study area, the mounds and pits covered up to 7% of the total area. Lancea tibetica, Lamiophlomis rotata, and Potentilla biflarca were the dominant species in erosion pits, and Kobresia pygmaea, the dominant species in undisturbed sites, became a companion species in eroded areas. In the process of erosion, the original vegetation was covered by soil ejected by the pika, then the mounds were gradually eroded by wind and rain, and finally erosion pits formed. The vegetation coverage increased with increasing erosion stages but remained significantly lower than that in undisturbed sites. Improved coverage eventually reduced soil erosion, and pit depth eventually stabilized at around 20cm. Aboveground biomass increased with increasing erosion stage, but the proportion of low-quality forage reached more than 94%. The richness index and Shannon-Wiener index increased significantly with increasing erosion stage, but the richness index in mound and pit areas was significantly lower than that in undisturbed sites.展开更多
Rural landscape is a complex of natural landscape and human landscape, with various values. The recreational value of rural landscape is a kind of comprehensive benefit with economic, social and ecological, which is p...Rural landscape is a complex of natural landscape and human landscape, with various values. The recreational value of rural landscape is a kind of comprehensive benefit with economic, social and ecological, which is provided by the rural landscape as a recrea- tional resource. Loess Plateau is located at the junction of northern and northwestern of China, with serious water and soil erosion and fragile ecological environment. Jingning County is the national poor county, belonging to Liupanshan concentrated poverty areas. Hulu Watershed in Jingning is the typical valley area of Loess Plateau. In the past few decades, Jingning facing the fragile ecology and pov- erty, has been focusing on apple industry, forming unique rural landscape, exploring an ecological development path, and making much progress in green industrialization and urbanization. The author, according to the apple tree's growing stages, divided the rural landscape of Hulu Watershed into 15 types and analyzed its spatial patterns. The recreational value of Hulu Watershed was evaluated at 1.8 x 108-3.6 ~ 108 yuan (RMB) in 2014, by Travel Cost Method and Contingent Valuation Method. The territorial differentiational features of recreational value were that the higher value landscape types concentrated in the surrounding areas of towns and central vil- lages, and the areas along the traffic and river had more development potentiality. The main influence factors were the construction of rural landscape and the development of recreation industry. And the development paths of different landscape types were also proposed. The research conclusions can provide reference for the landscape exploration and recreation industry development in the similar underdeveloped areas in the valley area of Loess Plateau with fragile ecology and poverty.展开更多
By using soil erosion maps of four different time periods and a digital elevation model (DEM), in combination withthe remote sensing and GIS technologies, soil erosion dynamics in Xingguo County of Jiangxi Province in...By using soil erosion maps of four different time periods and a digital elevation model (DEM), in combination withthe remote sensing and GIS technologies, soil erosion dynamics in Xingguo County of Jiangxi Province in South Chinawere analyzed on both temporal and spatial scales in soils of different parent materials, altitudes and slopes. The resultsshowed that from 1958 to 2000 severe soil erosion was coming under control with a decreasing percentage of the land undersevere erosion. It was also found that the soils developed from Quaternary red clay, granite and purple shale were moresusceptible to soil erosion and that areas sitting between 200 to 500 m in altitude with a slope less than 3° or between7° to 20° where human activities were frequent remained to be zones where soil erosion was most likely to occur. Theseareas deserve special attention in monitoring and controlling.展开更多
Hyper-spectral data is widely used to determine soil properties. However, few studies have explored the soil spectral characteristics as response to soil erosion. This study analysed the spectral response of different...Hyper-spectral data is widely used to determine soil properties. However, few studies have explored the soil spectral characteristics as response to soil erosion. This study analysed the spectral response of different eroded soils in subtropical China, and then identify the spectral characteristics and soil properties that better discriminate softs with different erosion degrees. Two methods were compared: direct identification by inherent spectral characteristics and indirect identification by predictions of critical soft properties. Results showed that the spectral curves for different degrees of erosion were similar in morphology, while overall reflectance and characteristics of specific absorption peaks were different. When the first method is applied, some differences among different eroded groups were found by integration of associated indicators. However, the index