The Party’s twenty Congress pointed out that the problem of unbalanced and inadequate development was still severe and put forward stricter requirements for regional coordinated development in the future. Promoting the coordinated and balanced regional development of the economic belt along the Yangtze River is an important way to “improve the balance, coordination and inclusiveness of development” and an important approach to achieve common prosperity and high-quality development. Based on the adjusted coordinated and balanced development index evaluation index system, this study used statistical data in 2019 and 2020, and employed a variety of quantitative analysis methods to reveal and compare the current situation of coordinated and balanced development of the Yangtze River Economic Belt. The main conclusions were as follows: (1) Compared with 2019, there was an increase in 2020 in the absolute value of the coordination equilibrium index of 110 cities at the prefecture level and above in the Yangtze River Economic Belt. It was also observed that the range decreased compared with 2019, and there were still large differences among different regions; (2) From the second and third level indicators, public basic services and public infrastructure in the equilibrium degree, industrial coordination, and market unity and economic coordination in the integration degree were the main reasons for the differences among 110 cities. (3) The 110 cities in the Yangtze River Economic Belt were divided into 5 types based on the K-cluster clustering method. Differentiated regulation strategies and optimization paths were proposed for these 5 types of cities.

Rural tourism is an important way to promote rural revitalization and achieve common prosperity, and plays an important role in the overall development of urban and rural areas and the coordinated development of regions. Taking the urban agglomeration in the middle reaches of the Yangtze River as the research area, this study systematically analyzed the spatial differentiation of the key rural tourism villages in the urban agglomeration in the middle reaches of the Yangtze River, with the help of ArcGIS 10.6 spatial analysis tool and the methods of nearest proximity index, disequilibrium index and geographic detector. The results showed that: (1) On the whole, the local agglomeration characteristics of rural tourism key villages in the study area were obvious, with 2 high density areas and 4 sub-high density areas, showing the characteristics of being near economically developed, natural and cultural rich areas. They were mainly distributed in the eastern and southern parts, such as Shangrao, Fuzhou, Ji ’an Hengyang, Changsha and other cities. (2) From the perspective of type structure, the rural tourism types of the study area mainly included agricultural production, cultural and folk customs, scenic attraction support, natural ecology and red ruins, and most of them were distributed in a cohesive pattern. The rural tourism key villages with agricultural landscape sightseeing and agricultural product picking as the main products accounted for a large number. The development mode of rural tourism was single; (3) From the perspective of influencing factors, the spatial distribution of the key villages of rural tourism was affected by both natural and human factors, among which the traffic conditions had the most significant influence, followed by permanent population and economic development level. In addition, the spatial distribution of the key villages of rural tourism was the result of the comprehensive effects of natural and social economic factors. The effect of the interaction of two factors was more significant than that of the single factor, showing two kinds of effects: nonlinear enhancement and double enhancement. Finally, according to the type structure and spatial distribution of typical rural tourism resources , this study provided suggestions on the linkage development of rural tourism, in order to strengthen the role of rural tourism in urban and rural coordination and regional development.

It is of great significance to clarify the coordination mechanism between county urbanization and rural sustainability for implementing the idea of urbanization construction with the county as the carrier. Based on the remote sensing data of land use and related statistical data, the spatial-temporal evolution characteristics and corresponding driving mechanism of coupling coordination between county urbanization and rural sustainability in Jiangsu from 2000 to 2020 were analyzed, by using the coupling coordination degree model, relative development degree model and geographical detector. The results showed that: (1) The county urbanization, rural sustainability and their coupling coordination were gradually optimized. The coupling coordination degree had completed the leap of ‘antagonistic stage→running-in stage→coordination stage’, presenting the spatial pattern of ‘high in the south and low in the north’. （2) The types of coupling coordination mainly included rural sustainability lagging type and synchronous development type, and generally were experiencing the evolution process from low-level type to high-level type. (3) The spatial-temporal evolution of coupling coordination was mainly driven by the factors such as economic development, government behavior and openness. And the interaction of internal and external factors realized the multiplier effect of coupling coordination degree. Based on the research results, policy suggestions were put forward from the aspects of differential path construction, cross-regional linkage and multi-agent coordination to promote the integration and symbiosis of urban-rural areas.

