Research Status, Hotspots, and Trend Analysis of the Rural Living Environment Upgrade in China from 1992 to 2022: A Bibliometric and Narrative Review Analysis

Abstract

The rural living environment is the foundation of rural ecology and rural residents’ life, and the quality of the rural living environment is directly related to the green and low-carbon development of rural areas and the physical and mental health of rural residents. This article aims to grasp the current situation and of rural living environment improvement research and its various research hotspots, explore research frontiers and trends, and provide crucial theoretical guidance for rural living environment improvement research by searching and analyzing China’ national knowledge infrastructure database (CNKI). The article adopts CiteSpace6.2 bibliometric software and the narrative review method to analyze 1349 papers on rural living environment upgrading in CNKI from 1992 to 2022. Among them, the narrative review collects and analyzes the relevant information on rural living environment improvement to provide the background and content for the relevant arguments. It is found that (1) the rural living environment governance policies can be divided into four stages, namely, the initial stage, policy exploration, policy enhancement, and policy deepening, with the policy system continuously maturing and the governance content becoming clearer; (2) research hot topics can be summarized as research on the connotation and governance model of the rural living environment, research on development status, research on effective evaluation and influential factors, and research on treatment model and technology involving interdisciplinary integration development; (3) the rural living environment upgrade research history can be divided into three periods: before 2004, which was the start-up stage, thus the number of publications was relatively small, and core topics included the transformation of rural toilets and rural domestic sewage treatment; 2004–2017, which is the expansion stage, thus the total amount of literature is increasing yearly, and the research topics are gradually enriched; after 2018, which is the the mature development stage, further clarifying the key tasks of rural living environment upgrades; (4) in the future, it is necessary to keep the focus on research in the four key areas, deepen the research on governance connotation, influential factors, and effect evaluation, explore the typical models of rural living environment construction in China, and provide research guidelines and practical decisions for rural living environment governance.

1. Introduction

Since the reform and opening up in 1978, economic development has become China’s long-standing and rigorous goal. However, the rapid growth of the economic scale has been accompanied by the considerable resource, environmental, and ecological cost of rapid and large-scale industrialization and urbanization in China [1,2]. These problems are concentrated in the deterioration of the rural ecological environment. The reason for this is that China has long faced a dichotomy between urban and rural ecological environments, and the government’s environmental protection policies are mainly tilted toward the cities, neglecting the development of the rural ecological environment, thus resulting in the increasingly severe environmental pollution in China’s vast rural areas [3,4]. The pollution in China’s rural ecological environment mainly comes from three sources: rural living pollution, agricultural production pollution, and industrial pollution, involving agricultural non-point source pollution, water pollution, living waste pollution, and industrial transfer pollution [5]. In terms of pollution sources, rural ecological environment pollution includes the pollution of the living environment related to rural residents’ life, namely, rural living environment pollution [6]. The rural living environment includes the natural and human environment that is closely related to the essential life and development of villagers and does not directly involve issues related to agricultural production [7]. In order to solve the problem of the rural living environment in China, as early as 2004, the government proposed to “strengthen rural infrastructure construction and make up for the shortcomings of the hard living environment”; especially since the implementation of the “Three-Year Action Plan for Rural Living Environment Upgrade” in 2018, the quality of the rural living environment has been significantly improved. Therefore, in order to comprehensively improve the quality of the rural living environment, the “Five-Year Action Plan for Rural Living Environment Upgrade (2021–2025)” specifies the critical tasks in the field of rural living environment upgrade in the next five years, covering such key areas as rural domestic sewage, rural living waste, rural toilet renovation, village appearance improvement, and other key areas of concentration [8].

With the continuous promotion of rural living environment upgrade work, China’s rural living environment continues to improve. According to survey data, by the end of 2020, the rural domestic sewage rate reached 28%, the rural living waste collection and disposal system has covered more than 90% of administrative villages nationwide, and the rural sanitary toilet penetration rate reached more than 68%. More than 95% of villages have carried out cleaning actions to significantly improve village appearance [9,10]. However, there are still practical problems, such as uneven governance between regions and inadequate governance of living environments in certain areas. In addition, due to the wide distribution of rural population, and complex and diverse geographical environment, villagers’ habits are different, and the degree of pollution in rural living environments varies. First, rural living sewage is discharged freely, and the sewage treatment rate is low. In some poor areas and scattered villages in China, villagers directly discharge living sewage into rivers due to the lack of sewage treatment facilities. According to the data of the “Second National Pollution Source Census Bulletin”, in the rural domestic sewage pollutant discharge, the chemical oxygen demand is 4,996,200 tons, ammonia nitrogen is 24.50 million tons, total nitrogen is 446,500 tons, total phosphorus is 36,900 tons, and animal and vegetable oil is 19.80 million tons. However, in 2020, only 28% of administrative villages nationwide treated domestic sewage, and the chemical pollutants contained in living sewage seriously affected the living environment of villagers and the surrounding water bodies [11,12]. Second, it is difficult to collect classified domestic waste, and the resource utilization rate is low. With the transformation of rural production and consumption structure, a large number of types of domestic waste with complex chemical compositions are produced. According to the per capita generation of 0.80 kg/day, the amount of rural living waste generated in 2020 is about 165 million tons [13]. However, about 1/4 of domestic waste in China is not collected and treated, and most of the rural living waste treatment in rural areas is still mainly mixed landfill and incineration, which not only brings serious secondary pollution to water, soil, and air but also seriously threatens human health [14]. Third is pit privy pollution. Villagers still use traditional pit privy or open-air toilets in remote and backward rural areas such as the northeast and west of China. The above-mentioned toilets are not convenient to clean and easily breed mosquitoes and bugs, spread diseases, and cause great pollution to the surrounding water and soil environment [15]. Fourth, the ecological problems of village appearance are prominent. In some rural areas of China, no attention was paid to ecological protection, blindly imitating the urban living environment construction model, engaging in large-scale demolition and construction, and destroying things that reflect the spiritual and cultural values of the countryside. Moreover, the problems of “rural hollowing” and population aging are extremely serious, which seriously damage our countryside’s population balance and ecological balance [16].

