Based on the national dynamic monitoring data of the floating population in 2017, using the binary logistic regression model and SUEST inspection, this paper makes an empirical study and further analysis of the influencing factors on the Hukou transfer intention of the rural-urban and urban-urban floating population and draws the following conclusions: 1) In general, the Hukou transfer intention of urban-urban floating population is significantly higher than that of the rural-urban floating population. The household register value and social assimilation have significant impacts on the Hukou transfer intention of the two types of floating population, but the degree of influence is different between the two. 2) In comparison, the household register value of the outflow place significantly hinders the Hukou transfer intention of rural-urban migrants, and has a weak influence on the Hukou transfer intention of urban-urban migrants. The household register value of the destination and social assimilation have a more significant impact on the Hukou transfer intention of urban-urban floating population. 3) The impact of household registration value and social assimilation on the floating population’s Hukou transfer intention is different in cities and the distance of migration. 4) The root cause of these differences are the differences in values and behavior patterns shaped by different household registration identities.
Based on the research of HBase storage mechanism, this article aims at the low efficiency of existing storage query methods, the HBase spatial data storage table patterns such as row key, filter column family, geometric column family and non-geometric column family are designed, and the original region query method is improved based on MapReduce algorithm, the above improvements effectively improve the query efficiency of vector spatial data in HBase. The experiment was carried out with the data of geological hazards in recent 100 years. The results show that the storage model designed in this article is feasible, and the query algorithm is more efficient than the traditional query algorithm. Due to the communication in the process of MapReduce, when the amount of data is less than 50 000 byte, the advantages of this algorithm are not obvious; When the amount of data is more than 100 000 byte, the query time of this algorithm is less than 1/2 of the original; The query time of the algorithm is only 1/20th of that before the improvement of the algorithm when the amount of data reaches 1 million byte. The greater the amount of data, the more obvious the advantages of parallel processing.
Identifying the spatial conflicts and formulating scientific plans are the key to achieving land and sea coordination. Based on the current situation and planning of land and sea space utilization, this paper constructs a theoretical analysis framework of the spatial conflict, applies conflict identification matrix, neighborhood conflict measurement model and social network analysis, quantitatively identifies the current situation conflict and planning conflict between land and sea based on the two directions of land to sea and sea to land, and classify the conflict zones by the four quadrant model. Taking Laizhou City in Shandong Province as study area, this paper takes 1 km grid as the research unit, focusing on the interaction zone coastline surrounding 2.5 km. The main results are as follows: 1) From the perspective of the scope and intensity of conflict, the land use and planning of Laizhou has a larger area beyond the coastline, and the land and sea interaction conflict area will continue to increase. Land and sea coordination should pay attention to the combined spatial utilization and cross-system interaction. 2) From the perspective of conflict types, two types of utilization modes have a great impact, including waters and wetlands of land and marine fishery sea. In the planning conflict, four types of functional areas have a great impact, including general agricultural areas and other areas of the land, marine agricultural and fishery areas and port shipping areas. 3) The coupling zoning results of reality and planning show that relatively independent land and sea spatial planning has a certain effect on controlling and mitigating spatial conflicts. However, as the overall utilization and management of land and sea space is imminent, it is very important to optimize the system according to the characteristics of different zoning.