The contradiction between China’s economic development and the protection of natural resources and the environment remains prominent. Reducing the damage and impact of economic activities on the natural resources and the environment through the scientific optimization of the organization structure and spatial layout of human activities is an important research topic in geography.Based on network externalities, this study focused on inter-regional economic correlations and their impact on the resources and environmental pressures, and explored the internal formation mechanism to break through physical boundaries. This study aimed to better understand the impact of spatial organization modes on resource use and environmental pressure. This paper examined the connection between county-level economic spatial networks and eco-efficiency exemplified in Jiangsu Province. The findings were as follows: (1) County-level eco-efficiency demonstrated fluctuations with an upward trend and showed zone differences, with higher eco-efficiency levels in municipal districts than other counties. (2)Spatial correlations among the county’s economy became increasingly tight, while connectivity, accessibility, and stability were continuously improved. However, the spatial correlation and interaction level remained weak. The spatial distribution characteristics indicated that point degree centrality, proximity centrality, and intermediate centrality were higher in the south and lower in the north, with an increase in mean value and range over time. (3) It was found that increases in network density and correlation degree, and decreases in average path length and network efficiency could improve overall ecological efficiency. Point centrality degree might promote local county and overall ecological efficiency. Proximity to the center could enhance local ecological efficiency but might hinder improvements in other counties and overall ecological efficiency. Meanwhile, intermediate centrality could raise the ecological efficiency of the local county, other counties, and the entire region. The impact of the county economic spatial network on eco-efficiency mainly came from the spillover effects in the network externality of the county economic spatial network. This study demonstrated the close relationship between county-level economic spatial networks and eco-efficiency. The economic spatial networks affected ecological efficiency through the attributes of nodes and edges. The centrality and externality of economic spatial networks jointly influenced eco- efficiency. Based on the findings of this study, relevant policy recommendations were proposed.

Circular economy emphasizes on sustainable development and green finance adherent to environmental protection. Based on the panel data of 12 cities in Hubei Province from 2009 to 2020, an evaluation index system of circular economy and green finance was established by using the entropy method. The coupling coordination model and exploratory spatial data analysis method were used to analyze the coupling coordination level and spatio-temporal distribution characteristics of circular economy and green finance in Hubei Province. The research indicated that: (1) The development of circular economy in Hubei Province showed an upward trend from 2009 to 2020. Meanwhile, green finance showed an increase in volatility. The development level of green finance lagged behind the development level of circular economy. (2) The coupling level of circular economy and green finance in Hubei Province was high. In the time dimension, the coupling level of circular economy and green finance in 12 cities was developing continuously. In the spatial dimension, the development of coupling level in 12 cities was evenly distributed. (3) The coupling coordination level of circular economy and green finance in Hubei province was gradually increasing, with the overall distribution characteristic of high in the east and west, and low in central Hubei in space; Wuhan was in the lead among the 12 cities in Hubei Province. (4) From 2009 to 2020, there was a significant spatial negative auto-correlation between the coupling and coordination level of circular economy and green finance system in Hubei Province. It showed “high-low” aggregation from the center, Wuhan, which indicated that there was an obvious spatially discrete characteristics between the two systems of prefecture-level cities in Hubei Province. At last, to further improve the coupling and coordination level of circular economy and green finance system, and promote the coordination between economic development and environmental protection in Hubei Province, corresponding policy suggestions were put forward.

To systematically understand phytoplankton community structures and the corresponding impact factors, an investigation was carried out at 71 sites in the mainstream, eight primary tributaries, the Dongting Lake, and the Poyang Lake in the Yangtze River basin. The characteristics of the phytoplankton community structures were compared among different water areas and periods. The impact factors contributing to the differences of phytoplankton community structures were further explored. Results revealed that the abundance and biomass of phytoplankton in the Yangtze River basin ranged from 0.07×104 to 2 493.69×104 cells/L, and from 0.001 1 to 21.072 2 mg/L, respectively. Bacillariophyta, Chlorophyta, and Cyanophyta were the dominant phytoplankton phyla. From west to east of the Yangtze River basin, the total abundance and biomass of phytoplankton and proportion of Cyanophyta and Chlorophyta showed an increasing trend, while the proportion of Bacillariophyta abundance decreased gradually. The average total abundance and biomass of phytoplankton in the fish fattening period were higher than those in the fish breeding period and the overwintering period, characterized by higher proportion of Cyanophyta and Chlorophyta and lower proportion of Bacillariophyta. Moreover, the results of redundancy analysis, hierarchical partitioning, and variation partitioning indicated that both environmental and spatial variables contributed to the variance of phytoplankton community structures in the Yangtze River basin. In the fish fattening period, the environmental filtering effects were dominant, of which the water temperature was the most important factor and was strongly positively correlated with the total and dominant phyla abundance of phytoplankton. In the fish overwintering period, the differences in the phytoplankton community structure were better explained by spatial factors rather than the environmental factors, of which the spatial factor of MEM3 was the main factor. This study provided important data for the management of the aquatic ecology in the Yangtze River basin.

