The integration of ports in the Yangtze River Delta is an inevitable trend of regional integration. Promoting the integration of ports in the Yangtze River Delta can enhance the international competitiveness of the port group in the Yangtze River Delta. In order to analyze the integration of ports in the Yangtze River Delta from the perspective of the maritime producer services, this paper uses the data of Lloyd’s maritime directory from 2006 to 2018, as well as the Talor “Interlocking Network Model” and community structure to analyze the spatial-temporal pattern of low-end, mid-end and high-end maritime producer services and the spatial connection of port cities in the Yangtze River Delta. The results show that: (1) The three types of maritime producer services in the Yangtze River Delta showed rapid but uneven development. The low-end maritime producer services are still the development focus, but it has begun to transform to the high-end maritime producer services. (2) The low-end maritime producer services present a distribution pattern of “along the river and along the coast” with Shanghai as the center, and the mid and high-end maritime producer services form an obvious port hierarchy. (3) The cooperation pattern has begun to take shape in the Yangtze River Delta. The port cooperation in the mid-end maritime producer services is the closest and the degree of integration is the highest. The degree of closeness of collaboration or degree of integration, from high to low, are: mid-end, high-end, and low-end. (4) Jiangsu and Zhejiang have formed obvious community structure respectively, which has intensified the competition among the provinces. The integration degree of port cities is limited by the provincial administrative divisions, and has not yet broken through the administrative barriers. How to break the administrative barriers between the provinces has become the key to promoting the high-quality integration of the ports in the Yangtze River Delta. Furthermore, Shanghai’s “siphon effect” in high-end maritime producer services is obvious. Ports of different grades should complement each other, form dislocation competition, and promote the integrated development of ports in the Yangtze River Delta with higher quality.

 This paper uses the DEA-Malmquist method to measure the green innovation performance of the Yangtze River Delta Urban Agglomerations from 2012 to 2018, and uses Tobit regression analysis to analyze the factors affecting the green innovation performance of the study area. The empirical results show that: (1) From the green innovation performance scores, the green innovation efficiency of cities in the Yangtze River Delta Urban Agglomerations is uneven, and the gap is obvious; the overall green innovation efficiency has been improved, that is, new knowledge and technology have promoted the development of green economy, but the effect is not obvious; The contribution of the total factor growth rate mainly comes from the improvement of the level of technological progress, indicating that technological progress is still the main means to improve the performance of regional green innovation. The dynamic development of green innovation performance from 2012 to 2018 further confirms the importance of enhancing technological progress; In the process of urban development, there is a poor coordination between the pursuit of technological progress and the utilization of technology under the existing resource endowment. (2) The spatial differentiation of green innovation performance among cities in the urban agglomeration is obvious, with “high in the east and low in the west” as a whole. Certain spatial agglomeration, forming a “Z”-shaped spatial distribution characteristic; Jiangsu Province has a more outstanding overall performance level, and most cities in Anhui Province have poor green innovation performance. (3) The regression analysis on the influencing factors of green innovation capability shows that the industrial structure has a significant impact on the efficiency of green innovation. Enhancing the accessibility of information between regions can improve the level of innovation performance.

Under the background of green development, the way to make appropriate use of environmental regulation tools to deal with the relationship between tourism industry development and ecological environment protection is a hot issue in current research.By constructing the evaluation index system of regional environmental regulation and tourism ecological efficiency, using entropy weighting method and super efficiency SBM model, this paper calculates the value of environmental regulation and tourism ecological efficiency of urban agglomeration in the Yangtze River Delta from 2007 to 2017. On this basis, based on the natural breakpoint method, this paper analyzes the spatial pattern evolution of the two, then establishes a panel model, and uses the system generalized moment estimation to analyze the impact of environmental regulation on tourism ecological efficiency from the two dimensions of time and space.The conclusions are as follows:（1)The overall environmental governance of urban agglomerations has been strengthened, and the regional differences have gradually narrowed. From the perspective of spatial distribution, the spatial pattern changes greatly, which is reflected in the transfer and upgrading of high regulatory intensity areas from the central to the eastern and western marginal areas;（2)The overall level of tourism ecological efficiency of urban agglomerations is not high, showing a trend of first falling and then rising, and the spatial differences first expand and then narrow. Efficiency gradually forms the spatial distribution pattern of high-efficiency cluster cluster in the central of urban agglomeration;（3)There is a significant negative correlation between environmental regulation and tourism ecological efficiency in urban agglomeration, but with the increase of lag order, the negative impact of environmental regulation on green development of tourism industry is gradually weakening. From the spatial dimension, there are significant differences in the impact of urban environmental regulations on efficiency. Among them, the cities which are positively affected by environmental regulations are less and mainly distributed in the central area of urban agglomeration.