Therefore, rural living environment pollution has seriously damaged the balance between economic, social, and ecological systems and has become an urgent problem in China’s rural ecology. According to the 7th National Census results in 2021, the country’s rural population totaled 509.79 million people, accounting for 36.11%. With 1/3 of China’s population still living in vast rural areas, improving the living environment of the rural population is directly related to the fundamental well-being of more than 500 million rural residents in China and the environmental improvement of 94% of the country’s land area [17]. It is of great significance to the comprehensive promotion of rural revitalization. Based on this, this study conducted a systematic review of the research literature in the field of rural living environment improvement from 1992–2022 using CiteSpace based on bibliometric and narrative review analysis methods. This study includes the following objectives: (1) using narrative reviews to sort out domestic and foreign research dynamics in rural living environment improvement; (2) analyzing the literature quantity, the main authors, and their research fields; (3) discussing the main hot topics in the field of rural living environment upgrades in China based on the statistics of top keywords through a cluster analysis of co-occurring keywords; (4) systematically delineating research phases; and (5) identifying research trends. Finally, it is hoped that the research results can provide a theoretical basis and a reference for decision-making in the future improvement of the rural living environment in China. Then, the rest of the study is organized as follows: Section 1 introduces the specific research questions; Section 2 reviews the relevant literature in the field of rural living environment improvement research; Section 3 describes the methodology of data collection and analysis; Section 4 is the research status analysis; Section 5 gives the research hot topics and the division of research phases; Section 6 identifies the research trends and limitations; and Section 7 draws conclusions and recommendations.

2. Literature Review

2.1. Research on Rural Living Environment Improvement in Developed Countries

The systematic study of the rural living environment began in the 1950s with the concept of “ekistics” proposed by the Greek scholar Doxiadis [18]. In the 1960s, when these countries were facing the stage of rural–urban transition, rural settlement types and settlement forms drew the attention of scholars. By the 1980s, the agricultural production function in Western countries gradually transformed to modern functions such as leisure resorts and ecological environments, and the transformation of rural living space, rural environmental pollution, and residents’ physical and mental health was also widely discussed [19,20]. From the end of the 20th century to the beginning of the 21st century, as the process of “reverse urbanization” accelerated, community adaptation, the impact of urban–rural migration on the rural environment, and rural living environment management became hot topics of discussion [21]. Currently, the social and spatial patterns of rural communities in Western countries have changed significantly, and the research on the rural living environment is based on the background of leisure consumption [22]. Since the gap between urban and rural areas in Western developed countries is relatively small, the research on rural living environment is mainly focused on the living environment, living subjects, living space, and urban–rural migration [23].

2.2. China’s Rural Living Environment Improvement Study

China’s rural living environment governance has experienced more than 70 years of development, and by analyzing rural living environment governance policies and landmark governance events, rural living environment governance can be divided into four evolutionary stages: policy gap, policy exploration (1978–2003), policy enhancement (2004–2017), and policy-deepening (2018–present). Figure 1 illustrates the policy change of rural living environment.

First, in the initial stage (1949–1977), which was before the reform and opening up, the country focused on industrial development and urban construction, holding the development concept of “pollution first, treatment later”, and sacrificing the rural ecological environment for urban industrial development [24]. In 1952, a nationwide patriotic sanitation campaign was launched, covering mass sanitation campaigns such as the “two management, five changes” campaign and the elimination of four pests [25]. In the rural areas, the “two management” and “five changes” campaign were carried out. Two management refers to the management of water for living and the management of human and animal excrement, while five changes are the specific operations of two management, including “five changes”, which are improving wells, toilets, stables, stoves, and the environment. During this period, the patriotic sanitation campaign was carried out to reduce the problem of “dirty” in the rural living environment, which led to the health of the public.

Secondly, the policy exploration stage (1978–2003), from 1978 after the reform and opening up to 2003 belongs to the exploration period of the rural habitat environment policy system, but the policies and actions specifically for the rural habitat environment are not proposed independently but are embedded in the rural environment policy system. During this period, the pollution problem of rural living environment exploded intensively due to the transfer of industrial pollution to rural areas brought by rapid urbanization on the one hand, while on the other hand, rural enterprises also developed rapidly and the scope of pollution from rural enterprises spread rapidly. In addition, the problem of rural living waste pollution, human, and animal waste discharge gradually intensified, seriously affecting the living environment of rural residents [26]. In response to these problems, in 1979, China promulgated the “Environmental Protection Law of the People’s Republic of China” for the first time as the basic law of environmental protection in China. In 1993, the State Council enacted the “Regulations on the Administration of the Planning and Construction of Villages and Towns”, which included the construction of village roads, water supply and power supply infrastructure, and emphasized “strengthening greening, village appearance and environmental sanitation”. In 1998, the State Environmental Protection Administration of China proposed to focus not only on agricultural pollution control, but also on environmental pollution control of rural residents’ living environment, gradually focusing on individual areas such as water, toilet, and biogas energy improvement in rural areas [27].

Third, in the policy upgrading stage (2004–2013), the task of governance gradually shifted from urban habitat management to rural habitat management, and China successively put forward the policies of new rural construction and beautiful countryside centering on rural development, etc. In 2004, the government proposed strengthening rural infrastructure construction, making up for the shortcomings of the hard habitat environment, such as water, electricity, and road construction, and increasing the construction of clean energy in rural areas [28]. In 2005, the State Council proposed the construction of a new socialist countryside, with specific requirements for a civilized countryside and clean village appearance in terms of rural habitat management. In 2013, the Ministry of Agriculture officially launched the creation of a “beautiful countryside”, and the fourth is the policy-deepening stage (2014–present), in which the government invested many special funds for rural sewage treatment, rural road construction, housing renovation, etc. [29].