Starting with the stage identification and transformation process division of regional economic-social development, this paper explored the driving forces of land use change in the middle reaches of the Yangtze River (MRYR), by using the least square model, spatial lag model, and spatial error model. The results indicated that: (1） The economic-social development stage of the MRYR have undergone two transition processes during 2000-2018. The first was from the primary production stage II to the middle industrialization stage, with slow growth of urbanization and serious outflow of population, the corresponding period was 2000-2010. The second was from the middle industrialization stage to the late industrialization stage, with steady growth of urbanization and continuous return of population, the corresponding period was 2010-2018. （2) In terms of overall characteristics of land use change, the cultivated land and ecological land continued to decrease, the construction land area continued to increase, and the unused land area remained relatively stable during 2000-2018. In terms of process characteristics of land use change in 2000-2010, cultivated land and forest land were transformed into each other. The major changes were that cultivated land was transformed into construction land and water area, and water area was transformed to wetland. In 2010-2018, cultivated land and construction land were transformed to each other, forest land was transformed to construction land and cultivated land, and wetland was transformed to water area. (3） In 2000-2010, topographic index was the sole common driving factor of five main types of land use change. In 2010-2018, topographic index, per capita GDP change, total population change, and distance from main roads became the common driving factors. Therefore, the government should fully consider the main drivers of various types of land use change, as well as their laws of economic-social development and geographical differentiation, so that land use change could be better adapted to regional natural environmental conditions and economic-social development stage.

Investigation on the characteristics and regulations of changes of land use and ecosystem service value (ESV) in the Wuhan urban agglomeration under multiple scenarios is of significant for regional land use planning and ecosystem conservation. Based on the land use data in 1990, 2000, 2010 and 2020, we revealed the temporal-spatial evolution trends of land use and ESV in Wuhan urban agglomeration; We simulated the land use in Wuhan urban agglomeration under four scenarios of tendency inheritance,cultivated land preservation, ecological conservation, and balanced cultivated land and ecological using CA-Markov model, and analyzed the structural change trends and spatial flow characteristics of ESV. The results showed that: （1) From 1990 to 2020, land use changes in the Wuhan urban agglomeration presented significant phase characteristics, which generally showed a substantial transfer of cultivated land to construction land and water, resulting in a sharp loss of 1 868 km2 of cultivated land,while forest land and water area had a relatively significant shift to construction land, leading to a continuous expansion of 1 569.93 km2 of construction land. The ESV showed a decreasing trend of 1.66%. Fluctuations of ESV in the urban area of Wuhan, Xiantao and Qianjiang were obvious. (2) Tendency inheritance and cultivated land conservation scenarios had elevated ESV losses of 117 million yuan and 81 million yuan respectively, which were primarily influenced by the decreased forest land and water areas; the ecological preservation scenario followed, and the reduction of cultivated land played a prominent role in the reduction of ESV; the cultivated land and ecological balance scenario caused the expansion of water areas and forest land, contributing to the radiating increase of ESV centered in Wuhan City. （3) The magnitude of variation in ESV spatial mobility was relatively moderate, displaying an overall inflow from the surrounding higher ESV cities in the eastern and southern regions to the regional center. The dominating ESV outflow cities were QiChun County, Luotian County and Chibi.