Under the background of “double circulation”, it is an inevitable choice to put the foothold of development in China and actively expand domestic demand by relying on the domestic market. By constructing the index system of consumption center city, this paper explores the temporal and spatial evolution of consumption center city and its influencing factors by using standard deviation ellipse, Moran index and GWR model. The results show that: (1) Shanghai has always been the only regional consumption center city in the Yangtze River Economic Belt, with absolute leading advantages; Most of the provincial consumption center cities are concentrated in the important economic center cities of the Yangtze River Delta and some provincial capital cities; (2) The overall consumption center cities in the Yangtze River Economic Belt present a “southwest-northeast” spatial distribution pattern, and constantly gather in the east (north) direction. The upstream shows a “southwest-northeast” distribution pattern, while the middle and lower reaches show an opposite direction, showing a “southeast-northwest” distribution pattern; (3) In 2000, 2010 and 2018, the consumption center cities in the Yangtze River Economic Belt showed obvious spatial agglomeration, and the agglomeration gradually strengthened; (4) The proportion of tertiary industry, economic development level, population mobility, the development of financial industry and government support are all conducive to promoting the development of consumption center cities, among which the proportion of tertiary industry and the development of financial industry have obvious pulling effect on regional consumption center cities and provincial consumption center cities, but the income ratio between urban and rural areas is negatively correlated with that of consumption center cities, which has an inhibitory effect on the development of consumption center cities. This paper studies the spatial and temporal distribution pattern and driving factors of consumption center cities, hoping to provide certain reference value for the development of consumption center cities in the Yangtze River Economic Belt.

Knowledge intensive service industry is an important part of China’s modern independent innovation system. This paper explores the dynamic evolution trend of spatial agglomeration of knowledge-intensive services in prefecture-level and above cities in China by constructing a comprehensive measurement model, and reveals the driving factors of spatial agglomeration of knowledge-intensive services by using geographically weighted regression model. The results show that:(1) The overall degree of knowledge-intensive service industry agglomeration in China is low, the industrial agglomeration is not sufficient, the regional agglomeration is not balanced, and the agglomeration trend of different subsectors is obviously different. The spatial agglomeration trend is gradually developing towards the eastern coastal region as the center, and the central and western regions as the periphery; (2) The agglomeration of knowledge-intensive service industry has obvious positive spatial autocorrelation, and the agglomeration of knowledge-intensive service industry in the neighboring area has strong mutual driving effect; (3) the system of urbanization level, research and development strength, environmental factors, the stock of knowledge, on the whole, are an important force in driving knowledge intensive service industries agglomeration, based on the analysis of the spatial heterogeneity, knowledge-intensive service industry spatial agglomeration driving factors on the varied impact of different areas, on the whole present obvious ladder distribution characteristics, The spatial distribution characteristics of the elasticity coefficients of variables in adjacent provincial capitals or municipalities are significant, and the spatial spillover effect of agglomeration driving factors is obvious.