of such indicators showed apparent mixing and crossover among different groups, which reduced the accuracy of identification. For the second method, the correlation between critical soil properties, such as soil organic matter (SOM), iron and aluminium oxides and reflectance spectra, was analysed. The correlation coefficients for the moderate eroded group were primarily between -0.3 to -0.5, which were worse than the other twogroups. However, the maximum value of R2 was obtained as 0.86 and 0.94 for the non-apparent eroded and the severe group. Furthermore, these two groups also showed some differences in the spectral response of iron complex state (Fep), Aluminium amorphous state (Alo) and the modelling results for soil organic matter (SOM). The study proved that it is feasible to identify different degrees of soil erosion by hyperspectral data, and that indirect identification by modelling critical soil properties and reflectance spectra is much better than direct identification. These results indicate that hyper-spectral data may represent a promising tool in monitoring and modelling soil erosion.展开更多
By analyses on the trace elements of coals,host-rocks and wall-rocks,this study aims to trace the sources and evaluate the utilization prospects of REE+Y(REY)in coals from Bayili Coal Mine(Wensu,Xinjiang,China).The di...By analyses on the trace elements of coals,host-rocks and wall-rocks,this study aims to trace the sources and evaluate the utilization prospects of REE+Y(REY)in coals from Bayili Coal Mine(Wensu,Xinjiang,China).The distribution patterns of REY in the coals are divided into two groups,flat-type and heavy REE-enrichment type(H-type).The REY of the former was mainly from the gneisses of the basement of the coal-bearing basin,and that of the later was partly from hydrothermal solution.The host-rocks show two types of REY patterns,middle REE-enrichment type(M-type)and H-type,which are due to the injection of REY from acid terrestrial water and hydrothermal solution,respectively.Almost all the coal samples are plotted into the promising area on the diagram of percentage of critical elements(REY_(def,rel))vs ratio of sum of critical elements to the sum of excessive elements(C_(outl))and half of the coal samples have high contents of Ga closing to the cut-off grade of Ga deposit as by-product,which indicate that the REY and Ga in Bayili Coal Mine are of utilization prospects as by-product.展开更多
Adjusting and optimizing land use structure is one of the essential approaches to solve the conflict between land supply and demand. In this study,an uncertain interval multi-objective linear programming model was est...Adjusting and optimizing land use structure is one of the essential approaches to solve the conflict between land supply and demand. In this study,an uncertain interval multi-objective linear programming model was established and applied to analyzing the suitability of land use structure in Pi County of Sichuan Province. An adjustment scheme for optimizing land use structure was proposed on the basis of development planning drawn up by the local government. The results are summarized as follows: 1) the optimal adjustment scope for cropland area ranges from 27 976.75 ha to 31 029.08 ha,and the current area is less than the lower limit of the scope; 2) the optimal adjustment scope for garden land area ranges from 4 736.49 ha to 12 967.11 ha,and the current area is less than the lower limit; 3) the optimal adjustment scope for construction land ranges from 7 761.95 ha to 10 393.18 ha,and the current area is greater than the upper limit; 4) the optimal adjustment scope for industry and mining land ranges from 557.29 ha to 693.54 ha,and the current area exceeds the upper limit; and 5) the areas of forest land,grassland and other agricultural land are within the optimal adjustment scope. In order to maximize comprehensive benefit with the limited resources and the demand of sustainable development,the areas of cropland and garden land are supposed to be expanded properly,while the construction land should be controlled and reduced gradually,and the forest land and other agricultural land can be maintained at the current level in short period.展开更多
This study is to explore a suitable method to classify landform, in order to support the decision making for community siting in mountainous areas.It first proposes the landform classification for community siting(LCC...This study is to explore a suitable method to classify landform, in order to support the decision making for community siting in mountainous areas.It first proposes the landform classification for community siting(LCCS) method with detailed discussions on its rationality and the chosen parameters.This method is then tested and verified in Quxian county.The LCCS method entails twograde parameters, which uses relative relief as the first grading parameter, slope as the second, followed by a synthesis process to form a suitable landform classification system.By applying the LCCS method in Quxian county, the result shows that its use of watershed to identify geomorphometric units, and its use of the altitude datum concept, can effectively classify landform according to the local cultural traditions, and the economic and environmental conditions.The verification result shows that comparing to the conventional methods, the LCCS method respects to people's daily experience due to its bottom-up approach.It not only help to minimize the disturbance to the nature when choosing locations for community development, but also helps to prepare more precise land management policies,which maximizes agricultural production and minimizes terrain transformation.展开更多
