With the development of economic globalization and regional integration, China has continuously developed “go global” strategy to encourage enterprises to invest in foreign countries and regions. After the 21st century, China’s foreign direct investment flows continued to grow. Affected by “the Belt and Road” strategy, Southeast Asia has become a hot spot for China’s outward foreign direct investment. In order to enrich and perfect the location theory and investment strategy of China’s direct investment in Southeast Asia, the article takes Southeast Asia as the research area. The existing traditional outward foreign direct investment theories are mostly based on the state as a whole, and study the influencing factors and motivations of outward foreign direct investment from the macro inspect. However, with the development of the times, the emerging theories show us that the heterogeneity of the enterprise will bring about the difference of outward foreign direct investment, and the difference of ownership is what we are going to probe into. Therefore, the article uses direct investment projects of Chinese enterprises in Southeast Asia from 2005 to 2015 as research samples, and chooses the real exchange rate, trade linkage, relative market size, wage level, infrastructure, total tax and political risk as explanatory variables to compare the different motivations and influencing factors of Chinese state-owned enterprises and private enterprises in the outward foreign direct investment in Southeast Asia. The empirical results show that state-owned enterprises tend to invest in high political risk countries and countries that are not in a close trade linkage with China. On the contrary, private enterprises tend to invest in low political risk countries and countries that are in a close trade linkage with China, with relatively large market size and lower labor costs. Finally, based on the differences between the influencing factors and motivations of the outward foreign direct investment of the state-owned enterprises and the private enterprises in Southeast Asia, the article gives some suggestions for China's direct investment in Southeast Asia.
The adjustment of administrative divisions is an important means to improve the efficiency of administrative management and promote economic development, which can often change the potential and development track of an administrative region, and reshape the vitality of urban development and regional development pattern. By quantitatively measuring the change of the potential caused by the administrative division adjustment, the effectiveness of the administrative division adjustment can be evaluated, and the internal relations with the social and economic development can be measured. This article tries to establish a quantitative measurement model of the potential of administrative region derived from Cobb-Douglas production function. Taking Chongqing City as a case, the article calculates the potential and the relative energy of the adjustment of the municipality before and after the establishment of the municipality directly under the central government, in order to explore and analyze the mechanism that affects the change of potential of an administrative region. Researches show that: 1) The potential of administrative region is related to the traffic accessibility, resource control capacity and comprehensive development scale. And there is interaction between each factor and it. 2) Administrative division adjustment has a positive effect on the change of potential of administrative region, but the effect has lag effect and cannot be realized in a short time. 3) The establishment of Chongqing Municipality does not only mean the promotion of the administrative level, but also the increasing potential of administrative region. Its relative potential of administrative region is greater than 1 since the establishment of municipality, but the increase range is changed from the rapid tends to develop slowly. 4) With the establishment of the Chongqing Municipality, the construction of its transportation network has been gradually improved, the financial management has been successfully transformed, the economic growth has been rapid, and the financial and economic win-win situation has been achieved. Compared to the pre zoning adjustment period, the regional comparative advantages are prominent, and the competitive power is becoming more and more outstanding. This article puts forward new vision and new methods from the perspective of administrative region potential to measure the influence of administrative division adjustment quantitatively, whose deficiency is that the indicators for measuring the resource control capacity in case areas are not comprehensive, and the research area of this paper, Chongqing City, has its particularity. In the future, we will focus on the change of the effectiveness of the administrative division adjustment in the general regions, so as to gradually deepen the understanding of the political location potential.