Fourth, the policy-deepening stage (2014 to present), during which the policies on rural habitat environment governance are more concentrated than in previous stages, and the policy system is continuously deepened, especially after the rural revitalization strategy was proposed, the number of rural habitat environment governance policies has been increasing, and the content of governance has become more transparent. In 2014, the State Council issued the “Guiding Opinions on Improving Rural Living Environment”, marking the independent emergence of rural habitat environment policies. The document pointed out that by 2020, rural residents will have significantly improved primary living conditions such as housing, drinking water, and travel, focused on the treatment of rural garbage and sewage, promoted the conversion of rural households into toilets, and rectified the phenomenon of private construction and occupation of rural roads [30]. In 2018, the Ministry of Agriculture and Rural Affairs issued “Three-Year Action Plan for Rural Living Environment Upgrade”, which further clarifies that village cleaning actions and greening and beautification actions should be carried out from rural living waste, household waste, toilet feces, village appearance, and village planning. In addition, the policy content of this period also continues to refine. For example, in 2019, the Ministry of Agriculture issued a policy document for rural living waste governance: “Guidance on Promoting Rural Living Waste Governance,” making clear provisions for rural living waste and heavy pollution smelly water treatment. In 2021, the State Council issued the “Five-Year Action Plan for Rural Living Environment Upgrade (2021–2025)”, which focuses on the four critical tasks of rural living waste, household waste, toilet renovation, and village appearance improvement, showing the characteristics of concentrated improvement [31]. In 2023, “Document No. 1” proposed the construction of the beautiful countryside as an upgraded version of the beautiful countryside construction, emphasizing the importance of reflecting rural culture, rural style, and other spiritual civilization construction.

Overall, compared with Western developed countries, due to the large gap between urban and rural development in China, the research presents the development trend of living environment–urban living environment–rural living environment–special area living environment. Although there have been some review analyses of the current status of research in this field, there is a lack of systematic research on the historical context, critical areas, and frontier dynamics of rural living environment and environment improvement from a bibliometric perspective. According to the current policy requirements of rural living environment upgrade, it is necessary to review the history of rural living environment upgrade research, summarize the research results, better promote rural living environment upgrade based on previous research, and fill in the shortcomings and weaknesses in the process of governance. Therefore, a new research perspective and analytical framework are needed to re-examine the research history of rural living environment upgrades. Based on this, the article uses CiteSpace bibliometric visualization software to explore research hotspots from the perspective of rural living environment upgrade as a whole and from the perspective of four key tasks, namely, rural domestic sewage treatment, rural domestic garbage treatment, rural toilet renovation and village appearance improvement, respectively. At the same time, the traditional literature review method is combined to sort out the historical lineage of rural living environment upgrade research to make a judgment on the future development trend.

3. Materials and Methods

3.1. Data Sources

This study selected Peking University Core Journals, Chinese Social Sciences Citation Index (CSSCI), and Chinese Science Citation Database (CSCD) source journals from the CNKI database as data support, first searched with the subject terms of rural living environment and rural living environment, and obtained a total of 421 pieces of literature. In order to ensure the comprehensiveness of the literature sources and the reliability of the result analysis, the four key tasks of rural living environment upgrade stipulated in the “Five-Year Action Plan for Rural Living Environment Upgrade (2021–2025)” were referred to as the subject terms of this study. The search terms “rural/village living environment”, “rural domestic sewage”, “rural living waste”, “rural toilet renovation,” and “village appearance” were searched as subject terms [32]. The time zone of the search was from January 1992 to December 2022. In order to further ensure the rationality and accuracy of the selected literature, the literature that was not related to rural living environment upgrade and its main governance tasks was excluded; finally, 1349 valid documents were obtained.

3.2. Research Methods

The current study employs bibliometric methodology to analyze the data. Bibliometric analysis is a subdivision of library and information science that employs mathematical and statistical techniques to quantitatively depict, evaluate, and forecast academic status and developmental trends. Its prominent advantages include objectivity, quantification, and the ability to model macroscopic studies. The bibliometric approach is used to dissect the descriptive features of a variety of journals, encompassing the quantity of publications, types of literature, publication years, page numbers, and impact factor trends. Utilizing this method, we can conduct a thematic analysis, hotspot analysis, and research trend analysis of the Chinese rural residential environment remediation literature over the past three decades in a more intuitive manner. Given the characteristics of the dataset in this study, CiteSpace was ultimately selected as the most suitable software. CiteSpace is an application that uses mathematical and statistical methods to visually present scientific research results and literature dynamics, developed by Chinese scholar Professor Chaomei Chen. The main functions of CiteSpace include keyword co-occurrence analysis, clustering analysis, and mutation detection. The keyword co-occurrence analysis is a high degree of condensation of the article content. CiteSpace6.2 can count the keywords with high word frequency from tens of thousands of documents, which can accurately find the research hotspots of rural living environment improvement. Keyword clustering analysis is based on keyword co-occurrence to cluster knowledge mapping analysis and explore the research class clusters and structural features in the field of rural habitat improvement. Keyword occurrence detection can reflect the importance of a keyword in that period and predict the future research direction. Specific steps are as follows: conducts a co-occurrence analysis of keywords in rural living environment upgrade research by CiteSpace bibliometric software [33]. Then, keyword co-occurrence analysis was conducted in four areas: rural domestic sewage treatment, rural living waste treatment, rural toilet renovation, and village appearance improvement, to explore the high-frequency keywords and research hotspots in specific areas. Finally, a cluster analysis was conducted for the rural living environment upgrade, forming cluster tags and their corresponding keywords. The study attempts to present a comprehensive picture of rural living environment upgrade research from 1992 to 2022 to provide theoretical guidance and practical decisions for the in-depth development of rural living environment upgrade research.

4. Current Status of Rural Living Environment Research

4.1. Literature Quantity Analysis

4.1.1. Total Issuance Trend

The fluctuation in the number of publications is closely related to policy orientation. It can also reflect the degree of attention paid to this field by the academic community at different stages of time. As shown in Figure 2, since the exploration of the concept of rural living environment was formed in 1992, the annual number of publications in the period of 1992–2003 was about two; in 2004, the government proposed to “strengthen rural infrastructure construction and make up for the shortcomings of the infrastructure construction for living environment upgrade”, and the number of papers increased rapidly; in 2018, the government proposed the “Three-Year Action Plan for Rural Living Environment Upgrade”, and the number increased further; and by 2021, the number of papers published was close to 120. Notably, there was a slight fluctuation in the number of publications in 1995, reaching 34 articles. It was found that from 1992 to 1995, a nationwide survey study on rural toilets and the fecal matter disposal method was conducted in China, covering 31 provinces, cities, and autonomous regions. The survey included the types of household toilets, the prevalence rate of sanitary toilets, and the treatment methods of fecal matter, which were published in the Journal of “Health Research”, respectively, further indicating the early study on rural toilet renovation.