Jiangsu section of the Grand Canal is not only a key area for the cultural protection and inheritance of the Grand Canal, but also a red river to witness the revolutionary history of our Party and conserve national spirit. On the occasion of the 100th anniversary of the founding of the Communist Party of China, this study takes the core area of Jiangsu section of the Grand Canal as the research subject. Based on tourism network data, this paper constructs an evaluation model of the network heat of scenic spots, and uses the methods of trend surface, kernel density, GIS analysis technology to explore the spatial-temporal evolution characteristics of the network heat of red tourism. The research results show as follows. (1) In terms of time evolution, the popularity of the red tourism network in Jiangsu section of the Grand Canal shows an evolutionary path of steady rise. The seasonal network heat shows a fluctuating trend of “three peaks and four valleys”, and the seasonal change of red theme heat is affected by the occurrence time of red events. (2) In terms of spatial evolution characteristics, the core of the red tourism network in Jiangsu section of the Grand Canal has evolved from “single core” to “three cores”, and the radiation of the high-density area of the red tourism network to the surrounding areas is increasing. In Southern Jiangsu-Northern Jiangsu-Central Jiangsu, the heat degree shows a decreasing trend. The degree of homogeneity of the red tourism network along the Jiangsu section of the Grand Canal is relatively poor, and the development speed of red tourism is fast in the southeast and slow in the northwest. (3) The development of red tourism in Jiangsu section of the Grand Canal is influenced by the regional policy support, the level of economic development and the construction of smart tourism. The integration of cross-city cultural and tourism exchanges plays a role in promoting its development. The epidemic situation has a certain impact on red tourism, but the change of tourists’ tourism preference brings a turning point for more less well-known scenic spots.

Based on the definition of “Red Village”,this paper takes 262 rural red tourist attractions as data samples in Hunan province,using mathematical modeling and GIS spatial analysis methods to quantitatively describe the spatial distribution pattern and accessibility characteristics of red villages.The results show that:（1) The red villages in Hunan are in the state of agglomeration distribution,the unbalance of red villages distribution in different regional spaces or administrative units is prominent,and the agglomeration intensity constantly decreases with the increase of scale distance; (2)The red villages show a distribution pattern of “large dispersion and small agglomeration”,and there are three high-density agglomeration areas as well as a number of transboundary continuous clusters of red villages.Along the long march route and in the border area of Hunan- Hubei-Jiangxi and Hunan-Guangdong-Jiangxi,many “medium and low density” agglomeration areas are formed;（3)The average transit time of red villages is 221.58 min, the standard deviation is 42.75,the overall accessibility is not ideal and internal difference is significant, the robustness of the accessibility level is poor,the mathematical distribution of red villages in different accessible periods approximately presents the “pyramid” structure;(4) The spatial distribution of accessibility of red villages shows the “center-periphery” structure,several traffic accessibility valleys are formed in the provincial marginal areas and having “spatial dislocation” with its kernel density pattern,and showing obvious traffic directivity characteristics.Finally,the paper puts forward some suggestions to optimize the accessibility pattern of red villages,drive the reconstruction of traffic location and promote the development of red tourism.

River hydrological regime is regarded to be the key driver of river ecosystem. In order to study the alternation of the hydrological regime of the Jialing River basin caused by the construction of water conservancy projects, the change characteristics of flow regime were evaluated by using the Mann-Kendall statistical test, the cumulative departure and moving T detected method based on daily flow series at the representative hydrological station of the Jialing River-Beibei Station from 1956 to 2017, while the hydrologic regime alteration degree and fish ecological effect of Jialing River on the variation of 32 hydrological indexes were also analyzed by the range of variability approach and hydrologic regime alteration degree method. The results show that annual average flow of the Jialing River has shown a decreasing trend during 1956 to 2017. The abrupt junction of annual average flow is 1993 year. Through the analysis of the eco-hydrological indicators before and after the change of hydrological regime, it is concluded that the alternation degree of Beibei gauge station was 50%. The overall degree of hydrological alternation belongs to moderate alternation, and the change degree of the hydrological index of the number of reversals reaches 100%. Compared with the changes in fish composition, the number of some drifting fishes and large economic fishes adapted to the torrent habitat decreased significantly, and it was concluded that the operation of the trapezoidal reservoir in Jialing River had a great impact on fish diversity. This study can provide reference for ecological restoration and sustainable development of Jialing River Basin.