In order to reveal the coupling relationships among space exploitation, economy development and environment evolution, we introduce the concept of coupling degree and build the evaluation index system which includes 36 indicators embodying these three aspects. By using variable coefficient method, trend surface model and multiple regression model, we analyze the characteristics and mechanism of the differentiation of coupling degrees among space exploitation, economy development, environment evolution in Harbin-Dalian Giant Urban Belt during 2000-2014. The results show that: 1) The coupling degrees of space exploitation, economy development and environment evolution have demonstrated different levels of imbalance since 2000, and the degrees in west area are higher than those in east area. Even so, the coupling degrees are overall rising. The coupling degrees in Harbin-Changchun sub-district, the central and southern Liaoning Province sub-district and Harbin-Dalian Giant Urban Belt rose at the beginning, then reduced, which shows a good trend on the whole. 2) Government investment had a significant effect on the differentiation of coupling degree in Harbin-Dalian Giant Urban Belt in 2000. Science and technology input intensity and capital input intensity are the leading factors in 2007 and 2014. The differences of urban development energy level and coupling degree among cities were consistent in 2007. 3) Under the influence of science and technology input, government input and capital input, in Harbin-Changchun sub-district, the coupling degrees among space exploitation, economy development and environment evolution show significant differences, but in central and southern Liaoning Province sub-district, the influencing factors of differentiations of coupling degree changed gradually from human capital efficiency and administrative rank to capital input intensity.
Optimizing the spatial structure of urban population distribution is one of the key strategies in China, and central government has made clear that we should adhere to the coordinated development of large, medium and small cities. At the same time, the income gap that stimulates the flow of population continues to expand, the Hukou system is becoming flexible, and the technologies in transportation, information and communication have been largely improved, which have further promoted the outward flow of the population. Hence, the focus of China’s urbanization should shift from improving the urbanization rate to optimizing spatial efficiency, and it is of great importance to understand the characteristics, evolution and the formation mechanisms of urban spatial structure. Based on the 2000 and 2010 censuses, this paper describes the features of spatial structure in Chinese prefecture-level city regions by three different indexes: Pareto exponent, HHI and Primacy index. It has found that, from the static point of view, city-regions in the southeastern side of Hu line is much more polycentric than the northwestern side ones; and from the view of dynamic process, the spatial structure is rather stable on the whole and has a weak tendency towards polycentricity. Also this paper constructs a comprehensive framework by covering the factors of physical geography, socio-economy and government intervention to systematically examine the influential factors of regional spatial structure. Traditional location theory and economic geography have confirmed the role of physical geography in economic agglomeration and urban formation, and the level of social-economic development and the government have jointly decided the development and evolution of regional spatial structure in China. Our empirical results show, the spatial structure of Chinese city-regions is mainly affected by the role of government intervention, and physical geography and social economic factors on regional spatial structure is relatively limited. Specifically, surface roughness, hierarchy level of cities and government expenditure ratio will bring the regional spatial structure into monocentricity, while administrative land area, the number of NDZs, competition between local governments, and per capita road mileage can make the spatial structure more polycentric. Our previous studies have come to the conclusion that, prefecture cities with a more monocentric spatial structure have a higher labor productivity. Combined with this, the conclusions of this paper have important implications for the future development of new urbanization in China. The finding that urban spatial structure is mainly affected by the visible hand of government might not be a good sign. Government policies are often multi-targets, and its goals, in most cases, are not for the improvement of the spatial structure, but only an additional effect. This also explains why the governmental interventions are often contradictory with each other.
The carbon emissions intensities of China’s thirty provinces caused by energy consumption were calculated according to the reference approach provided by IPCC. Exploratory spatial data analysis (ESDA), space-time transition measurement method and geographically weighted regression (GWR) model were employed to analyze the spatial dependence of provincial carbon emissions intensity and spatial heterogeneity of its driving factors from 1995 to 2015. The results were shown as follows: 1) There was a significant positive spatial correlation in carbon emissions intensity among provinces. Global spatial autocorrelation decreased first and then increased and last fluctuated slightly. The provinces with similar carbon intensity tended to be agglomerate, indicating that provincial carbon intensity had an obvious spatial dependence characteristics. 2) An uneven development pattern of carbon emission intensity existed in China's provinces. The provinces with H-H agglomeration were mainly distributed in the northwest of China, while the ones with L-L agglomeration mainly distributed in the southeast of China. 3) The spatial agglomeration of carbon intensity presented an overall trend of optimization, the provinces with H-H agglomeration decreased, while ones with L-L agglomeration increased. However, different provinces played different roles in the spatial agglomeration of carbon intensity. 4) The driving factors of carbon emissions intensity had obvious spatial heterogeneity among China’s provinces, and there was a positive correlation between the 4 explanatory variables and carbon intensity. The influence degree of 4 explanatory variables on carbon intensity was as follows: energy intensity>energy structure>industrial structure>per capita GDP. Different policies of carbon intensity reduction should be formulated according to the actual situation of each province. Therefore, in order to achieve regional differences in carbon emission reduction, it is necessary to take full account of the actual situation of carbon intensity in each province and the spatial differences of carbon intensity affected by different factors.