Clarifying the vertical differentiation characteristics of soil carbon (C), nitrogen (N), phosphorus (P) , and their ecological stoichiometry along the water level elevation under the periodic flooding-emergence conditions is beneficial to the soil nutrient management in the water level fluctuation zone(WLFZ). In this study, the typical riparian zone  of the Three Gorges Reservoir was taken as the research area. Soil samples were collected at depths of 0-10, 10-20, and 20-30 cm at water level elevations of 145-155, 155-165, and 165-175 m, with the unflooded grassland at elevation of 180 m as the upper limit. Soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), pH, soil bulk density (SBD), soil water content (SWC), soil mechanical composition, and agglomerates were analyzed. The purposes of this study was to explore the ecological stoichiometric characteristics of soil C, N, and P at different water level elevations and soil layers and to identify the influencing factors. The results showed that: (1) Change of water level elevation affected the soil C, N, and P contents. The mean values of SOC, TN, and TP in the WLFZ were 8.70, 0.79, and 0.63 g/kg, respectively, which were lower than those in the unsubmerged area. With the increase of water elevation, the soil SOC and TN contents increased, and TP content decreased, and the nutrient contents of the surface soil were higher than those of other soil layers. (2) The mean values of soil C/N, C/P, and N/P were 11.67, 15.37, and 1.47, respectively, where C/N and C/P were higher than those of the unsubmerged area and N/P was lower than that of the unsubmerged area. As the water level elevation increased, soil C/N decreased and C/P and N/P increased. There existed a good coupling relationship between soil C, N and P. Nitrogen might be the limiting soil element in the WLFZ, and there was a risk of nitrate leaching. （3) Correlation analysis showed that soil physicochemical properties significantly affected the contents of soil C, N and P (P<0.05), thus regulating the ecological stoichiometric characteristics. Of all the influencing factors, soil pH, bulk density (SBD), and water-stable agglomerate composition were the main ones, followed by soil water content (SWC) and particle size distribution. These findings implied that the periodic flooding-emergence process leaded to the reduction of soil C, N, and P contents and further affected their stoichiometric ratios in the WLFZ. Therefore, in the future, the configuration of soil conservation measures and nutrient adaptations should be adopted according to the spatial distribution patterns of soil C, N, and P ecological stoichiometric characteristics at different water level elevations. This study was expected to provide a scientific basis for soil erosion control and vegetation restoration in the WLFZ of the Three Gorges Reservoir.

It is of great significance to study the spatial and temporal variation characteristics of evapotranspiration (ET) and explore its driving factors for the scientific allocation and rational utilization of water resources in southwest China. Using MODIS16 ET data, contemporaneous meteorological data and DEM data, based on trend analysis, coefficient of variation method and geographic detector method, the spatial and temporal variation and volatility of ET and the driving factors were analysed in southwest China during 2000-2020. Results showed that: (1) The interannual ET showed an increasing trend with fluctuation in southwest China and each geomorphic regions, especially in Guangxi hilly region. (2) The annual average ET was relatively higher in southwest and southeast, and relatively lower in other regions in southwest China. The interannual ET was dominated by relatively low fluctuation regions. The fluctuation was obviously in Sichuan Basin. The ratio of area where ET showing a significant increasing trend were all greater than 50% in different geomorphic regions, and the ratio in Ruoergai Plateau was the largest. (3) Factor detection results showed that precipitation was the dominant factor that influenced the spatial heterogeneity of ET in southwest China, with an explanatory power of 57.3%. Climate was the dominant factor resulting in the spatial heterogeneity of ET in Yunnan-Guizhou Plateau, Ruoergai Plateau and Hengduan Mountain, while the dominant factor was vegetation in other geomorphic regions. The dual-factor interactive detection results showed nonlinear enhancement or dual-factor enhancement in the study area. The interaction between precipitation and NDVI explained 64.9% of ET’s spatial difference in southwest China. The interaction between climatic factors and elevation in the Ruoergai Plateau, and the interaction between climatic factors and elevation or NDVI in other geomorphic regions were the dominant factors that caused the spatial differentiation of ET. The study revealed the spatio-temporal variation characteristics of evapotranspiration and the corresponding influencing factor, which could provide scientific decisions for the rational use of water resources in southwest China.