With the help of ARC/INFOR and ERDAS software, based on the information from forest resources distribution maps and TM images, four indices were chosen to analyze spatial pattern changes of forest landscape of Luoning...With the help of ARC/INFOR and ERDAS software, based on the information from forest resources distribution maps and TM images, four indices were chosen to analyze spatial pattern changes of forest landscape of Luoning County, Henan Province from 1983 to 1999. The results showed that: 1) The number and total area of patches were rapidly increased with time changes. The fragmentation degree of the landscape was increasing greatly. 2) The area of some forest patch types, especially shrub forest, economic forest, Populus spp. forest, Quercus spp. forest, sparse forest, deserted grassland etc. had been greatly changed. 3) The fragemation degree of each forest patch type became greater from 1983 to 1999. 4) The transition probabilities of deserted forest, economic forest, Pi-nus tabulaeformis forest, Populus spp. forest exceed 85%,Robinia pseuoacacia forest, deserted grassland, 65% and Quercus spp. forest, non-forest, shrub forest had smaller ones, which were 26.5%, 29.1% and 45.3%, respectively. The main transition trends of various patches were non-forest and Quercus spp. forest. During the course of transition, the types that 50% of area was remained were Quercus spp. forest, non-forest and shrub forest. According to above analyses, the main driving forces, such as the management policies, market economy factors and influences of human activities etc. were brought out.展开更多
Studies related to the quantitation and distribution of soil organic carbon (C) under different land use types can help to fill the knowledge gaps regarding estimation of the amount of C stored in soils at a global ...Studies related to the quantitation and distribution of soil organic carbon (C) under different land use types can help to fill the knowledge gaps regarding estimation of the amount of C stored in soils at a global scale. Orchards are an important land use type in southern China; the total area (1.15 x 107 ha) of orchards in China comprises approximately 20.5% of the area of all orchards worldwide. We assessed soil organic C stocks (SOCS) in citrus orchards in Yongchun County (consisting of 22 towns), Fujian Province, China in 1982 and 2010. The southeastern part of the county, an area featuring extensive citrus farming with a gently sloping landscape and low rates of water erosion, had the highest SOCS. In contrast, the lowest SCOS was observed in the northern part of the county, where steep hills with severe erosion problems are common and citrus orchards are sparsely distributed. From 1982 to 2010, the mean SOCS in citrus orchards increased from 22.1 to 41.7 Mg ha-1 which indicated that current management practices such as fertilization, irrigation, and cultivation enhanced soil C stocks. Further in-depth studies on the effects of these practices on C sequestration would be worthwhile and surveys of SOCS throughout Fujian Province are needed, to support efforts to mitigate global C emission.展开更多
基金Supported by National Natural Science Foundation of China (40961031)Applied Basic Research Programs of Yunnan Province (2009CD022)Young and Middle-aged Teachers Training of Yunnan University (XT412003)~~
文摘[Objective] The aim was to study on changing rules of physical and chemical properties of Eucalyptus uraphylla spp. forest at different ages in Southwest of Yunnan Province. [Method] In the research, field survey and laboratory analysis were adopted to study on physical and chemical properties of soils for the Eucalyptus uraphylla spp. at the first cutting ages in Lancang County. [Result] With the increasing of forest ages, for physical properties of soils, soil bulk density was increasing, and soil structure became poor; water contents in soils and capillary porosity were improving, but total soil porosity and non-capillary porosity were decreasing. For chemical properties, pH of soil dropped, but soil acidity improved; organic matter, total N, hydrolysable nitrogen, available phosphorus, and available potassium all declined; exchangeable Ca and Mg were improving due to fertilization and Ca and Mg lower consumption. The results showed that plays important roles in water absorption of soils and vegetation growth were improved with age increase by Eucalyptus uraphylla spp. forest, but ventilation and fertility declined accordingly. [Conclusion] The research indicated that dry branches and fallen leaves should be preserved and nutrient cycling should be protected during introduction and management of Eucalyptus uraphylla spp. to guarantee the nutrients in dry branches and leaves are back to soils, providing theoretical references for management of forest plantation and environment protection.
