The Correlation Effects and Mechanisms of Rural Restructuring and Transformation: A Case Study of the Jianghan Plain in China

: The rural decline accompanying industrialization and urbanization is a lingering puzzle in human society, while promoting rural restructuring and transformation is considered the primary task of contemporary rural development. It is the historical mission of rural geography research in the new era to scientiﬁcally understand the characteristics of contemporary rural development and accurately explain the patterns of rural reconstructing and transformation. In this paper, the Jianghan Plain in China is selected for the case study. Characteristic indexes are selected based on the “structure–function” correlation to interpret rural restructuring. Measurement benchmarks are uniﬁed through functional value marketization to interpret rural transformation. Multiple statistical analysis is adopted to identify the action paths and decipher the correlation mechanisms. The case study yields the following ﬁndings. (1) The rural restructuring on Jianghan Plain has spatial and temporal differences. Rural restructuring has roughly gone through the social restructuring-led, economic restructuring-led, and spatial restructuring-led evolution stages, showing spatially divergent patterns with high rural comprehensive restructuring index ( RRC ) areas concentrated around the main trafﬁc arteries and linear low RRC areas along the Yangtze River banks. (2) Rural restructuring and transformation on Jianghan Plain show signiﬁcant correlation effects. During the study period, the rural transformation magnitude ( RTM ) continues to increase and shows a spatial map similar to that of rural restructuring, with economic-spatial restructuring-led and economic-social restructuring-led as the main modes of rural transformation. (3) The correlation mechanism of rural restructuring and transformation on Jianghan Plain has characteristics typical of less-developed agricultural areas. The economic restructuring led by agricultural land changes and the social restructuring led by rural population outward migration remain the main paths of rural transformation, and the agricultural function still plays an important role in some rural areas. The quantitative measurement of rural region functions in this study need further optimization, and the reﬁnement and accuracy of regional function accounting needs further exploration. The research results are expected to provide a scientiﬁc basis for stimulating rural development and promoting sustainable rural development in contemporary developing countries