Based on the statistical data from 2006 to 2016 and taking 11 coastal areas (due to the data limitation, Hong Kong, Macao and Taiwan of China are excluded in this study) of China as examples, the paper constructed the evaluation index system of China’s marine ecological security, evaluated the spatial-temporal differentiation of China’s marine ecological security, and analyzed the shift of the center of gravity of China’s marine ecological security pattern based on the standard deviation ellipse. Finally, using the Hurst index to study the evolution trend of marine ecological security in China. The results showed that from 2006 to 2016, the status of marine ecological security in China showed an overall upward trend. The average value of marine ecological security index increased year by year, from 0.346 2 to 0.421 0, with an increasing rate of 21.6%. The overall marine ecological security in China has phases. The regional differences of marine ecological security in China are increasing year by year. In terms of spatial pattern, the overall status of marine ecological security in China is good. It roughly presents the spatial distribution characteristics of “north-south symmetry with the center of Shanghai”. The change range of marine ecological security center of gravity in China is minor, and it basically shifts from north to south around 31°10′N, showing a north-south shift with Shanghai as the center of gravity, and the trend of northward shift is relatively obvious than southward . In terms of the evolutionary trend, the marine ecological security in China is dominated by very weak anti-persistence, and the Hurst index is generally located at the level of ?2-2, with a relatively small overall change range. The evolution trend presents spatial imbalance.
This study uses mobile phone data and point of interest data to discover the relationship between the scope of elderly’s life circle and various public service facilities configuration by looking at Beijing as a case. The results of analysis show that, firstly, the elderly’s life circle has a feature of spatial stratification, which including the neighborhood life circle, residential life circle, urban life circle. Secondly, there is a scale effect on the relationship between the radius of life circle and accessibility of public service facilities, and the intensity of the matching relationship between the spatial radius of residential life circles and the accessibility of public service facilities is significantly higher than that of neighborhood life circles. Thirdly, there are differences among different facilities. The accessibility level of rigid demand facilities such as shopping, leisure and entertainment, and medical service facilities for the elderly is negatively correlated with the radius of the life circle, while the accessibility of recreational and entertainment facilities such as catering, cultural and educational facilities is vice versa. Fourthly, there are also significant differences among different geographical locations. The impact of facility accessibility on the radius of life circle is much weaker in the downtown area than in other areas, but the influence is stronger in the suburbs. The findings and conclusions would provide new evidence for the practice of national spatial planning and elderly-livable urban construction.
China’s overseas economic and trade cooperation zones are the spatial diffusion of the development experience of China’s special economic zones. Based on the unique conditions of host country, the construction experience of domestic parks should be adjusted and applied to China’s overseas economic and trade cooperation zones in order to adapt to the localized development. By use of case study and comparative analysis, this paper proposes a theoretical framework of policy mobility, and takes Tianjin Economic-Technological Development Area (TEDA) and China-Egypt TEDA Suez Economic & Trade Cooperation Zone (TEDA Suez) as examples to compare the relevant policies of domestic industrial zone and overseas economic & trade cooperation zone, thus verifies the applicability of policy in different “soil environment”. The research shows that: 1) According to the influencing factors of policy implementation and different functions of policy, policy mobility can be divided into policy transplantation, policy adjustment and policy innovation. 2) Planning and construction experience, operation management experience, environmental protection policy, talent training policy can be used directly as policy transplantation; the development model and cultural policy belong to policy adjustments; legal policy, promotion policy and preferential policy should be completely changed as policy innovation. 3) The common features of two parks are reflected in the use of mature experience in domestic parks, the cultivation and reserve of talents, the protection of the park’s ecological environment, and the improvement of infrastructure and supporting facilities. 4) The individuality of parks is embodied in seeking for the similarities on the basis of respecting cultural differences, the building of park brand, the innovation of promotion system, the establishment of coordination mechanism. This paper applies the theory of policy mobility to studying the relationship between domestic and overseas parks, and exploring the process of policy transplantation, policy adjustment and policy innovation, which deepens the connotation of policy mobility theory and enriches the theoretical research of overseas economic and trade cooperation zone.