4.1.2. Four Major Tasks Issuing Trends

From the viewpoint of the four key tasks (Figure 3), the trends of rural domestic sewage treatment, rural living waste treatment, rural toilet renovation, and village appearance improvement are largely synchronous and have similar evolutionary trends to the total number of articles issued, all of which began to increase rapidly in 2004. The number of articles on rural domestic sewage treatment is the highest (669), followed by rural living waste (225), then rural toilet renovation (135), and village appearance (44). It can be seen that the existing research mainly focuses on the treatment of domestic sewage, and there is not enough research on how to improve village appearance.

4.2. Statistical Analysis of Subject Areas

The disciplinary distribution of rural living environmental remediation research has a wide range of fields and involves a multidisciplinary cross-fertilization development dynamic. Figure 4 summarizes the distribution of the primary disciplines involved in the rural living environment and environment governance research literature, with environmental science (58%) and the field of agricultural economics (11%) as the primary research disciplines, followed by public health and preventive medicine (8%), urban and rural planning (7%), urban economics (6%), and agricultural resources and environment (1%). It was found that the relevant contents of rural living environment and environmental governance research are interdisciplinary, and the research contents and research methods of a single literature often involve multiple disciplines. Thus, the complex disciplinary attributes of the rural living environment and environmental governance research field are very obvious.

4.3. Highly Productive Authors and Their Research Areas

Statistics on the main authors of publications can reveal the core authors who explore the field in greater depth and their main research areas and directions. Statistically, 15 authors have published seven or more articles in rural living environment improvement research. Among them, Lv Xiwu, Li Bohua, Fu Yanfen, and Li Xudong have accumulated more than ten articles, and their research fields and directions are mainly environmental science and resource utilization, etc., which are closely focused on rural domestic sewage treatment. Secondly, the research fields of Yu Fajian, Dou Yindi, Jia Yajuan, and other high-yielding authors concern the agricultural economy, mainly focusing on the current situation of rural living environment development and the governance mode, as shown in

Table 1. Highly productive authors and their research areas.

No.	Author	Publications	Year of the Earliest Publication	Main Research Field and Direction
1	Li Bohua	14	2007	Environmental science and Resource utilization
2	Fu Yanfen	12	2009	Agricultural economy
3	Li Xudong	11	2005	Environmental science and Resource utilization
4	Yu Fawen	10	2005	Environmental science and Resource utilization
5	He Shaolin	9	2018	Agricultural economy
6	Zheng Xiangqun	9	2005	Environmental science and Resource utilization
7	Zhou Qi	8	2019	Agricultural engineering
8	Xia Xunfeng	8	2005	Environmental science and Resource utilization
9	Li Xianning	8	2012	Chemistry; Organic chemical industry
10	Huang Xiangfeng	8	2007	Environmental science and Resource utilization
11	Huang Zhiping	8	2006	Biology
12	Dou Yindi	7	2014	Agricultural basic science
13	Zhao Minjuan	7	2012	Agricultural economy; Travel
14	Jia Yajuan	7	2019	Agricultural economy
15	Li Bohua	7	2019	Agricultural economy

.

5. Rural Living Environment Upgrade Research Hotspots and Research Stage

5.1. Co-Occurrence Analysis of Keywords

5.1.1. Research on the Rectification and Management of Rural Living Environment

The keyword frequencies generated by importing 1349 documents with rural/rural living environments as the theme word into CiteSpace software are shown in

Table 2. High-frequency keywords for rural living environment upgrade research.

Name	Frequency	Intermediary Centrality	Name	Frequency	Intermediary Centrality
Rural	134	0.50	Fecal Matter Treatment	24	0.02
Domestic Sewage	85	0.27	Rural Toilets	23	0.02
Habitat	80	0.38	Countermeasures	22	0.05
Artificial wetland	79	0.05	Rural Sewage	20	0.04
Rural revitalization	68	0.06	Environmental Sanitation	16	0.08
Living Waste	46	0.06	Garbage classification	11	0.08
Sanitary toilet	36	0.2	Rural toilet renovation	11	0.10
Nitrogen Removal and Phosphorus Removal	33	0.04	Removal rate	10	0.04
Sewage treatment	29	0.19	Willingness to pay	10	0.04

, and the ranking is based on the frequency of keywords. First, the frequency of macro keywords “living environment” and “rural revitalization”, which are related to the topic research, are 80 and 68 times, respectively, and the research intensity is high. Next, the keywords “domestic sewage” (85 times), “living waste” (46 times), “sanitary toilets” (36 times)”, “wastewater treatment” (29 times), “rural toilets” (23 times), and “rural sewage” (20 times) all appeared more than 20 times. The frequency of these keywords related to the four key tasks of rural living environment upgrade reflects the refinement of the research content in the microscopic field of academia Lv Xiwu.

5.1.2. Research on Rural Domestic Sewage Treatment

In order to deeply analyze the research hotspots in the field of rural living wastewater treatment, 669 core documents retrieved with the theme term “rural living wastewater” were imported into CiteSpace software for keyword co-occurrence analysis. In order to capture the effective hotspots, the top 10 keywords in terms of frequency were selected by excluding such keywords as “rural”, “domestic sewage” and “wastewater treatment”. As can be seen from

Table 3. High-frequency keywords for rural household waste research.

Name	Frequency	Intermediary Centrality	Initial Year
Artificial wetland	79	0.12	2003
Nitrogen removal and phosphorus removal	33	0.12	2007
Treatment Technology	12	0.16	2008
Nitrogen removal	10	0.03	2006
Removal rate	10	0.09	2011
Biofilm	9	0.13	2001
Suggestions	9	0.07	2007
Treatment mode	9	0.03	2010
Anaerobic	8	0.02	2008
Decentralized treatment	8	0.09	2008

, the current research topics of rural domestic sewage mainly include the discussion of wastewater treatment mode and treatment technology. The term “biofilm” appeared as early as 2001, when some scholars analyzed the application of foreign biofilm technology in rural domestic sewage treatment [34]. In 2003, the most frequent keyword “artificial wetland” appeared for the first time, when some scholars proposed the use of artificial wetland technology to remove polluting elements such as nitrogen and phosphorus contained in rural living wastewater [35]. In summary, rural domestic sewage treatment research is mostly concentrated in the field of environmental science, mainly on artificial wetland treatment process, removal of pollutants such as nitrogen and phosphorus, and improvement and optimization of biofilm technology. However, there are fewer studies on rural living wastewater treatment from the social science field, and only a few scholars have studied the current situation and influencing factors of rural domestic sewage treatment [36].