Introduction
Rural restructuring and transformation are the main features of contemporary rural development and the hotspots of rural geography research [1,2].Numerous studies have shown that rural restructuring and transformation are simultaneous and correlated with rural declines that accompany industrialization, urbanization, and globalization [3,4].However, the characteristics of rural reconstructing and the models of rural transformation in developed and developing countries are different.
Originating from the establishment of the global food system and the ensuing "farm economic crisis", the contemporary rural restructuring in developed countries has roughly gone through the "economic factors-led, cultural factors-led, and integrated factors-led" development stages [5].In the 1970s, the "farm economic crisis" in the Western world directly triggered the decline of productivism villages [6,7].In the meantime, post-industrialization and counter-urbanization promote the flow of industrial capital (low-end industries) and urban class (middle class) to rural areas, and the integration of industrial capital and urban class produces new consumption functions by restructuring the land-centered agricultural property relations, thus reviving the rural space [8].In the 1990s, postmodernism and "urban diseases" gave rise to the "rural pastoral dream" in urban societies.Through the reproduction of rural space and cultural construction, urban migrants with economic and cultural capital caused the identity otherness and social space marginalization of vulnerable rural groups, thus reshaping the rural cultural landscape and restructuring rural social relations [9,10].On the other hand, environmental changes and environmentally sustainable development have triggered a re-examination of rural space, and agricultural resource conservation, cultural landscape restoration, and sustainability of natural ecology have become the values of rural policies in Western developed countries [11,12].In the 21st century, along with the further development of globalization and the rapid progress of science and technology, the rural restructuring in the Western world has entered a new period characterized by "hybridity".Specifically, natural and nonhuman entities are as legitimately involved in rural restructuring as are social and human entities.The complex interactions between globality and locality, rurality and urbanity, and the mutual transformation of online virtual networks and offline social reality drive rural restructuring.The relationship between modernity and localism has shifted from binary opposition to mutual integration, and the vitality of traditional social culture has been rekindled, i.e., rural areas have achieved globalization because of localism [13,14].In contrast, the rural transformation in the Western world has gone through distinctive development stages of productive villages, consumption villages, multifunctional villages, and globalized villages [15,16].
The rural restructuring and transformation of developing countries, represented by China, originated in the process of rapid industrialization and urbanization, thus have connotations and characteristics different from those of developed Western countries [17,18].The initial inducements of rural restructuring in China are the large-scale population outflow caused by rapid industrialization and urbanization, and the transfer of production factors (such as land and capital) to urban nonagricultural industries.The main contents are economic, social, and spatial restructuring [19,20].Economic restructuring is mainly manifested in the marketization of agricultural production and changes in the rural industrial structure [21].Social restructuring is mainly manifested by social group differentiation and rural demographic changes [22].Spatial restructuring is mainly manifested by the parallel development of transportation networks, village abandonment, and environmental pollution, but the rural cultural style and landscape basis still exist [23].In terms of regional patterns, the rural restructuring characteristics are significant in developed regions such as the eastern coast but only preliminarily revealed in the inland farming regions such as the Huang-Huai-Hai Region [24,25].In terms of processes, rural areas are generally still in the evolving stage dominated by economic restructuring, and the rural restructuring processes are uneven across different regions and regional conditions [26].In terms of mechanisms, unlike the rural restructuring dominated by the "incremental" integration of urban factors in developed countries, the rural restructuring in contemporary China is dominated by the activation of "stock" rural factors [5].In terms of effects, rural restructuring in developed countries has contributed greatly to rural revival, while rural restructuring in contemporary China has, to a certain extent, triggered rural decline [27][28][29].
The current rural transformation in China also stems from the changes in rural population, industrial, and land-use structures, which is, in essence, the expansion of agricultural production space to multifunctional space.In terms of regional patterns, the transformation characteristics are significant in developed regions such as the eastern coast, but only preliminarily revealed in the inland farming regions such as the Huang-Huai-Hai Region [30,31].However, the mechanisms of rural transformation are different, with exoge-nous leading factors such as industrialization and urbanization, endogenous effects such as resource basis and location characteristics, and institutional innovation being the driving "troika", and rural gentrification has also become a major driver of suburban transformation in some megacities [32].The rural transformation has generally promoted the differentiated development of rural areas.Benefiting from their regional development basis and local development advantages, some areas have developed differently by actively integrating into urban civilization, while most areas have gone into decline because of deprivation and fragmentation.
In summary, as complex economic-social-spatial phenomena, the rural restructuring and transformation experience of developed countries is not universal, and geography may provide a unique disciplinary perspective.Therefore, it is necessary to analyze the rural restructuring characteristics and rural transformation modes in developing countries from the perspective of geography and based on the theory of man-land relationships.In fact, whether there is an intrinsic correlation between rural spatial restructuring and transformation remains a question.Deconstructing the mechanism of their correlation and the optimization strategy of rural transformation is what puzzles the current theoretical research.In view of this, the theoretical significance of this study is to suggest that rural reconstruction and transformation have certain correlation effects.Taking the rural development of Jianghan Plain in central China as an example, this study analyzes its rural restructuring characteristics, deciphers the rural transformation modes, and explains the intrinsic correlation mechanisms between the two.This study could enrich the theory of rural restructuring and transformation and promote the harmonious development of man-land relationships in agricultural areas.On the other hand, the rural restructuring and transformation in China have, to some extent, brought about rural declines.The question of restructuring rural resources, stimulating rural development, and promoting sustainable rural development through rural restructuring and transformation is an issue worthy of in-depth research by academics.Scientifically revealing the connection between rural restructuring and transformation is conducive to providing a theoretical foundation and practical basis for rural revitalization and integrated urban-rural development in countries around the world.Therefore, the practical significance of this study is to further clarify the general direction of future rural restructuring and transformation for developing countries, and to propose corresponding optimization paths to adapt to the changes in rural development factors and various challenges they bring.In this way, this study could help villages around the world thrive and maintain lasting social stability.

