Many villages and townships in China have shown the phenomenon of "five Changes" (non-agriculturalization of economy, population aging, empty and desolation, pollution, and impoverishment). There is a problem of disharmony occurred between the development of rural and townships and the carrying capacity of resources and environment. Especially, in the context of the implementation of the Rural Revitalization Strategy, a large number of production elements will be invested in the countryside, so this contradiction would become increasingly prominent. On the other hand, there is a lack of accurate accounting of key resources and environmental constraints and stress factors at the operational level in the management, and there is also a lack of basis for implementing the rural and township development mode and development direction. In this paper, the concept and research progress of resources and environment carrying capacity of rural and township development are defined; the resource and environment division and function type division of rural and township development are carried out; the key constraint factors and threshold calculation principle of water, land and ecology of rural and township development are developed; the comprehensive calculation logic framework of resource and environment carrying capacity of rural and township development are formed, and the key issues and prospects of research on resource and environment carrying capacity of rural and township development are finally pointed out.

As the Project 4 of the National Key Research and Development Program "Development of Resource and Environmental Carrying Capacity Calculation System for Rural and Township Development", the research project was focusing on "Evaluation of Ecological Security and Green Ecological Construction Model of Rural and Township Development", which included identifying the dominant ecological functions of different types of rural and townships in different regions; constructing the calculation system and evaluation model of the carrying capacity of rural and townships, studying the restraining influence of regional ecological security on the development of rural and townships, definituding the suitable industries and optimization approaches for the development of rural and townships under the restraint of ecological security and putting forward the green ecological construction and sustainable model of beautiful livable rural and townships. Since the plan launched in 2018, the research group explored the spatial distribution characteristics, agglomeration degree and dominant ecological functions of ecological townships and featured towns at the national level, and the spatial and temporal patterns of the national comprehensive disaster reduction demonstration community were also analyzed. In addition, based on the dominant eco-function of five important eco-function areas (water conservation, biodiversity maintenance, soil and water conservation, wind and sand fixation, disaster reduction and prevention, etc.), the industrial characteristics of typical townships such as Xinming Township in Huangshan City, Maotai Township in Renhuai City, Wuling Township in Chongqing City, Yueyaquan Township in Dunhuang City, Weizhou Township in Wenchuan County were identified. With the research approach of "point to area" and "point by area", the industrial suitability under the constraints of ecological security in the development of rural and townships were explored, and ecological construction models of different types of beautiful and livable rural and townships were initially proposed as the model of tea industry, wine industry, featured agriculture, eco-tourism, and disaster prevention and mitigation. The research results would provide decision-making support for consolidating the results of poverty alleviation and promoting the environmental management of rural revitalization. And it has great practical significance for the improvement of the carrying capacity and sustainable development of rural and townships in important eco-function areas.

Rural and township development is inseparable from the regional dominant ecological functions and the spatial layout of the Ecological-Production-Living Spaces. To improve the level of ecological safety and effectively reduce poverty, it is necessary to evaluate and calculate the ecological carrying capacity for rural and township development. The related concepts of regions, settlements, village and town are analyzed, and the connotation of the ecological carrying capacity for rural and township development, as well as the attributes of the complex ecosystem are defined. Based on the classification of the types of rural and townships and their development requirements, a method for the evaluation of ecological carrying capacity of rural and township development was further developed, which considers population size, dominant ecological functions and industrial scale. Finally, the paths to improve the ecological carrying capacity for rural and township development was preliminary analyzed, which include reducing the ecological pressure of township construction, improving the ecological elasticity of rural and township development, and enhancing the carrying capacity of the township complex ecosystem. The research results could provide a theoretical and practical guideline for the building of carrying capacity improvement plan and optimization of poverty alleviation policies for rural and township development in important ecological function areas.

The evaluation of resources and environment carrying capacity is the basis of spatial planning and a key part of spatial governance. The existing research on capacity calculation focuses on large spatial units such as provinces, cities and counties, and the evaluation of carrying capacity at small-scale is relatively scarce, which cannot meet the needs of environmental management of villages and townships. In this study, Caiyu Township in Daxing District of Beijing is taken as a case to evaluate the carrying capacity of villages and townships. A comprehensive index system of carrying capacity based on DPSIR model is established to analyze the resources and environment conditions in Caiyu Township. The grading results of carrying capacity evaluation of each village of Caiyu Township and the evaluation of space planning scheme based on the enhancement of carrying capacity are presented, and the results show that there are great differences in resources and environment status among villages in Caiyu Township due to the variety of population density and land use intensity related to the land use structure and economic development mode of the villages. This paper concludes with the future research of carrying capacity evaluation at small-scale, which can provide reference for other regions.