5.1.3. Research on Rural Living Waste

The 225 core documents with the theme of “rural living waste” were analyzed for keyword co-occurrence. The 14 keywords with high frequency were selected by eliminating keywords similar to the theme “rural living waste”. From

Table 4. High-frequency keywords for the study of rural living waste.

Name	Frequency	Intermediary Centrality	Initial Year	Name	Frequency	Intermediary Centrality	Initial Year
Garbage sorting	12	0.19	2009	Willingness to sort	4	0.05	2020
Willingness to pay	11	0.20	2014	Environmental Health	4	0.02	2009
Disposal mode	10	0.10	2008	Leachate	4	0	2011
Separate Collection	8	0.21	2008	Current Status	4	0.03	2010
Village revitalization	7	0.06	2019	Resourcefulness	4	0.05	2009
Generation	6	0.21	2006	Composting	4	0.04	2011
Countermeasures	5	0.06	2008	Biogas	3	0.03	2016

, we can observe that the keywords “waste classification”, “classification and collection,” and “treatment mode” have the highest frequencies and high intermediary centrality and are closely related to other keywords. The keywords “willingness to pay” and “willingness to sort” are the second most frequent, with the first year of inception in 2014; in addition, important keywords in this field include “disposal mode”, “rural revitalization”, “generation volume”, “countermeasures”, “resource utilization”, “biogas”, etc., with different degrees of connection with other keywords. Four hot topics of rural living waste research were summarized by sorting out the relevant literature corresponding to the high-frequency keywords.

First, the current situation and countermeasures are explored. The current rural living waste has distinct regional and practical characteristics. Scholars have investigated the current situation of waste disposal in different regions, including the analysis of rural living waste generation and its physical characteristics [37,38], waste collection and treatment modes [39,40], and management modes [41,42]. The best disposal methods for rural living waste are also proposed according to local conditions.

Second, in the research on the waste classification governance model, some scholars have explored it theoretically, put forward the waste classification standard, let rural residents put out the classification [43], and put forward the “household collection, village collection, town transfer, county treatment” domestic waste classification governance model [38]. Nevertheless, in practice, there are still many practical dilemmas in the management of rural living waste classification in China, such as inapplicable classification standards, inappropriate classification facilities [44], insufficient coordination among participating parties, poor recycling of waste classification systems, etc. [45]. At present, the mixed landfill method is still popular.

Thirdly, in the research of rural living waste treatment technology, the current organic waste generated in rural life is mainly treated by anaerobic fermentation technology and aerobic composting technology, for inorganic waste and hazardous waste incineration technology is used for decomposition [46,47]. Some scholars have explored the performance of anaerobic fermentation of rural living waste under different combinations of fermentation conditions to produce biogas based on the principle of anaerobic fermentation, which can produce clean energy, i.e., biogas, and the fermented digestate and digestate can be used as organic fertilizer. Some scholars have also conducted composting experiments based on the principle of composting treatment by adding microbial bacterial agents to convert degradable organic matter into compostable organic matter and harmless inorganic matter that can be landfilled in situ through biochemical reactions [48,49].

Fourth, in the study of rural residents’ willingness to participate in waste management, existing research has mainly analyzed the factors influencing villagers’ willingness to participate in household waste separation and willingness to pay from the theory of rural residents’ behavior, including individual characteristics, rural residents’ cognition, institutional environment, and other internal and external factors [50,51].

5.1.4. Rural Toilet Renovation Research

In order to further refine the research hotspots in the field of rural toilet renovation and discover the high-frequency keywords, 135 core papers on the theme of “rural toilet renovation” were visualized and analyzed, and

Table 5. High-frequency keywords for rural toilet renovation studies.

Name	Frequency	Intermediary Centrality	Initial Year	Name	Frequency	Intermediary Centrality	Initial Year
Environmental Health	14	0.24	2005	Universal Access Rate	3	0.02	1995
Rural Health	10	0.24	1994	Harmless	3	0.14	2009
Schistosomiasis	6	0.04	2009	Biogas tank	3	0.34	1992
Countermeasures	6	0	1995	Household Toilet	2	0.04	1995
Feces	5	0.17	1995	Resource recovery	2	0.04	2017
Toilet availability rate	3	0.02	1995	household waste	2	0.02	2015
Public Toilet	3	0	1995	Influencing factors	2	0.02	2016

reports the high-frequency keywords of rural toilet renovation and their intermediary centrality, with keywords such as “environmental sanitation”, “excrement”, “penetration rate”, “biogas tank”, and “resource recovery” appearing more frequently. Therefore, the hot keywords of rural toilet renovation research can be summarized and condensed into four key themes: First, the keywords include “environmental sanitation” and “rural sanitation”, indicating that scholars are generally concerned about the impact of rural toilet renovation on environmental sanitation [52,53], and that rural toilet renovation is related to the health and well-being of the majority of rural residents. It is believed that research enthusiasm will continue to rise in the future. Second is the prevalence of rural toilets. As early as 1995, a large-scale survey was conducted on the prevalence of toilets and the mode of fecal matter treatment in rural areas. At that time, the technology of rural fecal matter treatment was still mainly discharged into biogas tanks [54]. Third is the harmless treatment and resource utilization of fecal matter. By 2009, some scholars proposed the harmless treatment technology of excrement to realize the resource utilization of fecal matter [55]. Since then, the academic community has been conducting innovative research around the harmless treatment technology, which has continued until now [56]. Fourth, satisfaction with toilet renovation. By 2016, with the continuous promotion of rural toilet renovation, some scholars began to research the factors affecting the satisfaction of rural residents with toilet renovation and put forward countermeasure suggestions to improve the satisfaction of using rural toilets [57].

5.1.5. Study on Village Appearance

There are only 44 valid documents related to village appearance. Combining the word frequency statistics function of CNKI and the keyword co-occurrence analysis of CiteSpace, a total of 95 keywords are obtained, among which 87 keywords have a frequency of 1. After screening, 10 representative keywords are selected for analysis, and the results are shown in

Table 6. High-frequency keywords for village appearance Research.