Since the beginning of the 21st century, inter-city cooperative zones have become an essential mode for China’s central and local governments to balance regional development and promote inter-city cooperation along with their pilot reforms and gradual spread, effectively improving the efficiency of regional allocation of resources. Inter-city cooperative zones combine the production organizing model of ‘Enclave Parks’ abroad and China’s institutional experiences in building ‘Special Economic Zones’ and present a new spatial production strategy of China’s Experimental Regionalism. The pilot construction and gradual spread of inter-city cooperative zones in most areas of China have resulted in the significant restructuring of regional urban networks and local urban spaces. Based on institutionalism in the evolution of urban spaces, this paper examines the institutional evolution for developing inter-city cooperative zones in the Yangtze River Delta. It conducts empirical studies on the case of the Wuxi-Xinyi (Xiyi) High Tech Zone to discuss the basic trajectory and changing institutional logic of the three transitions of inter-city cooperative zones. The paper has reached the following conclusions. 1) Firstly, 3 institutional space modes are manifested in the development of inter-city cooperative zones, namely, the embedded, expansive and reconstructive mode, which significantly influences the urban expansion and industrial restructuring of inter-city cooperative zones. In addition, the transitions of zones and the restructuring of institutional space are mutually influenced in the dynamic process of interleaving evolution. 2) Secondly, the new institutional organization in the inter-city cooperative zones depends on the authorities’cooperating network. In such a new institutional organization, core actors tend to perform formal institutional arrangements to pursue their best interests and promote local development; institutional rules are set up for participants to regulate different capital activities. Besides, local governments promote spatial restructuring by establishing institutional organizations and institutional rules through joint action. 3) Finally, after analyzing the restructuring process of the Xiyi Inter-city Cooperative Zone, this study summarizes the dynamic mechanism and law of the spatial evolution of intercity cooperation zones. We find that the alternating evolution of institutional space and economic space, the periodic fluctuation of the authorities’cooperating network, and the different stratification of space strategies are the fundamental laws to promote the transition and development of zones.
Based on the panel data of 285 cities in China from 2000 to 2019, this paper searches the number of patent applications related to artificial intelligence with keywords. Using standard deviation ellipse, exploratory spatial data analysis and spatial Dubin decomposition model, this paper analyzes the temporal and spatial evolution characteristics and influencing factors of urban artificial intelligence in China. The results show that: 1) The development of artificial intelligence can be divided into initial stage, growth stage and high-speed development stage. There is an obvious hierarchical effect in space. The advantages of eastern coastal cities are obvious, and the rise of central and western cities are accelerated. 2) Artificial intelligence has a strong spatial positive correlation, and cities in some areas form an agglomeration development trend. The spatial distribution produces polarization along the “northeast-southwest” and diffusion along the “northwest-southeast” direction. The distribution center is located in Anhui Province, with a trend of continuous migration to the southeast. 3) The improvement of marketization level, population density, human capital, foreign investment level and financial development level are conducive to the development of artificial intelligence, and there is a positive spatial spillover effect. The relationship between government intervention and the development of artificial intelligence shows an inverted U-shaped curve, with spatial spillover effect. Industrial upgrading and infrastructure construction are conducive to the development of artificial intelligence, but the spatial spillover effect are not obvious. The research conclusion can provide empirical enlightenment for China’s cities to accelerate the implementation of artificial intelligence strategy.
Market-oriented watershed payment for ecosystem services (PES) is an important pathway to promote the realization of ecological product value and is a typical practice of payment for ecosystem services all over the world. Research on the mechanism of watershed PES is in line with the significant need for National Ecological Civilization Construction in China. Therefore, based on identifying the concept, content, and characteristics of watershed PES, this article analyzes and summarizes typical types and patterns of watershed PES worldwide. In addition, the article reviews watershed PES research progress in 4 aspects, including market subjects and target ecosystem services (ES), payment level and standards, mechanism designing, and effectiveness evaluation. Furthermore, in order to provide scientific support and evidence for decision-makers to realize ecological product value, possible trends and directions of future research are suggested. Firstly, there remains an urgent need to conduct more research regarding watershed ecological environment monitoring and quantitative ES indicators. Secondly, comprehensive valuation assessments based on the full-chained ES supply and demand are also needed for further study. Finally, research on mechanism designing for multi-objectives and long-term performance evaluation of PES programs should be enhanced in the future.