基金Supported by Fund from Science and Technology Department of Tibet Autonomous Region ([2009]162)~~
文摘[Objective] The aim was to analyze nutrients distribution and proportion in soils of farmlands of Gonggar County in Tibet. [Method] According to survey of soils in Tibet, nutrients of farmlands in Gonggar County were analyzed and the countermeasures were proposed to achieve sustainable development of nutrients in soils. [Result] In Gonggar County in Tibet, farmlands with insufficient and less organic matter occupy 58.38%; farmlands with moderate contents of total N occupy 47.71%; farmlands with insufficient and less alkali-hydrolyzable nitrogen represent 82.36%; the farmlands with moderate and rich total P take up 49.40% and 21.59% ; farmlands with insufficient and less rapidly available P represent 67.33%; farmlands with richer and rich total K occupy 76.14% ; farmlands with moderate and insufficient rapidly available K represent 72.21%. [Conclusion] Based on nutrients in soils of farmlands, the countermeasures for sustainable utilization of nutrients in farmlands are proposed, including increase of organic fertilizer, soil testing and formulated fertilization and adjustment of acid-base balance.
基金supported by the National Key Technology R&D Program of China(2012BAD16B02)National Forestry Public Welfare Industry Research of China(201004018)~~
文摘Based on TM image data in 1989, 1995, 1999, 2003, 2006 and 2009 of Yanchi County of Ningxia, the land use date of Yanchi County in each year were extracted supported by RS and GIS technology, and used to analyze the dynamic change of land use. The land use data were studied for estimating the change of ecosystem services value caused by the land use change of Yanchi County, using the evaluation method of China terrestrial ecosystem services value. The results showed that the changes of land use were obvious during 1989 to 2009. The area of woodland and construction land had an increasing tendency; grassland area changed from decreasing to increasing, which was in contrary to farmland and un-used land areas (from increasing to decreasing); water area fluctuated slightly. The ecosystem services value of Yanchi County had an increasing tendency during 1989 to 1995, because the increasing woodland area had took the major role in raising the total ecosystem services value. The grassland accounted for a large proportion of the total ecosystem service value of Yanchi County, with its contribution rate from 49.8% to 60.4%. And the composition of the ecosystem services value of Yanchi County happened benign change for the increasing contribution rate of woodland. The ecosystem services value sensitivity index of each land use type was less than 1, indicating that the ecosystem services value of Yanchi County lacks flexibility on its service value index, and the research results are reliable.
基金Under the auspices of the Science and Technology Committee of Tibet Autonomous Region (No. 200101046)
文摘This paper evaluated the impacts of mounds created by the plateau pika (Ochotona curzoniae) on the vegetation composition, structure, and species diversity of an alpine Kobresia steppe meadow in Nagqu County, Tibet Autonomous Region, China. Based on mound height or the depth of erosion pit, we defined five stages of erosion and compared the floristic features of communities at these stages with those in undisturbed sites. In the study area, the mounds and pits covered up to 7% of the total area. Lancea tibetica, Lamiophlomis rotata, and Potentilla biflarca were the dominant species in erosion pits, and Kobresia pygmaea, the dominant species in undisturbed sites, became a companion species in eroded areas. In the process of erosion, the original vegetation was covered by soil ejected by the pika, then the mounds were gradually eroded by wind and rain, and finally erosion pits formed. The vegetation coverage increased with increasing erosion stages but remained significantly lower than that in undisturbed sites. Improved coverage eventually reduced soil erosion, and pit depth eventually stabilized at around 20cm. Aboveground biomass increased with increasing erosion stage, but the proportion of low-quality forage reached more than 94%. The richness index and Shannon-Wiener index increased significantly with increasing erosion stage, but the richness index in mound and pit areas was significantly lower than that in undisturbed sites.
基金Under the auspices of National Natural Science Foundation of China(No.41271556,41301637)
文摘Rural landscape is a complex of natural landscape and human landscape, with various values. The recreational value of rural landscape is a kind of comprehensive benefit with economic, social and ecological, which is provided by the rural landscape as a recrea- tional resource. Loess Plateau is located at the junction of northern and northwestern of China, with serious water and soil erosion and fragile ecological environment. Jingning County is the national poor county, belonging to Liupanshan concentrated poverty areas. Hulu Watershed in Jingning is the typical valley area of Loess Plateau. In the past few decades, Jingning facing the fragile ecology and pov- erty, has been focusing on apple industry, forming unique rural landscape, exploring an ecological development path, and making much progress in green industrialization and urbanization. The author, according to the apple tree's growing stages, divided the rural landscape of Hulu Watershed into 15 types and analyzed its spatial patterns. The recreational value of Hulu Watershed was evaluated at 1.8 x 108-3.6 ~ 108 yuan (RMB) in 2014, by Travel Cost Method and Contingent Valuation Method. The territorial differentiational features of recreational value were that the higher value landscape types concentrated in the surrounding areas of towns and central vil- lages, and the areas along the traffic and river had more development potentiality. The main influence factors were the construction of rural landscape and the development of recreation industry. And the development paths of different landscape types were also proposed. The research conclusions can provide reference for the landscape exploration and recreation industry development in the similar underdeveloped areas in the valley area of Loess Plateau with fragile ecology and poverty.