Literature Review
Rural restructuring, the core concept of rural geography, was proposed by the rural geography community in their exploration of rural changes in the European region [33,34], where the urbanization in the 1950s promoted European rural areas to undergo various changes in agricultural production methods, family structure modes, and land-use structures.In developing countries, such as China after the reform and opening up, many factors such as industrialization, urbanization, globalization, and informationization have intertwined to bring about rapid changes in rural man-land relationships and drastic changes in rural industrial forms, employment structures, and regional landscapes [35].Thus, rural restructuring is gradually becoming an important frontier topic in geography research [36].However, the academic community in China has different emphases and starting points in the perception of rural restructuring, and there are currently two mainstream views: the "result theory" and "policy theory" [37,38].The "result theory" considers rural restructuring as the factor recombination and relationship remodeling in rural regional systems, which is manifested as structural changes in the system [39,40].The "policy theory" believes that to adapt to the changes of rural internal factors and external impacts, different actors cooperate effectively to shape rural socio-economic patterns and region spatial structures through effective allocation and policy implementation, thus achieving factor adjustment, structural optimization, and functional enhancement of rural regional systems.In both theories, rural restructuring is a process of factor-structural-functional change in rural areas under the intertwined effect of exogenous drive and the endogenous response of rural regional systems.Only the "result theory" regards rural restructuring as a natural result of the evolution of rural regional systems and focuses on the formation mechanism of rural restructuring.The "policy theory" views rural restructuring as a policy instrument for the restructuring of rural regional systems and focuses on the practical approaches to rural restructuring.In fact, both the causal mechanisms and practical approaches of rural spatial restructuring are the key topics of rural geography research.
Rural transformation is a qualitative change and a transitional change in the function of the rural regional entities [41].Scholars have different opinions on the connotation and development measures of rural transformation.The Western world had early rural transformations and basically followed the evolutionary path from productivism to postproductivism.After World War II, countries such as the United Kingdom adopted the concept of agricultural productivism and pursued a strong policy of agricultural intervention.Financial subsidies, price guarantees, and agricultural protectionism were employed to support agricultural production, intensification, centralization, and specialization of agricultural production were emphasized, and the commercialization, industrialization, and commodification of agriculture were pursued to solve the postwar food shortage crisis [42].In the late 1970s, the large-scale and standardized agricultural production led to overproduction, and the misuse of pesticides and fertilizers seriously damaged the rural ecological environment.Thus, the agricultural function of Western villages gradually transitioned from productivism to post-productivism [43].The EU started to reduce financial support and price protection for agriculture and develop environmentally friendly and green agriculture [42].With the development of post-productivism, the diversification of agricultural transformation gradually extended beyond the agricultural sector, and the concept of post-productivism gradually expanded from explaining agricultural changes to the integrated changes of entire rural spaces [44].The focus of rural development began to shift to agriculture-related aspects, such as rural ecotourism, and nonagriculture development, such as services driven by rural industrial development and gentrification [45].After that, Wilson introduced the "multifunctional agricultural system" to express the diversity, nonlinearity, and heterogeneity of rural spaces, allowing for the multidimensional coexistence of productivist and post-productivist actions and ideas [46].Agricultural and rural studies are gradually moving toward the "multifunctional village" aspect [43].
As for developing countries, the research of rural transformation is still in the process of exploration, so there are different perceptions of it.Hamdouch [47] considered rural transformation as the transformation of rural socio-economic structures, institutional frameworks, and environmental resources.Cai [48] argued that rural transformation is mainly reflected in the comprehensive transformation of farmers' living and consumption levels, industrial-agricultural relations, urban-rural relations, and agricultural management modes.Liu [49] argued that rural transformation is the transition of traditional rural industries, production methods, and consumption structures, and the continuous transformation from an urban-rural dual structure to an urban-rural integrated development, with the goal of an all-round transformation of regional urban-rural and industrial-agricultural relations.Long [50] argued that rural transformation is the reconstruction of rural region spatial patterns and economic-social forms attributed to the factor reorganization and interaction during rural-urban population movements and economic-social development in the rapid industrialization and urbanization, and the response of local participants to these changes.Especially in recent years, guided by the goal of China's rural revitalization strategy, scholars have attempted to place rural transformation in the context of rural revitalization and then develop the idea of rural revitalization geography [51][52][53].
In summary, the relevant research worldwide has yielded abundant results.In particular, the Chinese geography community placed rural revitalization in the context of rural restructuring and transformation, and proposed to promote rural revitalization through spatial restructuring, land use, and urban-rural integration, showing the unique disci-plinary value of geography.However, there is still a tendency to confuse rural restructuring with rural transformation and rural transformation with rural change to varying degrees.Accordingly, this study intends to take Jianghan Plain, a key agricultural region in central China, as a case study and the man-land relationship as the theoretical foundation to analyze the rural restructuring characteristics and rural transformation modes while focusing on deciphering the intrinsic correlation mechanisms of rural restructuring and transformation.This study could provide targeted recommendations for rural development and rural revitalization in developing countries.

Research Design
From the perspective of geography, a rural regional system is a type of region with specific factor organization and functional correlation.Rural restructuring refers to the structural changes caused by the recombination of rural regional system elements and the reshaping of relationships, and rural transformation refers to the transforming change of the main function of the rural regional system [2].The structural changes in rural regional systems directly promote the evolution of rural region functions [54].Therefore, rural reconstructing is the process and rural transformation is the result.