The use of visualized bibliometrics analysis helps the evaluation on the advancement of the researches on rural industry suitability under ecological constraints objectively, which promotes knowledge about frontiers of the researches at home and abroad, thus pushing the research fast forwards in China. With the aid of the CiteSpace software. the bibliometric analysis of the data cited from the Web of Science and China National Knowledge Infrastructure (CNKI) was performed to review the researches on rural industry suitability under ecological constraints both at home and abroad from 1992 to 2020. The relevant international researches for this direction has been pioneering researches on resource carrying capacity and industrial suitability under ecological constraints such as climate change, land use, water resources management, and industrial suitability driven by the economy. From 2011 to 2020, researches have been focused more on how climate change affects industrial suitability and the transition from ecological resources to asset management techniques instead of limited to the ecological constraints associated with resource carrying capacity. In China, the research direction in this field is affected by policy initiatives and pioneering foreign researches. From 1992 to 2010, the researches were focused more on optimizing and adjusting the rural industrial structure and constructing an ecological safety system, based on Wooden Barrel Theory, by accurately quantifying the elasticity of different ecological resources, defining the limit condition of specific industries that do not damage the restoration capacity of ecosystem. In recent ten years, as the ecological effect of industrial development constraints has become significant, the concept of "ecological constraint" has been formally accepted, and the focus of researches is no longer limited to "ecological suitability" one-way analysis. At present, "clarity and measurement, coordination and capitalization, policy and the bottom line" have become the focus of ecological constraints related to the development of rural industries. It is important to develop the industry as quickly as possible without sacrificing the resilience of the ecosystem. Finally, the contents, methods, and research results on the suitability of rural industries under the constraints of ecological security in the past 30 years are analyzed, and the insufficiency of relevant research in China and the future development directions are proposed.

In this study, statistical data, research literature, and survey data were used to examine the overall situation of rural and township development and resources and environment in Northwest China. The characteristics of the stress caused by rural and township development on resources and environment and the main contradictions in typical areas were summarized. Also, a path for the coordination between rural and township development and resource and environment is proposed. The results show that:(1) Considering the overall situation and development trend of the region, the population in Northwest China is decreasing, the agricultural productivity is increasing, the construction of environmental protection facilities in rural and townships is lower than the national average level, the per capita water resources is low and the agricultural water supply is in shortage, the use of chemical fertilizers, plastic films and pesticides is increasing,while the high-quality cultivated land area is decreasing; (2) Considering the regional stress characteristics and the main contradictions, the water resource supply is a bottleneck, and soil salinization in irrigated agricultural areas has been intensified; the overall carrying capacity of resources and environment in rural and townships is relatively low, and agricultural land as reserve resource is insufficient. Extreme climate and overgrazing in alpine pastoral areas have led to the reduction of grassland yield, serious degradation of grassland, as well as a noticeable contradiction between the amount of livestock and the area of grassland; industrial structural problems in rural and townships are significant, and regional functions are weakened as a whole. Over exploitation of mines in Qinling protection zone has resulted in serious water and soil pollution, awareness of environmental protection in rural and townships is weak, and the construction of environmental protection facilities lags behind. (3) From the perspective of coordination path, innovative technologies should be applied to agricultural activities, and their utilization efficiency should be improved; water-saving agricultural practices should be developed in accordance with local conditions; the industrial structure of alpine pastoral areas should be adjusted, and a reasonable planning should be performed to ease the contradiction between grassland and livestock; the management and control of mining areas should be strengthened, and attention should be paid to ecological restoration; industrial structure transformation should be reinforced. The local government should establish a mechanism to strengthen the pollution source control and apply multi-faceted investments to control non-point source pollution in rural and townships.