With the rapid development of the modern logistics industry dominated by the port logistics in China's coastal cities, researches on the characteristics of spatial distribution and laws of evolution of the port logistics companies inside cities are beginning to appear. However, the existing research has not further studied the factors affecting the location selection of the port logistics companies. In this article, based on the data of location information of Ningbo port logistics companies, the characteristics of spatial distribution and factors that affect the location selection of the port logistics companies are analyzed. The differences of the locational characteristics between the different types of port logistics companies are identified. It enriches the case studies of the locational analysis of the port logistics companies in the coastal cities. Taking Ningbo as an example, this article employed the Kernel Density Estimation, Getis-ord Gi analysis and Poisson regression models to analyze data, and the results showed that: 1) The port logistics companies in Ningbo show centripetal concentration, and the spatial distribution of enterprises presents a tendency to decrease from the central city, the periphery to the suburbs, and the distribution pattern of the circle is obvious. Central business district and port industrial area are the popular areas for port logistics enterprises to gather. 2) At present, port logistics enterprises have obvious agglomeration characteristics, but the overall agglomeration degree is decreasing. At the same time, there are two trends, which are centralization and diffusion of central business district and port industrial area. 3) It is found that there are obvious differences in location choice of different types of port logistics companies: a) The freight forwarder logistics companies are mainly distributed in the central business area; b) The logistics business companies of warehouse are mainly distributed in port; c) The transportation logistics companies often choose the layout along the main road, because they mainly undertake land container transportation, the locational selection has traffic dependency; d) Compared with the other three types, the distribution of integrated logistics companies has no obvious locational tendencies. 4) Regarding the factors affecting the spatial distribution of Ningbo port logistics companies, the research shows that the policy factors, the price of land, the differences between urban and rural areas, the distance from the port, the economic potential of the region and its industrial structure all affect the spatial distribution of port logistics enterprises in varying degrees. However, there is no correlation with traffic convenience, and the main reason is that the road network construction in Ningbo is relatively perfect. At the same time, the article put forward the corresponding measures from three different aspects: first, strengthening top-level design in logistics industry; second, exploiting the regional advantages to form a park that integrates port logistics and port industry advantages;third, optimizing the infrastructure such as the traffic network deeply.
Based on the business data between 1999-2013, this paper analyzed the industrial adjustment and spatial differentiation of the main airport economic zones in the Yangtze River Delta, Conclusions are as follows: 1) With the development of airport economic zones, both hub-orientation industry and none hub-orientation industry have a rapid growth, but percentage of the hub-orientation industry are lower than 25%, the airport economic zones in Yangtze River Delta is still at the stage of quantity expanding. 2) The concentration space of industries are different, with the development of airport economic zones, the hub-orientation industry had radial clusters while the none hub-orientation industry had the centrifugal layout.Now the hub-orientation industry in the Yangtze River Delta only has the concentration advantage in the three minutes time circle. 3) Different industries had different expanding speed, influenced by the flexible location and specificity of none hub-orientation, service industry and none hub-orientation industry expanded rapidly, while the manufacture industry and the hub-orientation industry’s concentration space is stable. 4) The comprehensive development level of airport economic zones determines whether the circles’ differentiation is clear or not. A deeper industrial analysis shows that it is easier for relatively mature airport economic zone to form a industrial distribution pattern ,while in the immature airport economic zone, industry with different hub-orientation has mixed layout.With the exception of maturity level, the hub-orientation, airport’s location and the construction land space of airport economic zones also have strong influence on the spatial differentiation in the airport economic zone.