In order to understand the current status and temporal distribution of early-life-history-stage fish resources associated with environmental factors and hydrological processes in the Luzhou reach of the upper Yangtze River, The middle of the "National Nature Reserve of Rare and Enemical Fish in the Upper Reaches of the Yangtze River", Luzhou section of the upper reaches of the Yangtze River, is a key area for the protection of fish resources and an important habitat and migration channel for fish. In order to accurately assess the status of early fish resources in the lower reaches of the dam after the impoundment of the Jinsha River cascade projects, understand the status of early fish resources in the Luzhou section of the upper reaches of the Yangtze River, and explore the impact of environmental factors and hydrological processes on early fish resources, fish resource surveys primarily on collecting drifting fish eggs and fry were carried out in the Luzhou section from May to July in 2019 and 2020. The temporal changes for the density of the egg and larvae as well as the relationships with hydrological indicators were then subsequently analyzed. During the investigation, a total of 2 153 fish eggs and 1703 larvae were collected. There were 18 fish species belonging to 2 orders, 3 families and 15 genera were identified through molecular biology methods. The dominant fish populations for the two years both were Rhinogobio typus, Pseudolaubuca engraulis and Coreius heterokont, the spawning amount of which accounted for 52.25%, 13.51%, 9.91% of the total in 2019 and 25.44%, 17.98%, 29.39% in 2020, respectively. The average fish larvae density was 0.31 ind./100 m³ and 0.78 ind./100 m³ in 2019 and 2020, and the peaks appeared in late June to early July. The results showed that fish larvae density is significantly positive with water discharges from the dam of Xiangjiaba and water level in this reach（P<0.05）, however, significantly negative with water transparency（P<0.01）.The increase in flow caused by upstream water during the breeding season is a key ecological hydrology index that affects fish spawning.

The industrial land market is the key carrier to promoting the market-oriented allocation reform of the elements in the Yangtze River Economic Belt, and the accurately quantity of the market-oriented level of the chemical industry land is the objective need to promote the rational flow of the elements in the region and to build a high-quality development of the land and space layout. Using GIS spatial analysis and Dagum Gini coefficient method to systematically investigate the evolution characteristics of the spatial and temporal pattern of industrial land marketization level in the Yangtze River Economic Belt from 2007 to 2018, and using the spatial Dubin model (SDM) to reveal the main influencing factors of industrial land marketization level. The results show that: (1) The marketization level of industrial land in the Yangtze River Economic Belt has been improved as a whole during the research period, but there are some regional differences, which are manifested in the downstream>upstream>middle reaches. (2) Hyper-variable density is the main source of the market-oriented level gap of industrial land in the Yangtze River Economic Belt. (3) There is a positive spatial interaction effect in the marketization level of industrial land in the Yangtze River Economic Belt, in which financial constraints, competition among local governments, level of economic development, industrial structure and investment in fixed assets are the main factors affecting the marketization level of industrial land.

Space conflict is the basis of national spatial optimization and even national spatial planning.On this basis, the article constructs the national spatial optimization idea based on space conflict, and by natural resources endowment condition is superior, the more appropriate sex strong, regional resources and environment of high load bearing in jiangsu province as an example, the analysis of the sustained and rapid economic and social development caused by the shortage of arable land resources, regional environment and continuous increase of load space conflict,And ecological, agricultural and urban spatial structural contradictions, put forward the territorial space optimization model based on the restricted regional factors, thus the proportion of the most important regions for ecological protection, the suitable regions for agricultural production and the suitable regions for urban construction are respectively:8.81%, 54.24% and 46.92% of the land space with main function conflict, and the main function pattern of ecological space, agricultural space and urban space accounted for 14.46%, 59.51% and 26.03% respectively, reflecting the harmonious coexistence and development characteristics of human and nature in Jiangsu province, which is a strong economic province and a big agricultural province.It provides a scientific basis for mitigating the spatial conflict between ecology, town and agriculture and for carrying out territorial space governance scientifically.

The urban waterfront recreation space and recreation activities interact each other, recreation space provides material base for recreation activities, affect the time and space distribution of the recreation activities, recreation activities guide the layout, function and characteristics of the recreation space elements, Only the coordinated development of the two can promote the sustainable and high-quality development of the recreation space in the urban waterfront. Taking the waterfront of Qinhuai river in Nanjing for example, based on the electronic map point of interest (POI), Baidu thermal chart, construction of urban waterfront recreation space and recreation activities coupling model, coupling elements on its recreation space and recreation activities coordination characteristics and the influence mechanism is analyzed, the results show that: (1) the overall coupling coordination degree of waterfront recreation space and recreation activity of Qinhuai river in Nanjing is low; The coupling coordination degree is generally not balanced, “high in the middle, low on both sides”, with Confucius Temple as the center, the more to the periphery the coupling coordination degree is lower. (2) The coupling coordination of production space is the best, followed by living space and public space, and the landscape space and ecological space is the lowest. The coupling forms of recreation space elements and recreation activities are different among different types in working days and rest days.(3)The coupling of recreation space and recreation activities in the Qinhuai River waterfront in Nanjing is influenced by the market supply and demand mechanism, agglomeration-diffusion effect and government regulation mechanism.