It is of great significance to study the temporal and spatial variation characteristics of ecosystem services value (ESV) and the trade-offs and synergies among various services to realize the coordinated development of regional ecology and economy. Based on the revised equivalent factor table and combined with the land use data of 7 periods from 1988 to 2020, the study of spatio-temporal evolution characteristics of ecosystem services value (ESV) in the peripheral region of the Poyang Lake is explored by data processing and spatial analysis of GIS technology. At the same time, the ecosystem service trade-offs and synergies model is introduced to analyze the trade-offs and synergies of seven ecosystem service functions. The results show that: 1) From 1988 to 2020, the ecosystem service value in the peripheral region of the Poyang Lake increased from 57.79 billion yuan to 59.25 billion yuan, showing the fluctuation characteristics of first increasing, then decreasing and then increasing. During the whole study period, ESV of water area is the largest, followed by woodland and arable land. The main contributing factors of ESV change are water area, grassland and woodland. From the perspective of single ecological service value, the regulation service value is the largest during the study period, accounting for more than 77% of the total ESV. 2) The spatial distribution characteristics of ecosystem service value in the study area are closely related to land use types. In recent 32 years, the spatial distribution of ecological service value in the study area has shown obvious imbalance. The area with the highest ecological service value is the area with abundant water resources, and the area with the lowest ecological service value is the contiguous area with concentrated construction land. ESV significantly decreased in areas with the greatest intensity of construction land expansion, including Nanchang urban area, Jiujiang urban area, and urban built-up areas of other districts and counties. The areas with increased ESV are evenly distributed in the northeast and northwest of the study area, as well as the southeast and southwest near the outside of the study area. 3) In the study period, the synergistic relationship is the dominant relationship among ecosystem services, while the number of the trade-off’s relationship is small and mainly existed between food production and other services. The results indicate that there is conflict between food production and environmental protection, and there is competition between cultivated land and other land use patterns in the study area. During 1988-1999 and 1999-2009, the other six ecosystem services showed synergistic relationship except for food production service. From 2009 to 2020, the degree and direction of interaction among ecosystem services have changed, and the maximum value of trade-offs and synergies have increased. The trade-offs and synergies between ecosystem services has a profound impact on the balanced development of regional ecological environment protection and economy. Moreover, trade-offs and synergies play an important role in coordinating multiple goals, maximizing human well-being and supporting the sustainable use of social-ecosystems. The research results can provide reference information for promoting the coordinated development of ecological environment protection and economy in the peripheral region of Poyang Lake.
Tourism informal employment is an important part of the tourism employment system, which has become an important driving force to promote urban tourism economic growth. However, tourism informal employment could also generate some negative impacts on city management and the order of urban tourism market. To maximize the positive effect of tourism informal employment and to manage it effectively, it is necessary to figure out the scale and current situation of informal employment in the development of urban tourism. However, due to the characteristics of large fluidity, instability and concealment, the measurement of tourism informal employment has become a hard nut to crack for academia. Beijing, as a well-known city tourist destination, has attracted a large number of informal tourism employees along with the rapid development of urban tourism. Due to historical and socio-economic reasons, Beijing’s tourism informal employment has many problems to be solved. Therefore, taking ten typical scenic spots of Beijing as an example, this study investigated the group characteristics of informal employees in urban tourism, and innovatively introduced the capture-mark-recapture (CMR) approach, which was originally used to measure the population number of wild animals, into the scale measurement of informal employees in urban tourism. To ensure the effectiveness and feasibility of this method, the reliability and validity of the CMR and its statistical formula are evaluated by Monte Carlo Simulation with SAS software as a statistical analysis tool. The conclusions are as follows: 1) the human capital of informal employees in urban tourism scenic spots is relatively low, most of which are young and middle-aged women. They mainly work as souvenir (local specialty) traders and tour guides, most of which are from the nearby region, North China. 2) The overall scale of tourism informal employees in the ten typical scenic spots of Beijing is small (1126), compared with the overall number of employees in the tourism industry of Beijing. The urban tourism informal employees were widely distributed in the city, though. 3) CMR approach can effectively measure the scale of tourism informal employment population, which is scientific and reliable. Academically, by introducing the CMR approach into the scale measurement of tourism informal employees, this study effectively fills out the deficiency of measurement methods in this field. Practically, this study could provide scientific reference for the Beijing tourism authorities in terms of the measurement and management of tourism informal employment.