Agriculture, rural areas and farmers have always been the fundamental issues concerning the national economy and people’s livelihood. China’s heavy investment in urban areas for a long time aimed solely at economic development at the expense of agriculture, thereby lead to a huge gap between urban and rural areas. In order to bridge the gap between urban and rural areas in China, development of the countryside is the priority. Therefore, taking agriculture as the starting point and driving force for rural development can promote rural economic development and sustainable agricultural development. At present the structure and type of rural agricultural functions have gradually begun to upgrade, evolving from the traditional, single function to multi-functional. Therefore domestic and foreign scholars have gradually increased their research on multi-functions in agriculture, mainly focusing on the evaluation and division. But, there is lack of research on the spatio-temporal dynamics, in particular, on the regulatory pathways for the evolution of agricultural functions. Based on the data from land use detailed surveys in the Changsha-Zhuzhou-Xiangtan urban agglomerations from 1998 to 2014, the study analyzed the spatio-temporal dynamics of agricultural function by agricultural regional multi-function index and regional agricultural function spatio-temporal differences identifying model. And it covers four aspects: the agricultural products supplying function, the labor employment and social security function, the ecological conservation function, and the cultural heritage and recreational function. The results showed that the agricultural products supplying function was enhanced and its core has the tendency to spread. The labor employment and social security function weakened to a large extent. The ecological conservation function in hilly area also enhanced. The cultural heritage and recreational function gained prominence in the urban areas.The study found that different regions have different dominant functions of agriculture, based on the characteristics and advantages of agricultural functions in different regions. Combining with the characteristics,we should develop superior agriculture functions suitable for local conditions and put forward corresponding optimization and control measures, thus providing a theoretical basis for identification and determination of multi-functional agriculture development and functional characteristics in Changsha-Zhuzhou-Xiangtan urban agglomerations.
Water Poverty and Agricultural Modernization are two important issues that affects Chinese security and economic development. Studying the coupling relationship between them contributes to promoting the sustainable development of resources environment and economy. The paper selected 30 provincial areas of China including autonomous regions as the research unit. Firstly, the water poverty and agricultural modernization’s evaluation index system was set up, the poverty model and the agricultural modernization index were used to calculate the poverty value and agricultural modernization value of each province, and the time series map was established respectively. Then, the spatial distribution of the two was carried out by ArcGIS. Finally, using the coupling coordination model and the coupled coordination Gini coefficient analyze rural water poverty and agricultural modernization coupling coordination and regional differences, as well as using spatial antocorrelation to analyze the spatio-temporal relationship of rural water poverty, agricultural modernization and coupling coordination from 2005 to 2014. The results are obtained as follows: ① The degree of rural water poverty in China decreases by 14.68%.The reason for the decline is mainly the implementation of the 10th Five-year Plan. The central water conservancy work attached great importance to solving the water problem in an important position and made a series of major arrangements and water conservancy investments to maintain a high level. But the degree of water poverty fluctuated in that period due to natural disasters of some areas such as rare historical rainfall, typhoons and droughts. The decreasing amplitude in eastern and western China is smaller than that in central China, maintaining the decreasing tendency of “central-west-east”. The degree of rural water poverty in China was positive spatial autocorrelation within a decade. ② Agricultural modernization level slowly increases by 5.5%. The eastern provinces of the agricultural modernization level are kept above the national average, while the central and western regions are kept below the national average. Although the western China increases by 26.88%, the degree of rural water poverty continues the decreasing trend of “east-central-west”.③ The coordination degree of rural water poverty and agricultural modernization are fluctuating, indicating that the corresponding spatial scale keeps the rising trend. In recent years, the increase of coordination degree is 8.03 %.The regional differences of coordination degree between water poverty and agricultural modernization level tend to decline and the Gini index increases by 31.62%. The index in the western region is much higher than eastern region, but the coordination degree has maintained the increasing tendency of “east-central-west”. ④ The “cold-spot” areas of the coordination degree between water poverty and agricultural modernization level shows the contraction tendency while “hot-spot” areas shows the expansion tendency. Finally, this paper makes suggestions how to reduce the rural water poverty, improve the level of agricultural modernization and coordinate them.