Population agglomeration and industrial agglomeration are included in the analytical framework of pollution influencing factors, and the spatial Durbin model is used to explore the effects of population and industrial agglomeration on production and consumption pollution and spatial spillover differences by using provincial panel data from 2000-2018 in China. It is found that industrial agglomeration exacerbates production and consumption pollution within and adjacent to regions, and moderate population agglomeration is conducive to optimizing resource allocation and promoting the sharing of pollution control facilities, which can mitigate production and consumption pollution within and adjacent to regions. Production pollution is in line with the environmental Kutznets curve, while consumption pollution is mainly influenced by the consumption level, and everyone is the main subject of pollution. Consumption pollution is much more difficult to manage than production pollution, and should be managed from the level of consumption demand.

In order to promote the green transformation of the transportation industry in the Yangtze River Economic Belt and achieve coordinated development of the transportation industry and carbon emission reduction, the study analyzes the decoupling situation and driving factors between the economic development of the transportation industry and the carbon emissions of transportation energy during 2004 to 2018, with a combined use of the Tapio decoupling model and the LMDI factor decomposition approach. The results show that both the total and per capita carbon emissions of the transportation industry were on the rise in the Yangtze Economic Belt from 2004 to 2018, and the carbon emissions from petroleum energy consumption accounted for 95.51% of the total emissions. The decoupling of transportation carbon emission in the belt was mainly "weak decoupling", with "connecting growth" and "expanding negative decoupling" in some years, and the decoupling state was unstable. On a whole, the economic development of the transportation industry in the belt has not yet shaken off its dependence on transportation energy carbon emissions. To be specific, scale of transportation industry, economic growth and population size restrained, while transportation energy intensity and energy structure promoted the decoupling of transportation energy carbon emissions in the belt. Among the factors, economic effect is the main factor impeding the decoupling of transportation energy carbon emissions, while energy intensity effect is the main factor promoting it. Based on the findings, the study puts forward relevant suggestions on facilitating economic restructuring, optimizing transportation energy consumption structure, boosting scientific and technological innovation, and strengthening transportation demand management (TDM) as effective measures to realize the coordinated development of transportation industry and carbon emission reduction in the belt.

The present study used spatial autocorrelation analysis, geo-detector and mixed geographically weighted regression (MGWR) methods to analyze the 2017-2019 PM_2.5 data of three urban agglomerations along the Yangtze River Economic Belt under the National Monitoring System and established multiple spatial scales, multiple impact indicators and multiple analysis models for a comprehensive assessment of the PM_2.5 concentrations. The results showed that: (1) The PM_2.5 concentration in the three urban agglomerations had a generally downward trend over the three years. The average PM_2.5 concentration in the Yangtze River Delta urban agglomeration was the lowest for the three years under the study, and the average PM_2.5 concentration in the Yangtze River Middle-Reach urban agglomeration was the highest for the three years, but the decline was the largest. The air quality in the Cheng-Yu urban agglomeration was overall between the levels of the two aforementioned agglomerations. (2) On the seasonal scale, PM_2.5 concentration was higher in the spring and winter, but lower in summer and autumn. (3) From the spatial perspective, air pollution in the north of the Yangtze River was more severe than that in the south of the Yangtze River. The air quality in the eastern and southern parts of the Yangtze River Delta urban agglomeration was better than that in other regions of the same agglomeration. The air quality in the northwest part was worse than other regions of the Yangtze River Middle-Reach urban agglomeration, and for the Cheng-Yu urban agglomeration, the air quality in the eastern part was better. (4) Meteorological elements and socio-economic status were the main factors affecting the PM_2.5 concentration. Among social and economic factors, the urbanization rate was found to be most impactful for PM_2.5 pollution from 2017 to 2019, followed by industrial enterprises above designated size. Among meteorological factors, total precipitation, maximum temperature and other factors showed a strong weakening effect on PM_2.5 pollution. In general, the current urbanization process had a greater impact on PM_2.5 pollution.