COVID-19 pandemic has substantially impacted the domestic tourist source market demand in tourism destinations. Exploring the spatially differentiated characteristics and mechanisms of these impacts can provide insights into destination resilience's theoretical and practical implications. The study takes the Confucius Temple scenic area in Nanjing as the research case and analyzes the impact on its 309 domestic tourist source cities (at prefecture-level and above) under the major public health events. The study uses methods such as Geographic Concentration Index, Attractive Radius Index, and exploratory time-space data analysis to explore the spatio-temporal change in the tourist source market after the pandemic. We construct the Loss Index to quantitatively evaluate the impact, spatial difference, and the pattern of the pandemic on tourist source market demand with the bivariate spatial autocorrelation method. The results show that: 1) after the pandemic, the spatial clustering characteristics of the source market and the trend of proximity travel are more obvious; the degree of damage to the source demand is differentiated in space; the source market for medium- and long-distance tourist source market shows higher vulnerability. 2) The impact of the pandemic on the scale of the tourist source market is greater than the spatial pattern; the evolution of the spatial pattern of the tourist market in pre-and post- pandemic has strong consistency and positive spatial integration, with a stable local structure and a low probability of spatial-time transition. 3) There are obvious differences in spatial correlation characteristics between short-haul sources within 250 km and medium-haul sources within 900 km. This paper provides a more refined quantitative assessment of the extent of damage and its spatial differentiation across tourist source markets in the aftermath of the pandemic. This study further enriches the theoretical research results on the impact of crisis events on the source markets of neighborhood-based scenic destinations. Also, it guides destinations in developing recovery strategies for different source markets.
The key photosynthetic parameter of maximum carboxylation rate (Vcmax25) in Dynamic Land Surface Model (DLM) was parameterized at monthly and yearly time scales, respectively, for 15 flux towers (60 site-years data) including nine vegetation functional types (PFTs) by using variable-controlling iteration method. The GPP simulation results of the two parameterization schemes are compared and analyzed by using the observation data of the remaining station years not involved in parameterization. The results indicate that: 1) the Vcmax25 varied seasonally obviously for all PFTs. Specifically, the variation of Vcmax25 was largest in winter and least in summer. The fluctuation of Vcmax25 was similar among different biomes and was nearly twice in boreal climate region as much as that in temperate climate region. 2) The accuracy of GPP estimation using the seasonal parameterization scheme of Vcmax25 was obviously improved, among which the forest and shrub increased the most significantly in winter (R2 increased by 35.7%, RMSE decreased by 23.24%), followed by spring and autumn, and the least in summer. Even with seasonal fluctuation of parameter considered, DLM-FvCB still difficult well capture the GPP variations for C3 grassland. This study suggests an important consideration of temporal parameterization in further improvement of modelling GPP in land-surface model.