The article uses the index of trade combination degree to analyze the dependence of China and Nigeria on each other, and summarize the characteristics of China's investment and trade with Nigeria. Then, by reviewing the progress of development of Nigeria Ogun Guangdong Free Trade Zone, analyzing the Free Trade Zone aggregation degree by using the EG index, the results show that most industries have high agglomeration degree, and conform to the requirements of Nigeria to encourage pioneer industry. The third, through the analysis and discussion of the results, the article sums up the challenges faced by the Zone in terms of industry, infrastructure, the host country's political and economic environment. Finally, it puts forward some suggestions on the future optimization and development of the park from the government and the enterprise.
Accessibility is a key indicator connecting urban expansion and traffic infrastructure construction, which could reveal the potential development of metropolitan areas. The Conversion of Land Use and its Effects at Small regional extent (CLUE-S) and Auto-Logistic regression models were used to simulate urban expansion of the Guangzhou-Foshan metropolitan area in two scenarios, the regional development scenario and transportation planning scenario. Based on the evolution pattern of transportation accessibility and characteristics of urban expansion, the interaction between transportation accessibility and urban expansion was revealed. The results from the modified CLUE-S model showed better goodness of fit by adding accessibility indicators. The evolution patterns of the shortest space and time accessibility are all changing from a dual-core structure (1982) to a single-core structure—located within the Guangzhou City center during 1995-2020, especially the spatial pattern of the shortest time accessibility which is closely related to the main roads. Indexes of urban expansion intensity and expansion differentiation are increasing year by year. The city centers in the study area have almost been developed, with varying degrees of extension to Huadu, Panyu, Zengcheng, and other surroundings. Accessibility has an increasing negative impact on urban expansion. However, with traffic accessibility improved, the variation of accessibility has a declining positive effect on urban expansion; and the impact of urban expansion on variations of traffic accessibility is shifting from negative to positive effects. In the future, more attention should be given to improving land use efficiency and completing public service facilities around traffic stations.
The previous rural neighborhood is disintegrated from “diaspora” to “assembly”, making the resettlement community facing to enormous reconstruction pressure in social relation. Based on the connotation of public space vitality and by the AHP-fuzzy comprehensive evaluation method, the author constructed the model evaluating the community public space vitality of urban resettlement communities, conducted quantitative evaluation and comparison for the features of community public space vitality of the three resettlement modes by taking the 6 resettlement communities of Suzhou as examples and found: 1) There were obvious difference in the public space vitality of communities in different resettlement modes. Though the public space of nonlocal resettlement communities was consummated in facilities anddiversiform in types, the social vitality of the public space was the lowest of which the fundamental cause was that: most of the nonlocal resettlement communities were the assembled residential communities crossing villages and houses were distributed in lottery random mode, thus making the fragmentation degree of the social relation of nonlocal resettlement communities the highest. Such phenomenon meant that the social attribute behind the community public space was more important that its physical attribute for the improvement of public space vitality. 2) There was mismatch between the public space factors’ vitality degree and attention degree. Based on the match status between the public space factors’ vitality degree and attention degree, the author divided that public space to four categories—“high attention-low vitality”, “high attention-high vitality”, “low attention-high vitality” and “low attention-low vitality”. Based on the dialectical interactive logic of “the society-the space”, the author proposed the strategies creating the public space vitality of resettlement communities: 1) As for the future resettlement communities suiting the resettlement mode-“small assemblies inside villages plus large assemblies crossing villages”, we may minimize the fragmentation degree of community social relation in the process from “diaspora” to “assembly” by maintaining the population boundary of the previous “villages community” acquaintance society to the maximum extent in order to improve the public space vitality and abate the reconstruction pressure of community social relation. 2) As for the existing resettlement communities, we may divide the priority level of public space transformation based on the matching relation of public space factors’ vitality degree and attention degree, adopt differentiated transformation strategies to improve the public space vitality and the utilization efficiency of the transformation funds.