Measurements of Rural Restructuring
Rural regional systems embody complex index relationships.According to the nature of contemporary rural man-land conflict and relevant research results, rural regional systems can be reconstructed and simplified into three dimensions: economic restructuring, social restructuring, and spatial restructuring.While economic restructuring and spatial restructuring characterize changes in human activities under internal and external environmental constraints, spatial restructuring refers to changes in the geographic environment (human geography and physical geography) under the action of human activities [54].Accordingly, the characteristic indexes were selected based on the "structure-function" correlation, and the restructuring characteristics were interpreted using an integrated factor system.According to the "factor-structure-function" relationship of rural regional systems, the choice of rural restructuring measurement indexes reflects the structural changes of the system and provides explanations for its functional transformation.The integrated factor system summarizes the overall characteristics of the system reconstruction and provides accurate information for the identification of dominant factors.Therefore, based on the previous results of our research group [55], RRC, RX, RY, and RZ were used to denote the comprehensive, economic, social, and spatial restructuring indexes of a certain rural area, respectively, with their numerical magnitudes reflecting the degree of drastic structural changes in the rural regional system.The measurement index system is shown in Table 1.Since the measuring unit of various indicators are not uniform, they should be standardized before being used to calculate the comprehensive indicators; that is, the absolute value of the indicators is converted into the relative value to solve the homogeneity of different quality index values.Moreover, different algorithms are adopted for data standardization of positive and negative indicators because of their different meanings.The specific methods are as follows [56]: Positive indicators: Negative indicators: where x ij is the value of the JTH index of the ith county unit.
After standardization of the original values of each index (positive and negative indexes), the weights were calculated using the entropy method.The essence of using the entropy method to estimate the weight of each index is to use the difference coefficient of the index information [57].The higher the difference coefficient is, the more important it is to the evaluation.
where w i is the wight of the JTH index and d j is the difference coefficient of the JTH index.Finally, the graded and comprehensive index values were obtained by summation.
where a i , b j , and c k are the weight coefficients calculated using the entropy method.Regional heterogeneity (Z 3 ) Urban and rural construction land area/total land area of the jurisdiction Note: the choice of relative indexes is intended to indicate the structural relationships and changes in the system.* the elite farmers are those who are between 30 and 55 years old, with certain education and business acumen, who belong to rural society.Population concentration and economic concentration are expressed as the proportion of the population and output of the jurisdictional center (the county town) to the total population and output of the jurisdiction, respectively.The outward accessibility is expressed as the accessibility of the jurisdictional center (the county town) to the regional center city, and the internal connectivity is expressed as the density of the jurisdictional grade road network.

Measurements of Rural Transformation
Rural regional systems embody composite functional structures.Based on our previous research results [55], the functions of rural regional systems were simplified into production function (economic output), living function (population carrying), and ecological function (ecological service), while the cultural function was integrated into the nonagricultural industrial production function and cultural service ecological function, respectively.Accordingly, the measurement benchmarks were unified through functional value marketization, and the transformation modes were summarized through functional structure heterogeneity.Let RCF, RPF, RLF, and REF be the comprehensive function, pro-duction function, living function, and ecological function indexes of a certain rural region respectively, then: where RPF = total rural economic output = rural agricultural economic output (RPF 1 ) + rural nonagricultural economic output (RPF 2 ); RLF = total income of rural residents = agricultural income of rural residents (RLF 1 ) + nonagricultural income of rural residents (RLF 2 ); REF = total rural ecological value = rural environmental protection value (REF 1 ) + other rural ecological value (REF 2 ); and REF was calculated using the method recommended by Xie [58] with the following modifications.
Let the population density of a certain rural region in the base period be P 0 (population of the center of the county divided by the total population of the county) and the economic density be E 0 (the total output of the central county divided by the total output of the county), and the population density of different years or different units be P and the economic density be E.The ecological function index calculated by the Xie method is REF 0 , and the modified ecological function index is REF.An ecological function adjustment factor is defined as r.r = where r stands for the relative intensity of the coupled effects of rural human production and living activities on the geographic environment.When r > 1, the impact of human activities on the geographical environment is greater than that in the base period, and the actual ecological function index is smaller than the theoretical calculations, i.e., REF = REF 0 /r.When r ≤ 1, the impact of human activities on the geographical environment is comparable to that in the base period, i.e., REF = REF 0 .
Since rural areas are agricultural-based regional spaces, the rural transformation is, in essence, the degradation or differentiated development of the agricultural function.Therefore, based on the previous findings of our research group [55], we introduced the rural transformation magnitude to judge the transformation of rural region functions.The rural transformation magnitude is defined as the proportion of rural nonagricultural functions in rural region functions, which is denoted as RTM.
where RBF is the rural agricultural function index, RPF 1 , RLF 1 , and REF 1 are the agricultural production function index, agricultural income function index, and rural environmental protection function index, respectively.When RTM > 50%, the agricultural functions fall to secondary positions, and the rural areas have been transformed.Otherwise, the agricultural functions are still dominant, and the rural areas have not yet been transformed.The structural change in rural regional systems triggers functional transformation, and the rural transformation modes can be summarized by correlating the rural transformation characteristics with the rural restructuring zoning.