Name	Frequency	Intermediary Centrality	Initial Year
Rural Revitalization	6	0.24	2018
Human Living Environment	3	0.28	2006
Common Wealth	1	0	2007
Geographical Characteristics	1	0	2011
Cultural Poverty Alleviation	1	0	2018
Hollow Village	1	0	2006
Visionary Goals	1	0	2022
Distinguishing Features	1	0	2021
Realistic Problems	1	0	2022
Practical Path	1	0	2022

. The frequency and intermediary centrality of the keywords “rural revitalization” and “human living environment” are both higher, while the frequency of other keywords is 1. Further literature combing can summarize the hot topics of village appearance research into four aspects: regional characteristics, stage goals, realistic dilemmas, and realization paths.

Firstly, the study of the village landscape has obvious regional characteristics. Many scholars, through visiting and investigating villages in different regions, summarized and refined that each region should create a unique rural landscape appearance [58]. Secondly, the construction target of the village appearance at each development stage has the characteristics of the times. 2005 saw the introduction of new rural construction, and the development target of the village appearance at that time was to keep the village neat and tidy, with the problem of being “dirty and messy” as the main problem. With the improvement of the living standard of rural residents, the Central Document No. 1 of 2013 proposed the construction of beautiful countryside, and the main task of village appearance was gradually upgraded from “getting rid of the dirty and messy” to “pursuing the beauty of the countryside”. In 2018, the General Office of the State Council proposed in the “Three-Year Action Plan for Rural Living Environment Upgrade” to achieve the milestone of a neat and orderly village environment and a general increase in villagers’ awareness of the environment and health by 2020. In 2021, the “Five-Year Action Plan for Rural Living Environment Upgrade (2021–2025)” proposed to strengthen the greening and beautification of rural areas and improve the appearance of villages, and other goals [59,60]. Thirdly, at this stage, the improvement of village appearance still faces many practical dilemmas, such as hollowing out of villages, uneven supply of infrastructure, and lack of participating subjects, which has caused a large loss of manpower invested in the construction of the rural living environment. Fourth, the exploration of paths for village appearance improvement includes the integration of village culture and regional environment [61], the improvement of public goods and services supply [62], the collaborative participation of multiple subjects [63], and so on.

5.2. Keyword Cluster Analysis

To better grasp the thematic modules of rural living environment upgrade research hotspots, cluster knowledge mapping analysis was conducted based on keyword co-occurrence to explore the research class clusters and structural features in the field of rural living environment upgrade, and a total of 12 cluster labels were obtained, as shown in Figure 4, namely: #0 human living environment, #1 domestic sewage, #2 rural, #3 rural toilets, #4 countermeasure suggestions, #5 rural toilet improvement, #6 domestic waste, #7 nitrogen removal and phosphorus removal, #8 separate collection, #9 environmental sanitation, #10 artificial wetland, and #11 rural revitalization. The cluster mapping shows that the module value of clusters Q = 0.8657, which is greater than the critical value of 0.3, and the average profile value S = 0.9659, which is greater than the critical value of 0.7, indicating that the class cluster structure of clusters is significant and has high confidence for further analysis.

The above keyword co-occurrence analysis on the rural living environment upgrade and its four key tasks only analyzes the research hot topics corresponding to the high-frequency keywords, which cannot comprehensively grasp the research history in rural living environment upgrade as a whole. Therefore, it is necessary to summarize the research themes of rural living environment upgrades by combining traditional literature review methods. Thus, based on the 12 clustering tags (Figure 5) formed and their corresponding keywords, this study refines the hot research topics in this field into the following four areas.

(1)

Study on the Connotation and Governance Model of Rural Living Environment

This type of research content is the overall framework of rural living environment upgrades in the concept, connotation, and essential research throughout the entire research history of rural living environment upgrade, with the role of outline, including the connotation of rural living environment analysis and rural living environment upgrade governance model exploration. (1) The connotation of rural living environment analysis: Most of the existing literature mentions improving the rural living environment from the connotation analysis of the rural living environment, which has a certain basic role. At present, the academic community agrees that the rural living environment alone as a concept has been talked about is the beginning of the 1990s. Mr. Wu Liangyong proposed the science of human settlements. From a broad level define, the concept of the rural living environment, the academic community agrees with the definition made by Mr. Wu Liangyong, i.e., that rural living environment covers the rural human environment, social environment, geospatial environment, natural ecological environment, and artificial environment [64]. However, from a narrower perspective, different scholars, because of the differences in their disciplinary background based on Mr. Wu’s definition of the concept of rural living environment and diversified interpretations, cover disciplines such as architectural planning, ecology and environment, and human geography [65,66]. (2) Research on the governance model of rural living environment upgrade: Relevant scholars deeply investigate villages, use typical cases to dig out the potential laws of rural living environment governance, and summarize the theoretical logic behind the phenomenon. Although the focus of the governance models is different, they all emphasize the need to coordinate the functions and roles of the government, market, rural residents, and other actors in the governance process [67,68].

(2)

Study on the Development Status of Rural Living Environment Remediation

The content of such studies is time sensitive. At different times, relevant scholars have analyzed the current situation or the existing real problems of rural living environment upgrade from the macro and micro levels, respectively, and put forward diversified solutions to countermeasures. (1) At the macro level, the existing studies mainly summarize the progress of governance from an overall perspective and point out the existence of many common problems, such as inadequate policy implementation, insufficient investment in infrastructure and equipment, poor technical adaptability, and low operational management and care efficiency, and propose countermeasures to strengthen top-level design, improve infrastructure construction, and realize technical and model innovation. (2) The questionnaire survey method is mainly used at the micro level. There is a large-scale survey based on the national scale and combined with the regional characteristics of different regions through the village level and rural resident level survey content to summarize the regional rural habitat environment improvement situation. The survey contents at the village level include infrastructure supply status, environmental sanitation status, household waste and household waste generation, rural toilet renovation status, and village appearance improvement status. Yu, Fajian et al. quantified the amount of domestic sewage and household waste generated in rural areas in Eastern, Central, and Western China, and found that the overall amount of generation was increasing, and there were significant regional differences [69]. Based on a survey of 211 villages in 24 provinces, Huang Zhenhua et al. found that the problems of low coverage of household waste treatment facilities, unscientific treatment of household waste, inadequate toilet renovation, lagging road greening, and haphazard construction are still prominent [70]. The rural resident level mainly examines the specific behaviors of villagers’ participation in habitat improvement. Zhao Xia takes the rural areas of Beijing and Hebei as an example and finds that household waste is dumped and placed everywhere, and private construction of village houses and premises is still more common [71]. In addition, the summary of micro-level experience mostly focuses on improving public services and infrastructure, sound long-term management mechanisms, and enhancing villagers’ awareness of their main responsibilities.