Since the 21st Century, the rapid development of the Chinese economy has sped up the transformation and reconfiguration of the urban-rural spatial structure and industrial structure. Land urbanization raises several issues caused by urban expansion, such as inefficient land use, uncontrollable construction areas, abandoned rural settlements, etc. Meanwhile, it further leads to cultivated land changing to non-agriculturalization, non-food, and marginalization due to urban agglomeration along with urbanization such as the population, capital, and industry. Cultivated land, as one of the most variable land use types, is an essential support for rural development. It is conducive to realizing the utilization of cultivated land, developing sustainable land management, and promoting sustainable region development to explore the spatial-temporal evolution and its influencing factors of cultivated land functions. Taking the 24 counties in the Dongting Lake area of Hunan Province as an example, the study analyzed the spatial-temporal evolution, spatial divergence, and influencing factors of cultivated land functions from economic production, social security, and ecological maintenance by using the entropy and geodetector method. Results show that 1) the economic production function of cultivated land showed a general upward trend from 1998 to 2018 and distributed in the central and southwestern Dongting Lake area with better agricultural development. The social security function has improved significantly, showing a decline in three regions (Linli, Jinshi, and Dingcheng). The spatial pattern of ecological maintenance functions is changing slightly, with the high in the central and low on both sides. 2) Natural geographical conditions are conducive to cultivated land function at an early stage, weakening over time gradually. Socio-economic factors on the spatial differentiation of cultivated land functions increase with the development of the social economy. The ability increases as it improves to impact the spatial differentiation of cultivated land functions. The interaction among multiple factors can significantly enhance cultivated land's spatial differentiation and promote diversified development.
Based on the perspective of coupled social-ecological system, scientific measurement of ecosystem service trade offs and synergies plays a vital role in regional sustainable development, ecological security, and human well-being. In order to promote the sustainable development of ecosystem services in nature reserves and improve human well-being, taking Potatso National Park as the research area, this article measures the spatial characteristics of its social value (aesthetic value, cultural value, recreation value) and ecological value (habitat quality, carbon storage, water yield ) with the help of SolVES model and InVEST model. Then the spatial trade-off and synergy relationship between social value and ecological value of Potatso National Park is deeply analyzed using bivariate spatial autocorrelation method. The results show that: 1) The hotspots of social value exhibit a ‘multi-core and multi-strip’ spatial pattern, with an 8.6 of social value index (the index is between 1-10), and the closer it is to the water body, the greater its contribution to social value (the contribution is 45.9%). 2) Relatively high and high spatial range of ecological value accounts for half of the park area (49.91%), mainly located in Bitahai Lake area and Zano area in the northeast of Niru with well-preserved virgin forest. 3) There is a significant spatial dependence between social value and ecological value, among which the areas with low social value and high ecological value are the main spatial aggregation characteristics of the park. This study provides a scientific basis for sustainable management decision-making of ecosystem services and help to improve the theoretical framework of social-ecological system based on ecosystem services.
In the context of global climate change, habitat adaptation studies of the karst tiankeng plants are gradually being highlighting. However, it is unclear what ecological strategies plants adopt to acclimate to tiankeng microhabitat, and how plant life history, genetic history, and ecological factors contribute to functional trait variation. Therefore, we analyzed the degree of variation of 8 functional traits from 34 woody species in a typical moderate-degraded Shenxiantang Tiankeng of Zhanyi Nature Reserve of Yunnan Province. The relationship between functional trait variation and family group, life type, growth type and ecological factors and the explanatory effect of soil factors on plant trait variation were further explored at intraspecific and interaspecific levels. Our results showed that the characteristics of woody species from tiankeng underground forest were large leaf thickness, small specific leaf area and large leaf dry matter content. Interspecific variation of plant traits in shrubs was generally smaller than that of trees, and the degree of variation of plant traits did not significantly difference between evergreen and deciduous tree species. The majority of intraspecific and interspecific variation of leaf traits was greater than that of branchlet traits. The average intraspecific variation coefficient of plant traits in the Shenxiantang Tiankeng amounted to 23.45%, which was lower compared to the vegetation types in other non-karst regions. It indicated that plants had less shape plasticity under the karst tiankeng regions. Soil nutrients were the dominant environmental factor which determined the variability of community traits at the sample site scale. Moreover, the phylogenetic history of species and their life history characteristics were also internal drivers of functional trait variation in this zonal vegetation. In conclusion, during the long-term evolution of species, the functional traits and their degree of variability were influenced by a combination of non-biological environmental factors, phylogenetic processes, and life history strategies. This study aims to provide materials and evidence for the value of species refuges in karst tiankengs with negative topography, and to contribute scientific support for enhancing the ecosystem service functions of karst ecologically vulnerable areas and nature reserves in Yunnan Plateau, and for scientifically undertaking ecological restoration of tiankeng external areas and zonal vegetation.