Net primary productivity (NPP) of vegetation is an important indicator of the carbon balance in terrestrial ecosystems. Studying the impact of climate change and human activities on NPP is of great significance for achieving carbon neutrality goals and improving ecosystem functions. Based on MOD17A3HGF data, meteorological data, DEM data, and land cover type data, this paper analyzed the spatiotemporal distribution pattern and trend characteristics of vegetation NPP in Chongqing from 2001 to 2020, using trend analysis and partial derivative analysis methods. The contribution of climate factors and human activities to NPP changes was quantified, and the driving factors of NPP changes were explored. The results showed that: (1) From 2001 to 2020, the average value of NPP in Chongqing was 620.29 gC m-2, and the spatial distribution of vegetation NPP showed a gradually increasing pattern from southwest to northeast along the Yangtze River. (2) In the past 20 years, the overall NPP in Chongqing changed at a rate of 5.38 gC m-2a-1, with a significant increase trend. The area proportions of increasing and decreasing trends in NPP in karst areas were 90.04% and 9.96%, respectively. (3) The contribution of climate change to NPP changes in Chongqing during the study period was greater than that of human activities, and the negative impact of human activities on NPP changes was more significant. The NPP changes in non-karst areas were mainly influenced by climate, and the negative effects of human activities on NPP changes accounted for a larger proportion. The contribution of climate change and human activities to NPP changes in karst areas was comparable, with the negative impact of climate factors on NPP changes accounting for a larger proportion (33.11%) than human activities (28.51%). The implementation of ecological engineering promoted the improvement of NPP. (4) The driving force analysis showed that the NPP changes in the study area were mainly driven by climate and human activities, but there existed significant spatial differences. The increase of NPP in the west and northeast of Chongqing was mainly driven by climate and human activities. The increase of NPP in central Chongqing was primarily driven by climate change. The increase of NPP in southeast Chongqing and other karst areas was more obviously dominated by human activities, while the negative effect of climate conditions on vegetation NPP in karst areas was more evident.

For the purpose of solving problem of global water environment pollution, China has been carrying out a major institutional innovation-the River Chief System (RCS). Facing the dilemma of environmental protection and economic development, it is urgent to explore whether the RCS can achieve the double dividend of economic growth and environmental governance.Using the RCS as a quasi-natural experiment, we empirically examined the effects of water environment management policies on the development of economic green transformation and their driving mechanisms,by employing the progressive difference-in-differences method, based on a panel data of 108 prefecture-level cities in the Yangtze River Economic Belt from 2006 to 2019. The results showed:(1) The implementation of the RCS had a significant effect on pollution control and could significantly promote the economic green transformation of the Yangtze River Economic Belt. In addition, with the strengthened implementation of the RCS, a stronger effect had been indicated on the promotion of the green economic transformation.(2) The effect of the RCS in the downstream region was more significant in promoting the economic green transformation. Stronger efforts were shown in the low pollution areas, and the green effects of the RCS were especially prominent in the cities with high level of economic development. (3) The RCS could promote the economic green transformation development by stimulating green technology innovation and promoting industrial structure upgrading. The official incentive played an important role in moderating the effects of the RCS in promoting the economic green transformation development.

Polycyclic aromatic hydrocarbons (PAHs) and their oxygenated polycyclic aromatic hydrocarbons (Oxy-PAHs) enriched in soil and sediment can affect human health through the food chain. The reduction of parent PAHs during soil remediation can lead to an increase in the concentration of Oxy-PAHs, which are more toxic, migratory, and bioavailable, resulting in an underestimation of ecological health risk assessment results. The pollution characteristics and influencing factors of PAHs and Oxy-PAHs in tidal flat sediment and paddy field soil from the Yangtze Estuary were analyzed in this study. The ratio method and principal component analysis were used to identify the main sources of pollutants. The results showed that the total concentration of 16 PAHs in sediments ranged from 124.9 ng/g to 259.9 ng/g, with a mean value of 194.8 ng/g, while the total concentration was 43.5-229.8 ng/g, with the mean value of 113.2 ng/g in soils. The total concentration of 11 Oxy-PAHs was 97.7-231.4 ng/g and 87.9-137.2 ng/g in sediments and soils, respectively. The total concentration of PAHs and Oxy-PAHs in sediments and soils were ranked as: natural beaches>long-term paddy fields>reclamation areas>short-term paddy fields. The differences in vertical leaching, microbial degradation, vegetation absorption and transformation, and exogenous input caused by the duration of human development were the most important reasons for the deviations in the spatial distribution of PAHs and Oxy-PAHs concentrations in the Yangtze Estuary sediments and rice field soil. Correlation analysis showed that particle size composition, organic carbon content, and pH were not the main influencing factors for the concentrations of PAHs and Oxy-PAHs in the sediments. The concentration of PAHs in soil was significantly affected by the water content, TOC and the proportion of fine mucous powder particles, and redox potential (Eh). The results showed that PAHs in sediments and soils were mainly from the combustion of fossil fuels and biomass, and the sources of PAHs in soil were more complex and diverse, and the contribution of industrial emissions such as automobile exhaust and coking production could not be ignored.