(3)

Research on the Evaluation of Effectiveness and Influencing Factors of Rural living environment upgrade

This research theme is characterized by multi-scale research, covering the evaluation of governance effects and analysis of influencing factors in different regions and different time years, especially after the rural revitalization strategy was proposed and relevant research results have emerged. (1) Evaluation of the effects of rural habitat environment improvement. From the research scale, it can be divided into national level, provincial level, and rural resident level. The research scale can be divided into national, provincial, and rural resident levels. At the national level, Liang Chen et al. [72] constructed a rural habitat environment index system based on ecological, production, and living functions. The research results showed that the quality of the rural habitat environment in 30 provinces and cities had been significantly improved. Still, the gap between different regions tends to widen gradually. Deng Xiyue et al. [73] took Sichuan province as an example at the provincial level. They measured the evolution of rural habitat quality from 2005 to 2019. The results showed that the quality of the rural living environment gradually improved, with significant regional differences among municipalities and a spatial pattern of “high in the east and low in the west”. At the level of rural residents, the satisfaction of rural residents with the effect of rural living environment upgrading was measured by issuing questionnaires. Xu Yixin et al. [74] found through the survey that the satisfaction of rural residents with the improvement of rural living environment quality was high. Still, the participation of rural residents was low. (2) Research on the influencing factors of rural living environment upgrade: at the macro level, the improvement of the rural living environment is influenced by various factors such as natural geographic conditions, economic development level, and regional culture; at the micro level, rural residents mostly use econometric analysis to study the influencing factors of rural residents’ willingness to participate in household waste treatment and garbage classification and management [75,76].

(4)

Research on the Treatment Model and Technology of Rural Living Environment Upgrade

The academic community has specifically explored their treatment models and the application of treatment technologies around the key tasks of rural living waste treatment, rural living waste treatment, and rural toilet renovation, and in particular, the research literature related to rural living waste treatment is the most abundant. (1) Rural living waste treatment models and technologies: There are three modes of rural living waste treatment in China, namely, decentralized treatment mode, village centralized treatment mode, and into the urban drainage network mode [77]. Rural living waste treatment technology mainly includes soil percolation technology, artificial wetland technology, solar-powered sewage treatment technology, and biofilm treatment technology, etc. [78]. The differences in natural geographic conditions and topographical features lead to different treatment modes and technology selection. (2) Rural living waste treatment modes and technologies. Nowadays, many rural areas adopt the waste treatment model of “household storage, village collection, town transfer and county treatment”, which is difficult to achieve separate storage, and is unified by the government and lacks long-term funding, so some scholars propose a separate treatment model, which can realize part of the waste can be treated locally at source and improve the recycling rate [79]. The existing rural living waste treatment technology mainly includes incineration treatment, composting technology, and sanitary landfill, etc. Ren Yue et al. studied a household waste sorting and disposal technology, which can achieve a resource utilization rate of more than 90% through the biological enzyme liquefaction method [80]. (3) The model and technology of rural toilet transformation: Rural residents live in scattered areas, with a wide variety of toilet types, and fecal matter is mainly treated separately. Some scholars currently study the characteristics of sanitary toilets, such as the three-compartment fecal septic tank type the and fecal matter–urine separation type, and evaluate the effect of fecal waste treatment technologies such as anaerobic fermentation, aerobic fermentation, drying, and incineration to achieve harmless and resourceful treatment [81].

5.3. The Rural Living Environment Upgrade Research Stage

Twenty-five burst words were obtained by automatic software measurement. The red line indicates the length of time and the year in which the keyword appears. Figure 6 shows that the early scholars focused on rural toilet improvement research, with the main target of “fecal matter treatment” and “sanitary toilets”. In recent years, research has been conducted around keywords such as “rural revitalization”, “human living environment”, and “quality evaluation”. With the analysis of publications, policy evolution, and the emergent words in several stages, the evolution of research on rural living environment upgrading in Chinese academia from 1992 to 2022 can be divided into three stages.

The first stage is the initial stage (1992–2003). The academic research on rural habitat environment began at the end of the 20th century, during which the sciences of human settlement were just introduced into China. The corresponding policy system of the rural habitat environment still needs to be formed. Hence, the research on rural living environments was relatively small, and the number of publications was also small [82]. Most of the research topics are focused on the transformation of rural toilets and rural living waste treatment, and the form of research is mainly backgrounding investigation and countermeasure suggestions. Rural toilet reform research topics include the prevalence rate of sanitary toilets and biogas construction; the research topics of rural living waste include the research of artificial wetlands, biofilm, and other sewage treatment technologies.

The second phase is the expansion phase (2004–2017) years. During this period, the relationship between urban and rural areas changed and entered a stage of development in which cities backed seeding countryside and industry-assisted agriculture. The state began to focus on improving rural living conditions and living environment, and rural infrastructure construction and public services were significantly enhanced. Academics have started to pay attention to the construction of new rural areas, beautiful countryside, and rural habitat construction, and the number of articles issued has shown a rapid increase [83]. In this context, more and more scholars began to cut from the perspective of environmental science, agricultural economics, and sociology. The research content was further refined, including waste classification, toilet renovation, sewage treatment technology research, village planning, governance, etc.

The third stage is the mature development stage (from 2018 to the present). Along with the rural revitalization strategy, a series of policies on rural habitat environment have been introduced one after another, with the improvement of rural habitat environment and the improvement of rural residents’ sense of access and happiness as the focus of the work. During this period, key tasks such as “carrying out the toilet and fecal treatment, promoting rural living waste treatment, advancing rural living waste treatment in phases,” and improving the appearance of villages have been clearly defined. At present, the improvement of the rural living environment has entered the stage of centralized improvement, and “harmonious countryside” and “ecological livability” have become the new label of rural living environment [84,85].