To explore the changing characteristics of the ecological carrying capacity and figure out the key influencing factors of sustainable development of the Renhuai City, the per capita ecological footprint, per capita ecological carrying biocapacity and ecological surplus/deficit from 2010 to 2018 were analyzed based on the ecological footprint model. Furthermore, four key indexes, including ecological footprint index, ecological stress index, corresponding quotiety of ecological and GDP's ecological footprint, and six factors were applied to study the sustainable development status and influencing factors of Renhuai City. Results show that the Renhuai City has been in status of ecological deficit. Both the per capita ecological footprint and the per capita ecological carrying capacity presented a similar trend of decreasing first and then increasing. The per capita ecological footprint increased from 1.5 hm² to 1.8 hm², with an increase of 20% during research period. The per capita ecological carrying capacity increased by 14.89%, from 0.94 hm² to 1.08 hm²; the per capita ecological footprint and per capita ecological carrying capacity of the Renhuai City were mainly contributed by cultivated land and woodland, which accounting for 81% of the per capita ecological footprint and 79% of the per capita ecological carrying capacity, respectively. The ecological footprint index was between -76.96% and -59.22%, and the ecological pressure index was ranged from 1.59 to 1.77, as in view of the relevant evaluation standards, the Renhuai City's ecological footprint index and ecological stress index was in the status of 3rd grade and the 5th grade, suggesting there exists great challenges in regional sustainable development. In addition, the main driving factors impeding the Renhuai City's ecological footprint were population size, featured industries, and pollutants emissions. These results of the research are helpful to discover the internal connection between the development of featured industries in Renhuai City and the ecological footprint, and can provide theoretical basis for the sustainable development patten of similar areas.

As China's rural revitalization strategy progresses, the development of rural townships is in a transition period of high-quality social and economic expansion. With its focus on Jiangning Township in Nanjing, the present study examined the relationship between socioeconomic development and water resources carrying capacity of rural and townships as they undergo rapid urbanization. A combination weighting method was adopted to identify the key influencing factors of water resource carrying capacity of townships. At the township scale, the five aspects of spatial control, water resources utilization, ecological environment governance, livability, and economic development were examined; An evaluation index system was constructed and principal component analysis was applied to determine the water resources carrying capacity of representative townships. It was found that the water resources carrying capacity of the representative townships showed a fluctuating trend from 2013 to 2018; the main influencing factors of the water resources carrying capacity during that period were the level of ecological and environmental governance, spatial control, and urbanization. It has been observed that water resources utilization level is also an important factor toward ensuring the water resources carrying capacity in the investigated townships. The results of the study can serve as a reference for similar townships in China as they aim to achieve coordinated economic development and utilization of water resources in the process of urbanization.

Ecosystem service is the bridge connecting nature and human well-being. To meet mankind's demand, the ecosystem endures to provide products and services through ecological functions. Based on the analysis of global research progress on ecosystem service, human well-being, and their relationships, this study summarizes the associations and classifications of ecosystem services with human well-being and explains relationship forms, and relationship evaluation methods. The study emphasized that the scientific research on the relationship between ecosystem service and human well-being should be intensified and well directed towards serving policy-making and management in future. Through a comprehensive review, it provides a strong support for sustainable development strategies such as ecosystem management, and poverty alleviation.

The inertia of green manure planting behavior of farmers can guarantee the achievement of the government's agricultural environment goals without increasing the government's financial burden. Using the survey data of 1 217 households in the provinces of Hunan, Jiangxi, Guangxi, Anhui and Henan, the influence of the ecological compensation policy on farmers' green manure planting behavioral inertia was analyzed by applying the propensity score matching (PSM) method. Results show that the ecological compensation policy significantly promoted the generation of behavioral inertia. Compared with those who did not receive ecological compensation from the government, the probability of green manure planting behavioral inertia of farmers who received ecological compensation increased by 21.8%. Ecological compensation can stimulate the generation of behavioral inertia through two pathways, one is "ecological compensation→income effect→behavioral inertia", and the other is "ecological compensation→environmental knowledge→behavioral inertia". In addition, the younger, well-educated, large-scale farmers and farmers with high-quality cultivated land are more likely to develop the behavioral inertia. Therefore, on the premise of reshaping the ecological compensation standard and compensation modes as well as fully considering the heterogeneity of farmers' endowment, the idea of constructing the inertia generation mechanism of green manure planting behavior was put forward to promote the sustainability of farmers' behavior.