Based on the analytical framework of the adaptability of farmers toward rural tourism in traditional villages, this study constructs an adaptive evaluation index system, and takes 327 households of 6 traditional villages in Xiangxi Autonomous Prefecture, Hunan Province, as samples. Participatory rural appraisal (PRA) method is used to obtain data, and principal component analysis and cluster analysis are applied to analyzing the adaptability types, degree and influencing factors of farmer’s adaptability towards rural tourism in traditional villages. The results showed that: 1) The types of farmers' adaptability can be divided into 6 types: comprehensive adaptation, the cognition deficit, the ecological dominance, the policy deficit, the cultural dominant, and the lagging development, of which different types of characteristics are different. 2) The overall adaptability degree of comprehensive adaptation is relatively adaptive, and those of the other 5 farmers' adaptation are generally adaptive, but on the whole, the traditional village farmers in Xiangxi are adapting to the development of rural tourism. 3) Each adaptation type shows internal differences in the adaptability of the 6 factors that are policy, economy, culture, ecology, society and psychology, and other adaptation types in social, cultural and economic adaptability of the three factors are generally low except the farmers of comprehensive adaptation type. 4) The 13 impact factors of policy, social, ecological, economic and psychology factors, have obvious influences on the adaptability of farmers toward rural tourism, and the degree of influence are different. Finally, from the three aspects of farmers, communities and government, this article puts forward countermeasures and suggestions to improve the rural tourism adaptability of traditional village farmers.
With the carbon emissions rapid increased, the conflict developed among carbon emissions, economic development, and environmental protection. Liaoning Province is a typical province with high energy consumption, economic burden and environmental pollution. Therefore, the research has become a new breakthrough, which in alleviating the contradiction between the social economy and the environment. In this atricle, based on the three stage DEA model, we can calculate carbon emissions efficiency which is divided into technical efficiency, pure technical efficiency, and scale efficiency of 14 cities in Liaoning Province from 2004 to 2015. Then three coupling model was established to analyze the relationship among the carbon emissions, economic development, and environmental protection (3E system）. Meanwhile, GM(1.1) forecast model was also used to analyze the 3E system coupling in Liaoning province from 2016 to 2020, but the results are not optimistic. Based on the forecast results, it is necessary for Liaoning Province to take corresponding measures to solve these problems. The results show that the 3E system coupling in Liaoning Province is still at a low level. Of all the cities in Liaoning Province, Shenyang and Dalian have been leading all the time. In other twelve cities, Anshan, Fushun, Dandong, Jinzhou, Yingkou, Liaoyang, Panjin, Fuxin, Tieling, Huludao show moderate levels; while Benxi, Chaoyang have the lowest level. The coupling degree of 3E system has been promoted during these twelve years. However, the level of 3E system coupling is still low, which has a big margin for improvement. According to the conclusion, taking carbon emissions efficiency as the evaluation index of carbon emissions system is suitable, and the results are coincide with actual situation in Liaoning Province. In order to improve the coupling degree of 3E system and reduce regional differences, we believe that all the regions should unify their own actual development situation, compare superiority and make science formulation development policy. Overall, every city should take appropriate measures to promote region carbon emissions, economic development, and environmental protection.