To investigate the hydrochemical characteristics and controls of surface water and groundwater in Chen Lake Wetland, the water samples of inflowing rivers and main lakes were collected and analyzed in August (rainy season) and December (dry season) 2020. The results showed that the surface water was neutral to weakly alkaline. HCO₃^- and Ca₂⁺ were the most abundant anions and cations, respectively, and the main hydrochemical type was HCO₃-Ca. Surface water components were mainly derived from weathering and dissolution of carbonate rocks and silicate rocks, and were also influenced by cation exchange. The spatial variability of surface water compositions increased from wet season to dry season due to weakening hydrodynamic conditions. The chemical composition of surface water in the wet season was affected by agricultural activities and domestic sewage, and was affected by industrial and mining activities in the dry season, respectively. These observations demonstrated how the hydrochemical composition of the wetland was controlled by a combination of natural factors and human activities.

Except mercury (Hg) pollution, Hg mining areas were often characterized with other heavy metal pollutions. To better understand heavy metal pollution level in goose eggs from the Hg mining area, 10 local goose eggs were purchased from Wuchuan in Guizhou (the Hg mining area) and Anshun in Guizhou (the background area). The concentrations of Cr, Ni, Cu, Zn, Sr, Mo, Ba and Pb in the egg whites and yolks were determined, followed by the evaluation of ecological and environmental risks of goose egg heavy metals, and the sources of heavy metals in goose eggs were finally analyzed. The results showed that:for Wuchuan eggs, the concentrations of Cr, Ni, Cu, Zn, Sr, Mo, Ba and Pb were 0.50, 0.15, 4.20, 36.61, 11.29, 0.22, 19.60 and 0.040 μg/g, respectively in egg whites; The concentrations of Cr, Ni, Cu, Zn, Sr, Mo, Ba and Pb in egg yolks were 0.42, 0.07, 3.04, 53.60, 5.36, 0.37, 72.92 and 0.27 μg/g. In Anshun eggs, Cr, Ni, Cu, Zn, Sr, Mo, Ba and Pb concentrations of egg whites were 0.27, 0.04, 3.93, 0.38, 1.31, 0.11, 0.09 and 0.008 μg/g, and were 0.20, 0.06, 1.65, 39.67, 2.77, 0.28, 3.98 and 0.04 μg/g, respectively in egg yolks. Unlike Anshun area, the concentrations of Ni, Zn, Ba, Sr and Pb in the egg whites and Zn, Ba, Sr and Pb in the yolks from Wuchuan were significantly higher(P<0.05), indicating that goose eggs from the mining area were significantly contaminated with heavy metals. Moreover, the potential health risk of heavy metals from goose eggs was higher for children than for adults, and egg yolks were higher than from egg whites.Factor analysis illustrated that Hg, Zn, Ba, and Pb were mainly from crops; Ni, Cu and Sr were mainly from contaminated water bodies and aquatic plants. Local residents could be at health risks from long-term consumption of contaminated goose eggs. It was highly suggested that local residentsincrease their awareness of heavy metal pollutions and reduce their consumption of local goose eggs.