Since the 21st century, the number of wild bird species in China has been increasing constantly. From 1947 when the publication of "Checklist of Chinese Birds" to 2018, new bird records have been growing rapidly. However, the spatial and temporal distribution of new recorded birds is unclear. The classification and distribution of these records are summarized and the reasons for the appearance of these new recorded bird species are also explored. The results show that the new recorded bird species are mainly distributed in north China (including Xinjiang, Inner Mongolia and Heilongjiang), east coast and south coast. Inner Mongolia Autonomous Region recorded the highest number of new bird species, followed by Guangdong Province, while Shanghai and Tianjin recorded the least. Combined with the data of the total number of birds, habitat types in each province and the new recorded bird species from 2000 to 2018, we found that the newly recorded bird species had a significant positive correlation with cultivated land, woodland, grassland and water area.

In order to explore the dynamics of CO₂ flux exchange and its regulating mechanism of mangrove in Guangxi, the CO₂ flux data and the meteorological data of sandy mangrove recorded by the eddy covariance system at the mangrove ecological observation and experiment station in Beihai in 2019 were utilized to analyze the dynamics of net ecosystem carbon exchange (NEE) and its response to meteorological factors. The results suggest that the diurnal variation of NEE on average followed a U-shape pattern in Guangxi. The carbon sink reached the maximum in February and the minimum in June on the monthly scale. On the seasonal scale, the maximum NEE occurred in autumn, followed by spring, winter, and summer. The cumulative monthly NEE reached the maximum of -45.23 g·m^-2·mon^-1 in November and the minimum of -16.95 g·m^-2·mon^-1 in July. The total amount of NEE, ecosystem respiration, and gross primary productivity (GPP) were -386.68, 862.49, and -1 249.18 g·m^-2·a^-1, respectively, which were lower than that in the mixed mangrove in Fujian and Guangdong. The dominant factor of direct influence on the net ecosystem exchange was the photosynthetically active radiation, and that of indirect influence was vapor pressure deficit. Precipitation was the limiting factor of net ecosystem exchange.

Using a greenhouse vegetable base in Zhijin County, Guizhou Province as an example, simple correlation, principal component and path analysis were applied to study the characteristics of Cd accumulation in vegetables of a greenhouse vegetable base in a high Cd geological background area. The main sources of soil Cd, its phytoavailability and its correlation with soil pH, soil organic matter (SOM), alkaline nitrogen (NA) and other basic soil physicochemical properties were also studied, and the main controlling factors of soil Cd bioeffectiveness were analysed. The results show that the Cd content in the topsoil of 75.32% of the sites of the base was greater than the background value of soil Cd in the topsoil of Guizhou Province (0.659 mg·kg^-1), and the bioaccumulation of Cd in greenhouse vegetables were in the order of cabbage > tomato > cowpea, with none of the three vegetables exceeding National Food Safety Standard (GB 2762-2017). Correlation coefficient (R=0.785) between Cd contents in vegetable fruits (Cd_p) and the content of available Cd in soils (Cd_A) was higher than that (R=0.508) between Cd_p and total Cd (Cd_T), implying that Cd_A is better than soil Cd_T for assessing Cd contamination in vegetable fruits and for predicting the safety risk of vegetable production. The content of Cd between topsoil and subsoil using independent-samples t test showed that the main source of Cd in greenhouse soils was weathering of the parent material in high Cd geological background area, and its high Cd content and high nitrogen application are direct and indirect factors for the increasing of the biological effectiveness of soil Cd. Cd_A was correlated significantly with Cd_T, pH and available nitrogen (P<0.05), but not with soil organic matter (SOM), available phosphorus and available potassium. Therefore, cowpea can be considered for the development of facility vegetable cultivation in areas with high Cd geological background, and the amount of N fertilizer application should be strictly controlled to ensure the safety of the "vegetable basket".