This study analyses the spatial distribution characteristics of settlement sites, distributing in the West Liaohe River Basin and the neighboring Dalinghe River Basin, as well as the Luanhe River Basin between 9.5-2.3 ka B.P.. The settlement sites belong to a sequence of prehistoric culture, including Xiaohexi, Xinglongwa, Zhaobaogou, Fuhe, Hongshan, Xiaoheyan, Lower Xiajiadian and Upper Xiajiadian cultures. Based on the basic information of settlement sites, collected from the results of the national systematic archaeological field surveys, spatial distribution map of sites was drawn with GIS. Minimum distances from sites to rivers and altitudes were extracted with corresponding Box-whisker charts to present their statistical characteristics visually. Three main conclusions are concluded and deduced. Firstly, temperature, precipitation and vegetation changes caused by climate change influenced prehistoric culture development and subsistence strategies extensively. The drier and colder environmental condition since 6.0 ka B.P. promoted the development of primitive agriculture. The number of sites reached peak in Lower Xiajiadian culture which developed in a relatively warm and humid period. Temperature and precipitation dropped violently around 3.0 ka B.P., resulting that primitive agriculture was replaced by pasture. Secondly, prehistoric settlements depended largely on rivers, especially during dry and cold period. About 50% sites have the minimum site-river distances that are less than 6 km. Sites with the minimum distances of more than 6 km mainly distributed along gullies spreading to or from main rivers, especially in the area enclosed by the Laohahe River, the Jiaolaihe River and the Dalinghe River. Hydrological analysis and fieldwork prove: it is likely that these gullies were branches of rivers or seasonal rivers when it was warm and humid. Thirdly, settlements mainly distributed on the transition area (400-700 m) of plains and hills, which abounded in animal and plant resources. Settlements moved to lower altitude when it was colder and drier. Pasture, which was more resilient to hostile environment, made it possible for more Upper Xiajiadian settlements to distribute along rivers in higher mountainous areas.
There were many exceptional climate events all over the world in 1876-1878. Existing researches showed a huge controversy that the drought event in Northwest China based on different proxy data, such as historical documents and tree ring. To understand the spatial distribution of the drought event, this article collected the information of the climate and agriculture of the 1876-1878 from the historical documents in the Midwest Region of Northwest China in the late 19th century. The climatic information includes the event of the less precipitation and the event of the drought, and the agricultural information includes the event of the locust and the event of the poor harvest as well as famine. The historical documents are the central archives of the Qing dynasty and the local archives of the Xinjiang, and the local gazetteer of the Gansu, Ningxia and Xinjiang, and the collected works of the important person. Those events from historical documents were showed in the map. The result showed that event of less precipitation, drought, and locust appeared in the Midwest Region of Northwest China in 1876-1878. The historical documents suggested the spatial distribution of drought event and other related event in Gansu, Ningxia and eastern Xinjiang, and the most western distribution area was the middle of northern foot of Tianshan Mountains. And the most serious year of events was 1877. The drought events had less influence on the agriculture in the all area, and didn't lead to great famine in the Midwest Region of Northwest like North China.
The surface water and groundwater are very important for the farmland irrigation, industrial production and living water. Normally, there is transformation relationship between the surface water and groundwater. The mechanism of transformation relationship between surface water and shallow groundwater is a key factor role for the regional water cycle and the formation and management of water recourse. The Haihe River is an important river of the northern China. The water crisis caused by over exploitation for the groundwater has become the most important limiting factor for the development of the regional economy. This research based on the δ18O, δD and chemical data of different water samples of two sampling events were collected from the southern upstream of the Haihe River Basin (headstream of the Zhanghe River). We analyzed the hydrochemical and isotopic characteristic of groundwater and surface water during the two seasons by using the methods of study statistics, spatial interpolation analysis, Gibbs and Piper third-line graphs. Based on the two element mixed isotope hydrology separate model, we quantitative analysis the transformation relationship between groundwater and surface water for some sampling sites. The results shown that: 1) δ18O, δD and TDS of groundwater and surface river water samples of the headstream of Zhanghe River during wet season have significant variation. However, in the dry season, only the δ18O, δD and TDS of groundwater show the significant variation. 2) Whether wet season or dry season, the mainly water type are the Ca-HCO3·SO4 and the Ca-HCO3 for the shallow groundwater in the headstream of the Zhanghe River of upstream of the Haihe River Basin. The river water chemical type has significant season variation. The water type of river water were Ca-HCO3 changed to Na-Cl type during wet season, in wet season, due to the stronger evaporation, the river water chemical type were Ca.Na-Cl type. In wet season, the water type of river water and groundwater are similar and further indicate the conversion between the surface water and groundwater. There is obviously different between the water chemical type for precipitation, river water and groundwater during the dry season of headstream of the Zhanghe River. The results of Gibbs analysis shown, the groundwater and river water were controlled by the interaction between rock and water. 3) In dry season, the groundwater and river water have not significant interaction, however, the groundwater and river water shown strong transformation during wet season. About 10.95%-82.90% groundwater discharge from river water and the mean about 48.72%. Western headstream of the Haihe River shown larger interaction between groundwater and river water. The knowledge of these can promote effective management of water resources, and add new trace element data to the world water geochemistry.