基金the National Natural Science Foundation of China (No. 40471081), the Innovation Programme ofChinese Academy of Sciences (No. KZCX3-SW-422), and the Canadian International Development Agency, Canada.
文摘By using soil erosion maps of four different time periods and a digital elevation model (DEM), in combination withthe remote sensing and GIS technologies, soil erosion dynamics in Xingguo County of Jiangxi Province in South Chinawere analyzed on both temporal and spatial scales in soils of different parent materials, altitudes and slopes. The resultsshowed that from 1958 to 2000 severe soil erosion was coming under control with a decreasing percentage of the land undersevere erosion. It was also found that the soils developed from Quaternary red clay, granite and purple shale were moresusceptible to soil erosion and that areas sitting between 200 to 500 m in altitude with a slope less than 3° or between7° to 20° where human activities were frequent remained to be zones where soil erosion was most likely to occur. Theseareas deserve special attention in monitoring and controlling.
文摘Hyper-spectral data is widely used to determine soil properties. However, few studies have explored the soil spectral characteristics as response to soil erosion. This study analysed the spectral response of different eroded soils in subtropical China, and then identify the spectral characteristics and soil properties that better discriminate softs with different erosion degrees. Two methods were compared: direct identification by inherent spectral characteristics and indirect identification by predictions of critical soft properties. Results showed that the spectral curves for different degrees of erosion were similar in morphology, while overall reflectance and characteristics of specific absorption peaks were different. When the first method is applied, some differences among different eroded groups were found by integration of associated indicators. However, the index of such indicators showed apparent mixing and crossover among different groups, which reduced the accuracy of identification. For the second method, the correlation between critical soil properties, such as soil organic matter (SOM), iron and aluminium oxides and reflectance spectra, was analysed. The correlation coefficients for the moderate eroded group were primarily between -0.3 to -0.5, which were worse than the other twogroups. However, the maximum value of R2 was obtained as 0.86 and 0.94 for the non-apparent eroded and the severe group. Furthermore, these two groups also showed some differences in the spectral response of iron complex state (Fep), Aluminium amorphous state (Alo) and the modelling results for soil organic matter (SOM). The study proved that it is feasible to identify different degrees of soil erosion by hyperspectral data, and that indirect identification by modelling critical soil properties and reflectance spectra is much better than direct identification. These results indicate that hyper-spectral data may represent a promising tool in monitoring and modelling soil erosion.
基金the National Natural Science Foundation of China(Nos.42004107,42074165)the Open Research Fund Program of Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring(Central South University)+1 种基金Ministry of Education,China(No.2019YSJS13)Department of Water Resources of Hunan Province,China(No.XSKJ2019081).
文摘By analyses on the trace elements of coals,host-rocks and wall-rocks,this study aims to trace the sources and evaluate the utilization prospects of REE+Y(REY)in coals from Bayili Coal Mine(Wensu,Xinjiang,China).The distribution patterns of REY in the coals are divided into two groups,flat-type and heavy REE-enrichment type(H-type).The REY of the former was mainly from the gneisses of the basement of the coal-bearing basin,and that of the later was partly from hydrothermal solution.The host-rocks show two types of REY patterns,middle REE-enrichment type(M-type)and H-type,which are due to the injection of REY from acid terrestrial water and hydrothermal solution,respectively.Almost all the coal samples are plotted into the promising area on the diagram of percentage of critical elements(REY_(def,rel))vs ratio of sum of critical elements to the sum of excessive elements(C_(outl))and half of the coal samples have high contents of Ga closing to the cut-off grade of Ga deposit as by-product,which indicate that the REY and Ga in Bayili Coal Mine are of utilization prospects as by-product.