Three-dimensional fluorescence spectroscopy (3DEEM) and parallel factor analysis (PARAFAC) were used to study the composition, profile distribution characteristics and main sources of dissolved organic matter (DOM) in the interstitial water of sediments in the littoral zone of Lake Chaohu. The results show that DOM in interstitial water contained three fluorescent fractions, including humic-like fraction C1 (275 nm, 365 nm/467 nm), humic-like fraction C2 (330 nm/407 nm) and tyrosine-like fraction C3 (275 nm/319 nm). In terms of spatial pattern, the mean value of DOM fluorescence intensity in the pelagic zone was (0.432±0.306) RU, which was lower than the mean value of DOM fluorescence intensity in the near shore zone of (0.583±0.478) RU, while the mean value of fluorescence intensity in the near shore zone was greater than that in the center of the lake, and the fluorescence intensity showed a decreasing trend with depth in the vertical profile at each point. In terms of time pattern, the mean value of DOM fluorescence intensity in summer was (0.390 0±0.301) RU, less than that in winter[(0.584±0.453) RU];In addition, the DOC concentration in the nearshore zone was higher than that in the pelagic zone, the DOC concentration in the pelagic zone was higher than that in the lake center, and the DOC concentration in all sections in winter was higher than that in summer; The DOC concentration first increased, then decreased rapidly with the increase of sediment depth, and remained stable below 10 cm layer of sediment-water interface. The humification index (HIX) in winter was higher than that in summer, and the fluorescence index (FI) and biogenic index (BIX) indicated that DOM in interstitial water was influenced by both endogenous biogenic sources and terrestrial sources of exogenous pollution, and was more influenced by endogenous biogenic sources. This study can provide certain references for the water environment management and non-point source pollution control in the littoral zone of Lake Chaohu.

Precise predictions of spatial variability of soil organic matter and total nitrogen are largely depended on methods and spatial scales of the interpolation. In this study, two spatial scales including plot scale (50 m×50 m, 80 soil samples) and farm scale (1 000 m×1 000 m, 100 soil samples) were selected from nearly harvesting field of summer maize in the northern part of Huanghuaihai Plain. And two interpolating methods including ordinary Kriging and artificial neural network based on radial basis function (RBF) were compared to explore more accurate spatial variations of soil organic matter and total nitrogen content in the study area. Results of nugget to sill ratio (0.448-0.637) showed moderate spatial variations of both spatial scales with contents of soil organic matter and total nitrogen ranged from 8.39 to 20.59 g·kg^-1 and from 0.31 to 2.90 g·kg^-1, respectively. Spatial variations of soil organic matter and total nitrogen presented decreasing trends with higher contents distributed along the diagonal from northwest to southeast and lower contents distributed around the edges at farm scale, in contrast, higher and lower contents respectively located in northeast and southwest parts at plot scale. Concerning root mean square error (RMSE), average absolute error (MAE) and average relative error (MRE) of interpolation by artificial neural network based on RBF, smaller values indicated better predictions of spatial variations at plot scale rather than at farm scale. Without smoothing effect, increased R² and decreased errors proved better performance of artificial neural network based on RBF rather than ordinary Kriging in modeling spatial variations of soil organic matter and total nitrogen at each spatial scale. It indicates that artificial neural network based on RBF is the better interpolating method for predicting spatial variations of soil organic matter and total nitrogen in this study.

In order to establish monitoring method for ammonia emission in livestock enclosures and provide technical support for accurate calculation of ammonia emission in livestock enclosures, the natural ventilation pens of typical large-scale pig farms in Yangtze River Delta were taken as research object, and the influence of sampling efficiency, time and frequencies based on the ammonia monitoring standard method were discussed. The results show that the sampling efficiency was greater than 90% when the sampling time was more than 4 minutes (4 L collected gas) by the salicylic acid method, and there was no significant difference in the content of ammonia obtained by different sampling times (4, 20, 40 and 60 min). The relative error of hourly sampling frequency and 90% of cumulative frequency increased with the decrease of sampling frequency. The relative error in summer (with average daily temperature of 25-35℃) is significantly higher than that in winter (with average daily temperature of 0-10℃). Similar to the hourly sampling frequency, the average relative error of daily sampling frequency increased with the decrease of sampling frequency. In order to carry out ammonia monitoring in large-scale pig farms in the Yangtze River Delta, it is suggested that the sampling frequency should be no less than 4 times·h^-1 and increase to 6 times·h^-1 at 6-7 o'clock and in the afternoon in summer, and the daily sampling frequency should be no less than 12 times·d^-1 as well. While in winter, the sampling frequency should be 2 times·h^-1 and no less than 4 times·d^-1.