6. Discussion

6.1. Future Research Hotspots and Trends

With an overview of the literature related to rural living environment upgrading and combining it with current policy documents is taken for an example, several key research directions are proposed for the future improvement and management of rural living environment:

(1) Focus on research in four key areas: Regarding priority tasks, there are more studies on rural living waste treatment models and technologies. It is necessary to strengthen the cross-fertilization between multiple disciplines and consider the applicability of technologies to rural residents in different regions. Rural living waste treatment should focus on the end of rural residents and understand rural residents’ willingness to separate waste. Rural toilet transformation should continue to promote the harmless transformation of toilets, fecal matter treatment technology, and rural residents’ satisfaction with toilet transformation research. The focus of village appearance research is on village planning, which requires the layout and construction of villages in different types of areas (such as plain areas and mountainous areas) according to local conditions, reflecting local characteristics and retaining the rural flavor, rhythm, and nostalgia.

(2) Explore the typical model of rural habitat construction: The construction of a rural habitat environment in Western developed countries is ahead of China. These countries have experienced the process of reverse urbanization, urban–rural migration, etc., which has led to a remarkable transformation of the rural living environment, living subjects, and living space, and the emergence of leisure consumption as a background to explore the problem of rural habitat environment. In addition, with the acceleration of China’s urbanization process, the thought of counter-urbanization has also emerged in China at this stage. In the future, to meet people’s growing material and spiritual needs, the study of rural habitat environment issues can be carried out in the context of rural leisure tourism and study tours.

(3) Deepen the research on the connotation of governance of rural habitat environment: The No. 1 document of the Central Government in 2023 pointed out that it “solidly promotes the construction of livable, workable and beautiful countryside”, and that the beautiful countryside is an upgraded version of the beautiful countryside. This countryside reflects both “external beauty” and “internal beauty”. In the future, it is necessary to scientifically grasp the connotation and characteristics of the “harmony and beauty countryside” not only to create a challenging environment of rural infrastructure but also to create a soft environment of rural culture. Therefore, the academic community should focus on the new tasks and requirements of rural social transformation and environmental changes and other factors on the connotation of rural habitat management while paying attention to the cultural atmosphere of rural society and creating harmony in multiple subjects.

(4) Focus on the impact factors and effect evaluation of rural living environment upgrading at the micro level: Keyword burst detection shows that the keywords “influence factors” and “quality evaluation” have been research hotspots in recent years and will continue in the future. Regarding the influence factors, the key factors that influence rural residents’ participation in household waste management and waste separation should be investigated from the level of rural residents, and the subjectivity of rural residents should be highlighted. Regarding the research on effect evaluation, the existing research mainly focuses on the effect evaluation of the rural habitat environment in the suburbs of cities or specific areas. With the continuous promotion of habitat improvement, the regional scope of effect evaluation should be expanded, and the quality evaluation index system should be enriched.

6.2. Limitations

There are still some limitations in this research. It is hoped that future research will address the following issues: (1) This paper takes all core journals in the field of rural living environments as a sample. However, there is a wide variety of journals on the field of rural living environments in China; therefore, some studies may not be included in this study, making the analysis incomplete. In the future, more journals from this field could be selected for further analysis or comparison. (2) This study only compares the current status of rural living environment improvement in other countries through Narrative Review. It needs to comprehensively collect relevant literature on rural living environment improvement in other countries for bibliometric analysis. In the future, we will consider the inclusion of Web of Science databases in the examination and analysis from a bibliometric perspective.

7. Conclusions and Implications

7.1. Conclusions

This article sorts out the research hotspot areas in rural living environment upgrade research and its four critical tasks, summarizes its historical research lineage and evolutionary trends, and draws the following conclusions:

(1) Conclusions from the overall perspective of rural habitat environment improvement: From the founding of New China in 1949 to the present, the policy changes in China’s rural habitat environment can be divided into four stages according to the different policy contents at each stage, namely, policy gap, policy exploration, policy enhancement, and policy deepening, and the policy system is becoming mature. From 1992, when the science of habitat environment was proposed, to 2022, the research history of rural habitat environment improvement can be divided into three stages: “start–growth–development”. In 1992, the academic community began to explore the concept and theory of rural habitat environment, and the research hotspots included “fecal matter treatment”, “rural toilet conversion”, “sanitary toilets”, etc. In 2004, the Party Central Committee proposed to “strengthen rural infrastructure construction and make up for the shortcomings of the hard environment”, which became the first key point to stimulate the rapid growth of rural living environment upgrading research. Research hotspots included “artificial wetland”, “nitrogen and phosphorus removal”, “treatment mode,” and “willingness to pay”, etc. In 2018, the “Three-Year Action Plan for Rural Living Environment Upgrade” was implemented, which clarified the critical tasks of rural living environment upgrading and increased the number of articles issued. Research hotspots included “beautiful countryside”, “rural revitalization,” and “living environment”. On the whole, the research themes of rural habitat environment improvement can be summarized into four aspects, covering the study of the connotation and governance mode of rural habitat environment, the study of development status, the study of effect evaluation and influence factors, and the study of treatment mode and technology.

(2) Conclusion from the perspective of the four key tasks: The trend of the four priority tasks has a similar evolution, with more articles on rural living waste and fewer articles on rural toilet renovation and village appearance. The research themes of rural living waste treatment are mainly “artificial wetland”, “biofilm,” and other treatment technologies, which are mostly concentrated in the field of environmental science. The research topics of rural living waste include waste treatment technology, waste classification and treatment mode, and treatment willingness; the research topics of rural toilet renovation mainly focus on how to realize the harmless treatment of fecal matter and improve the satisfaction of rural residents’ toilet renovation. The research on village appearance is relatively scattered, and there are differences in the practical dilemmas and solution paths in different stages and different regions.

7.2. Implications

Given the above findings, this study finds that there are still fundamental problems of unbalanced regional development and insufficient development in critical areas in China’s rural living environment. Therefore, in order to improve the rural living environment comprehensively, it is necessary to strengthen the study of rural living environment improvement in western areas and areas where ethnic minorities live, adopt the survey and research method, and promote successful cases. In terms of wastes treatment, sewage treatment, and toilet reform, we should take into account the applicability of wastes treatment technology and sewage treatment mode; in the planning of villages, we should not demolish or build indiscriminately but conform to the reality of rural areas, meet the needs of farmers, and reflect the characteristics of villages.