The study chose Jiangxi Province as the study area, to explore the spatio-temporal characteristics of urbanization development and atmospheric particulate matter pollution and their coupling coordination relationship. It is expected to provide effective reference on coordination between urbanization and the atmospheric environment for Jiangxi Province and other less developed areas. Spatial autocorrelation method was used to analyze the spatio-temporal distribution characteristics of urbanization level and atmospheric particulate matter, and coupling coordination degree model was constructed to analyze spatio-temporal variation of relationship between urbanization level and atmospheric particulate matter. The results show that：(1) From 2015 to 2019, the comprehensive urbanization level increased steadily, and concentrations of PM_2.5 and PM₁₀ increased first and then decreased. (2) The comprehensive urbanization level present spatial discrete characteristic, PM_2.5 and PM₁₀ concentrations present obvious spatial agglomeration characteristic since 2016. The local autocorrelation characteristics of comprehensive urbanization level, PM_2.5 and PM₁₀ are highly consistent, showing spatial overall distribution characteristic of "high in the northwest and low in the southeast". (3) From 2015 to 2019, the coupling coordination degree between comprehensive urbanization level and atmospheric environment increased，showing the urbanization development is atmosphere-friendly. Increase of coupling coordination degree between 11 cities are significantly different, and there is still large improvement for some cities. The coupling coordination degree is spatially discrete, with a distribution pattern of "high in the middle and low around". Nanchang, the capital of Jiangxi, has already achieved a good coordination between urbanization and atmospheric environment. However, most of the other cities are still developing at the cost of decreasing ecological environment. It is suggested to explore new urbanization paths for different cities according to the regional characteristics.

Under the background of global climate change, the drought problem induced by uneven rainfall has seriously threatened crop growth and food security. Exploring the drought characteristics of Jiangxi Province provides theoretical references for disaster prevention, drought resistance,and crop growth. Daily precipitation data of 15 standard meteorological stations in Jiangxi Province from 1957 to 2015 were collected.Then,continuous days without available precipitation(Dnp) was adopted as a drought index to calculate drought frequency,drought station ratio,and drought duration days of different seasons.Finally,the spatial distribution characteristics of drought frequency and  inter-annual variation trend of drought station ratio and drought duration days were obtained.In addition, daily drought frequency was introduced to study dynamics change of different stations in Jiangxi Province. The results showed that: (1) summer and autumn droughts occurred frequently in various regions of Jiangxi Province, which commonly occurred from July to November;(2) spring drought mainly occurred in southern Jiangxi, and the areas with high summer droughts were mainly in the Poyang Lake Plain and southern Ganzhou. Only a small part of the province had mild autumn droughts, and most other areas had severe autumn droughts.The winter drought exhibited a gradually increasing trend from north to south.The worst-hit area of drought in Jiangxi Province was Ganzhou,which suffered from severer droughts throughout the year;(3)The whole province and the sub-regions had the same inter-annual change trend. The inter-annual change trend of spring drought and autumn drought showed an increasing trend, and only the drought intensity in southern Jiangxi decreased slightly. The inter-annual change trend of summer showed a decreasing trend. The winter drought showed an increasing trend in covering area,but a sightly reduction in intensity. The drought situation in southern Jiangxi showed an overall weakening trend, and only the winter drought intensity showed an increasing trend.