In this study, we explored the effects of salinity on microbial residues (represented by amino sugar) and the contribution of microbial residues to soil organic carbon (SOC) pool under coastal wetlands in the Yellow River Delta. In addition, we examined how soil physicochemical properties influence microbial residues contribution to SOC. Generalized linear models were used to assess the relationships among microbial residues contribution to SOC, the ratio of fungal residues to bacterial residues, and soil physicochemical properties. The gradually increased soil salinity resulted in the decline in amino sugars, microbial residues (including fungal and bacterial residues) and the contribution of microbial residues to SOC, which indicated that coastal wetlands with high salinity restrain microbial residues retention in SOC pool. The ratio of fungal residues to bacterial residues was decreased across increased soil salinity, implying that fungi was sensitive to salinity stress, and bacteria had stronger tolerance to salinity stress. Linear regression analyses showed that soil water content, SOC, soil N, Caexe and fungal residues/bacterial residues were positively related with microbial residues contribution to SOC. The fine soil condition (e.g. high water level, SOC and N contents) increased the accumulation of microbial residues, promoting SOC storage of coastal wetlands with low salinity concentration. However, high salinity stress greatly decreased the contribution of microbial residues to SOC, which was associated with low available C substrate in coastal wetlands with high salinity concentration. Additionally, increased salinity induced the decline in the contribution of fungal residues to SOC, but did not change the contribution of bacterial residues to SOC. These findings indicated changed fungal residues would substantially influence SOC storage. In this study, we found that low salinity soils had higher microbial residues and its contribution to SOC, while high salinity stress reduced microbial residues and its contribution to SOC under coastal wetlands in the Yellow River Delta. Our study elucidates microbial contribution to SOC pool through residues reservoir in coastal wetlands, and push microbial metabolites to a new application in wetland SOC cycling.
Soil microbial community is an important bioactive component of soil ecosystems. Its structural and functional diversity directly affects nutrient processes. The microbial functional diversity varied with micro-ecological environment of soil in different reclamation time. This study aimed to investigate the variations in the functional diversity of soil microbial communities in farmland of black soil with different reclamation time We selected three typical black soil of reclamated for 98 years, 50 years and 10 years, located in the Heilongjiang Province. Experiments were performed in three typical black soil reclaimed for 98 years, 50 years and 10 years, which is located in the Nenjiang Plain of Heilongjiang Province, and samples were collected from 3 layers of soil (0-10 cm, 10-20 cm, 20-30 cm) in July 2019. The experiments were performed by selecting the different soil layers (0-10 cm, 10-20 cm, 20-30 cm) of various reclamation time in July 2019. Biolog-Eco microplate technology was used to analyze microbial activity, functional diversity and utilization of various carbon sources. The results showed that soil microbial activity of farmland reclaimed 98 years was the highest. Order of soil microbial community composition and functional diversity index were as follows, farmland reclaimed for 98 years > 10 years > 50 years. Carbon utilization capacity of soil microorganisms in black soil farmland was affected by reclamation time and soil depth. In the 0-10 cm layer, soil microorganisms had the highest utilization of carbon source. Principal component analysis showed that the microorganisms in reclaimed soil mainly used carbohydrates and amino acids. Reclamation time had significant effect on the activity and functional diversity of soil microbial community in black soil. The changing pattern of soil microbial functional diversity effected by reclamation time was similar to that of soil organic matter content. These results provide a reference for further exploring the relationship between reclamation time and soil microbes functional diversity while maintaining and restoring soil fertility, rational exploitation and sustainable utilization of black soil resources.