Ozone pollution prevention and control is one of the three landmark battles of China's "14th Five-Year Plan" period to carry out in-depth pollution prevention and control actions. This study selected the maximum 8h monitoring value of near-surface O3 from 2015 to 2021, explored the temporal and spatial variation characteristics of near-surface O₃ concentration in national, provincial, urban agglomerations and key cities, and discussed the effectiveness of ozone pollution control in China since the "13th Five-Year Plan" period. The results showed that: ①Since the "Thirteenth Five-Year Plan" period, the annual value of O₃ concentration near the surface in China had first increased and then decreased. In 2021, the concentrationdecreased by about 8.2%, compared to the value in 2019, implying that the growing trend was curbed. The high value was mainly concentrated in spring, summer and early autumn from May to September.②The spatial distribution of O₃ concentration near the surface in China showed a pattern of "high in the east and low in the west" bounded by the Hu-Huanyong line. The medium and high-value areas were mainly concentrated in North China and spread to central China and coastal cities. ③The concentration of O₃ near the surface of urban agglomerations showed the characteristics of "contiguous" distribution. The concentration of O₃ in the eastern urban agglomeration was higher than that in the western urban agglomeration. The concentration of O₃ in urban agglomerations in North and East China, such as the Beijing-Tianjin-Hebei urban agglomeration, the Yangtze River Delta urban agglomeration and the Central Plains urban agglomeration, was relatively high.④During the "13th Five-Year Plan" period, the ozone pollution of the upgrading urban agglomerations was significantly improved. The O₃ concentration in the five major urban agglomerations of Beijing-Tianjin-Hebei, Yangtze River Delta, Pearl River Delta, Chengdu-Chongqing and Yangtze River Midstream decreased by 15.51%, 6.35%, 11.66%, 5.26% and 12.56% respectively for 2019 to 2021; The effect of pollution control in central cities was also remarkable; The O₃ concentration in the northern developing urban agglomerations was high, while the O₃ concentration in the other two developing urban agglomerations in the southern coastal area was relatively low. The collaborative emission reduction efforts between cities within developing urban agglomerations needs to be strengthened. The concentration of O₃ in fostering urban agglomerations was relatively acceptable. There were large differences in O₃ concentration in central cities, and the concentration of O₃ in key cities such as Taiyuan, Harbin, Yinchuan and Urumqi showed an upward trend. This study suggested that China's ozone pollution prevention and control battle focus on the spring, summer and early autumn from May to September. Regions of the Beijing-Tianjin-Hebei, Yangtze River Delta and Guanzhong Plain urban agglomerations should be paid more attentions. The prevention and control of ozone pollution in key urban agglomerations (such as the Pearl River Delta, Chengdu-Chongqing and the middle reaches of the Yangtze River)and the cities with severe ozone pollution (such as Tianjin, Shijiazhuang, Nanjing, Hangzhou, Jinan, Zhengzhou and Taiyuan) shouldbestrengthened further.

The implementation of low carbon rice farming aims to increase carbon sinks and to reduce carbon emission.Low-carbon and high-yield is an inevitable choice to achieve the goal of "double carbon" and ensure the "win-win" of national food security. Based on the survey data of 2 173 farmers in Jiangxi Province, this paper introduced the IMB intervention model framework, and used the ordered Probit model and the mediating effects model to empirically test the influencing factors and mediation paths of farmers ' adoption of low carbon rice farming behaviors. The results showed that (1) farmers did not adopt low carbon rice farming behaviors at a high level, and the largest number chose to apply organic fertilizer. (2) In the IMB intervention model, information accessibility, technology understanding, importance motivation, technology training, production communication behavior, and imitation convergence behavior played a significant positive role. (3)Mediating effects analysis showed that technology information could promote farmers' adoption behavior through adoption motivation and behavioral skills, and behavioral skills could also be influenced by adoption motivation to enhance farmers' adoption level. In view of this, in order to promote farmers' adoption of low carbon rice farming behavior, we should strengthen the popularization of low carbon rice farming technology, highlight the demonstration effects of technology adoption, improve the training of low carbon rice farming technology, establishment of an incentive mechanism for low carbon rice farming technology, and carry out relevant low carbon rice farming science and technology research.

Nowadays, the dietary habits of Chinese residents have changed from paying attention to sufficient quantity to emphasis on the balanced collocation of meals, which leads to the changed behavioral strategy and behavior of rural subjects. Based on the concept of big food and on the basis of the cognition of the spatial behavior of rural subjects under the guidance of residents’ dietary needs, the rural value index system was constructed from three dimensions of food supply, food balance and food health, and the spatial characteristics and advantageous value types of rural value in Chongqing were analyzed, and the realization mechanism was also analyzed. The results showed that: (1) The rural value could be divided into food supply value, food balance value and food health value due to the difference of the spatial action behavior of rural subjects under the concept of big food; (2) The rural value of Chongqing presented a spatial pattern of “high in the east, low in the west and prominent in some areas”. The main urban area was dominated by the food supply value, the Wuling Mountain area in southeast Chongqing was dominated by the food health value, and the Three Gorges Reservoir area was dominated by the food balance value. (3) The realization mechanism of rural value was interpreted from the three dimensions of resource endowment, agricultural activity and agricultural policy, based on which the authors put forward suggestions on the realization of rural multi-value under the concept of big food.