Soil organic carbon plays an important role in wetland ecosystem and global carbon cycle, which is also an essential link between the internal and external material circulation of wetland system.  Poyang Lake is the largest fresh water lake of China which connects with Yangtze River in the middle and lower reaches. The migration and transformation of soil organic carbon in this lake is of great significance to the regional and even global carbon dynamics. Based on systematic investigation and sample analysis, the spatial distribution pattern of soil organic carbon and its relationship with soil characteristics, vegetation and elevation in Poyang Lake were analyzed. The results showed that: (1) The average content of soil organic carbon in Poyang Lake wetland was 4.38%, with the higher content distributed in the north central part of the main lake area and in the southern lake bay area, and the lowest content was found in the northern channel into the river. The content of organic carbon in delta wetland and dish-shaped lakes was significantly higher than that in river channels; (2) Based on the geographically weighted regression (GWR) model, total nitrogen, total phosphorus, water content, elevation and vegetation normalization index (NDVI) explained 35.28% variation of soil organic carbon (overall R²=0.35) in Poyang Lake wetland. The local R² values was high in the southeast and low in the northwest，and its value in dish-shaped lakes and delta wetland was significantly higher than those of river channels (P < 0.01); (3) The effects of different impact factors on organic carbon varied across regions. The relationship between total nitrogen and organic carbon was stronger in the western lake, and stronger in river channel and delta wetland, while the link between total phosphorus and organic carbon was stronger in the southeast and northwest of the lake area, and had a strong influence in delta wetland and dish-shaped lake; The influence of water content on organic carbon was relatively stable on a lake-wide scale; The effect of NDVI was stronger in the south and east, and stronger in shoal and dish-shaped lakes; The influence of altitude had a higher coefficient value in the southeastern part of the lake, and in delta wetland and dish-shaped lake.

Converting farmers′ cultivated land protection willingness into behavior, and unifying their willingness and behavior, is one of the effective measures to solve the problem of cultivated land protection. In this paper, the theory of social embeddedness is applied to farmers' cultivated land protection. Firstly use Logit model to measure the degree of social embedded factors influencing farmers′ cultivated land protection willingness and behavior paradox, and then use interpretive structural model to further analyze the relationship and hierarchy between the various factors. The results show that: (1) Farmers′ education level, employment status, percentage of agricultural income, arable land area, policy propaganda, economic output value cognition, social security value cognition, interpersonal trust, institutional trust, strong connection network have a significant impact on the occurrence mechanism of paradox between farmers′ cultivated land protection willingness and behavior. (2) The education level, employment status, cultivated land area and policy propaganda are deep-rooted factors. These root factors affect the percentage of agricultural income, interpersonal trust, institutional trust and strong connection network. Economic output value cognition, social security value cognition are the direct surface factors that directly drive the occurrence of paradox between farmers′ cultivated land protection willingness and behavior.

The characteristics of the river basin landscape have a significant impact on the migration and output of nitrogen (N) and phosphorus (P) in river basins, but its relationship with the output load of river N and P and its contribution need to be further studied. This study takes the Jinjing River Basin as the research area, and quantitatively estimates the river N and P output load based on long~term hydrology and water quality positioning observation data. Based on the classification of landscape index combined with the core landscape index of different landscape scales selected by traditional statistical analysis, redundancy analysis (RDA) and variance analysis (VPA) are used to clarify that the characteristics of landscape pattern at different scales in the typical subtropical agro~forestry mixed watershed are important for river N, P The influence of output load. The results show that the output load of N and P in the river basin during the flood period and the dry and dry period is significantly different in time and space. The output load of TN, NH₄⁺-N, NO₃^--N, TP, and DIP in the river basin during the flood period are 2.61-9.03, 0.34-5.34, and 0.34-5.34, respectively. 1.26-5.03, 0.15-0.50, 0.09-0.23 kg/(hm2.a); the flat and dry seasons were 1.55-6.68, 0.29-2.91, 0.74-2.91, 0.10-0.46, and 0.05-0.20 kg/(hm2.a), respectively. Different landscape scale levels and land use types, landscape characteristics have different effects on N and P output loads, but at the same scale level, the impact of various types of landscape indexes on the N and P output loads of rivers during high and low water periods is basically the same . At the landscape scale, the increase in the concentration of different types of patches and the increase in landscape diversity will lead to an increase in the output load of river N and P; the output load of river N and P is related to the large area, high concentration, and high connectivity of farmland and residential land. Blocks are significantly positively correlated, and significantly negatively correlated with high~aggregation and large~area woodland patches. The main impact index categories of farmland patches on river N and P loads in wet and dry periods are area~margin and aggregation index respectively. The impacts of forest land and residential land patches at different water level periods remained unchanged, and they were respectively the area~margin and agglomeration category indexes. The results of this study can provide theoretical support and scientific basis for the management of agricultural non~point source pollution in the river basin from the perspective of landscape planning.