基金Under the auspices of National Key Technology R&D Program of China (No. 2006BAB04A08)
文摘Adjusting and optimizing land use structure is one of the essential approaches to solve the conflict between land supply and demand. In this study,an uncertain interval multi-objective linear programming model was established and applied to analyzing the suitability of land use structure in Pi County of Sichuan Province. An adjustment scheme for optimizing land use structure was proposed on the basis of development planning drawn up by the local government. The results are summarized as follows: 1) the optimal adjustment scope for cropland area ranges from 27 976.75 ha to 31 029.08 ha,and the current area is less than the lower limit of the scope; 2) the optimal adjustment scope for garden land area ranges from 4 736.49 ha to 12 967.11 ha,and the current area is less than the lower limit; 3) the optimal adjustment scope for construction land ranges from 7 761.95 ha to 10 393.18 ha,and the current area is greater than the upper limit; 4) the optimal adjustment scope for industry and mining land ranges from 557.29 ha to 693.54 ha,and the current area exceeds the upper limit; and 5) the areas of forest land,grassland and other agricultural land are within the optimal adjustment scope. In order to maximize comprehensive benefit with the limited resources and the demand of sustainable development,the areas of cropland and garden land are supposed to be expanded properly,while the construction land should be controlled and reduced gradually,and the forest land and other agricultural land can be maintained at the current level in short period.
基金supported by the National Natural Science Foundation of China(Grant Nos.51478056 and 51208202)
文摘This study is to explore a suitable method to classify landform, in order to support the decision making for community siting in mountainous areas.It first proposes the landform classification for community siting(LCCS) method with detailed discussions on its rationality and the chosen parameters.This method is then tested and verified in Quxian county.The LCCS method entails twograde parameters, which uses relative relief as the first grading parameter, slope as the second, followed by a synthesis process to form a suitable landform classification system.By applying the LCCS method in Quxian county, the result shows that its use of watershed to identify geomorphometric units, and its use of the altitude datum concept, can effectively classify landform according to the local cultural traditions, and the economic and environmental conditions.The verification result shows that comparing to the conventional methods, the LCCS method respects to people's daily experience due to its bottom-up approach.It not only help to minimize the disturbance to the nature when choosing locations for community development, but also helps to prepare more precise land management policies,which maximizes agricultural production and minimizes terrain transformation.
文摘With the help of ARC/INFOR and ERDAS software, based on the information from forest resources distribution maps and TM images, four indices were chosen to analyze spatial pattern changes of forest landscape of Luoning County, Henan Province from 1983 to 1999. The results showed that: 1) The number and total area of patches were rapidly increased with time changes. The fragmentation degree of the landscape was increasing greatly. 2) The area of some forest patch types, especially shrub forest, economic forest, Populus spp. forest, Quercus spp. forest, sparse forest, deserted grassland etc. had been greatly changed. 3) The fragemation degree of each forest patch type became greater from 1983 to 1999. 4) The transition probabilities of deserted forest, economic forest, Pi-nus tabulaeformis forest, Populus spp. forest exceed 85%,Robinia pseuoacacia forest, deserted grassland, 65% and Quercus spp. forest, non-forest, shrub forest had smaller ones, which were 26.5%, 29.1% and 45.3%, respectively. The main transition trends of various patches were non-forest and Quercus spp. forest. During the course of transition, the types that 50% of area was remained were Quercus spp. forest, non-forest and shrub forest. According to above analyses, the main driving forces, such as the management policies, market economy factors and influences of human activities etc. were brought out.
基金supported by the National Key Technology R&D Program of China (No.2012BAD14B15)
文摘Studies related to the quantitation and distribution of soil organic carbon (C) under different land use types can help to fill the knowledge gaps regarding estimation of the amount of C stored in soils at a global scale. Orchards are an important land use type in southern China; the total area (1.15 x 107 ha) of orchards in China comprises approximately 20.5% of the area of all orchards worldwide. We assessed soil organic C stocks (SOCS) in citrus orchards in Yongchun County (consisting of 22 towns), Fujian Province, China in 1982 and 2010. The southeastern part of the county, an area featuring extensive citrus farming with a gently sloping landscape and low rates of water erosion, had the highest SOCS. In contrast, the lowest SCOS was observed in the northern part of the county, where steep hills with severe erosion problems are common and citrus orchards are sparsely distributed. From 1982 to 2010, the mean SOCS in citrus orchards increased from 22.1 to 41.7 Mg ha-1 which indicated that current management practices such as fertilization, irrigation, and cultivation enhanced soil C stocks. Further in-depth studies on the effects of these practices on C sequestration would be worthwhile and surveys of SOCS throughout Fujian Province are needed, to support efforts to mitigate global C emission.