Soil carbon sequestration and stability in coastal wetland are of great significance in maintaining primary productivity of wetland and mitigating global warming. Current studies about soil carbon stability mainly focused on the inland ecosystems while lack on the coastal wetland. Based on the content and active fractions of soil organic carbon, the responses of soil carbon fractions to varied salinity were analyzed. Meanwhile, three stabilization mechanisms of soil organic carbon were reviewed, and the game of soil carbon stability and main ions in salt was in depth explored. Furthermore, based on the study of carbon sequestration and stabilization of coastal wetland, three scientific issues have been suggested, including the interaction mechanism of soil carbon stabilization and nutrient cycling, and the relationship between soil carbon stability and microbial and enzymatic mechanisms, as well as the coupling research of multi-factor and multi-process, in order to understand the possible evolution trend of carbon sequestration, and for strategies making aiming at sustainable carbon sequestration in coastal wetland under the rising sea level, as well as to provide sound knowledge base for the development and improvement of carbon cycling theory in wetland soil of China.
Based on monthly precipitation data from 1960 to 2012, Standard Precipitation Index with 1 month time scale (SPI1) is calculated. We investigate the spatial and temporal variation characteristics of agriculture drought based SPI1 index and four growth stages of rice in the Southwest China. Results show that: 1) Overall, the drought station ratio for each year from 1960 to 2012 in the southwest is high and above 50%, presenting whole drought characteristic. 2) The temporal and spatial characteristics of agriculture drought during rice growth stage are different. ① From 1960 to 2012, GPR1 and GPR2 phases are dominated by whole drought. GPR3 and GPR4 phases show the distribution of the localized drought > regional drought >whole drought. ② The continuity drought characteristics during each growth stage of rice are evident. Especially in GPR2, it appears the whole drought and regional drought with the period of 2-6 years. ③ The area with high drought occurrence frequency for three type of drought has shown spatial shift characteristic during different growth stage. The area with high occurring probability of mild drought has transfer from northeast to southwest trend. The region with high occurring probability of moderate drought transferred from the north to the south. The region with high occurring probability of severe drought the spatial distribution of each stage is quite different. ④ In the GPR1 and GPR2 phases, rice is mainly affected by mild drought and moderate drought. In GPR3 and GPR4, severe drought occurrence frequency increases.
This article makes End Member analysis on grain-size data collected from high resolution 125 samples based on typical Late Pleistocene-Holocene Loess-Paleosol profile (CCY profile) in Changchengyuan, Ningxia Province, and do the wavelet analysis for the End Members components on the axis in depth. The research result shows that four End Members can be separated from the sediment grain sizes in CCY profile. And the EM1 may indicate dust from far source under the high-altitude airflow controlled by westerly belt. The EM2 may indicate dynamic strength of sedimentation under the influence of weathering and pedogenesis. The EM3 may represents the eluviation dynamic characteristic. The EM4 may indicates the northwest monsoons typical eolian loess under the influence of component characteristics. According to the wavelet analysis, it can be concluded that the component content of each dynamic of End Member has periodic variation at different depths, which indicates that the corresponding time scale of the paleomonsoon variation has periodic characteristics, and also indicates that the sedimentary profile has been in a continuous and uninterrupted sedimentary state, and the sedimentary dynamic processes are recorded completely. Each End Member component has different periodic characteristics on different depth (time) scales.