Correlation Mechanisms between Rural Restructuring and Transformation
Rural restructuring and transformation are intrinsically and logically correlated.Developing countries are in the process of rapid industrialization and urbanization, and rural spaces are being marginalized.Under the market economy, exogenous drivers such as industrialization and urbanization provoke responsive changes in population, industry, and land within the rural regional system, and the system factor restructuring triggers the transformation of regional functions.Accordingly, multiple statistical analysis was adopted to identify the influencing factors, and the effect mechanisms were deciphered through correlation path analysis.After standardization of the relevant data, the rural nonagricultural function index (1−RBF) was used as the explained variable, and RX, RY, and RZ were used as the explanatory variables to clarify the main factors through which rural restructuring affects rural transformation.The possible paths through which rural restructuring affects rural transformation were analyzed by using (1−RBF) as the explained variable and the 10 indexes in Table 1 as the explanatory variables.

Case Selection and Data Description
Jianghan Plain in China was selected for the case study (Figure 1).Located in the middle reaches of the Yangtze River and the south-central part of Hubei Province, Jianghan Plain covers the entirety of Jingzhou and Jingmen, part of Yichang (Zhijiang and Danyang), part of Xiaogan (Yunmeng, Yingcheng, Anlu, and Hanchuan), and three cities directly managed by the province (Xiantao, Qianjiang, and Tianmen), totaling 20 areas.With a large rural population and a unique agricultural production status, the selected research area has the typical characteristics of China's main agricultural production areas and inland agricultural region villages.[61] from 2000 to 2020.Specifically, gross domestic product (GDP) and the values added of primary, secondary, and tertiary industries were converted into comparable prices with 2000 as the base period.Missing GDP data for individual years were completed using linear interpolation.The spatial data, such as administrative boundaries and rivers of the relevant counties and cities, were from the National Science and Technology Infrastructure Platform Construction Project, the "National Earth System Science Data Center, Lake-Basin Science Data Center (www.geodata.cn,accessed on 11 October 2021)".

Empirical Analysis 4.1. Analysis of Rural Restructuring System on Jianghan Plain (1) Analysis based on time variation
Based on the temporal dimension, the rural restructuring characteristics on Jianghan Plain were analyzed, and the rural comprehensive restructuring index (RRC), rural economic restructuring index (RX), rural social restructuring index (RY), and rural spatial restructuring index (RZ) of Jianghan Plain were calculated (Figure 2).

Analysis of Rural Restructuring System on Jianghan Plain
(1) Analysis based on time variation Based on the temporal dimension, the rural restructuring characteristics on Jianghan Plain were analyzed, and the rural comprehensive restructuring index (RRC), rural economic restructuring index (RX), rural social restructuring index (RY), and rural spatial restructuring index (RZ) of Jianghan Plain were calculated (Figure 2).Judging from the calculated values, RX, RY, and RZ of rural areas on Jianghan Plain increase continuously, and the sum of all three drives RRC to increase continuously.During the study period, RX increased from 0.04 to 0.30, RY increased from 0.05 to 0.25, and RZ increased from 0.01 to 0.33, causing RRC to increase from 0.10 to 0.88.Therefore, the economic, social, and spatial structures of the rural areas on Jianghan Plain were constantly changing, which promoted structural changes in the rural regional system.In terms of the rate of change, RX increased 6.50 times, RY increased 4.00 times, RZ increased 32.00 times, and RRC increased 7.80 times during the same period.Therefore, the economic, social, and spatial restructuring of rural areas on Jianghan Plain were unbalanced, and spatial restructuring was more critical to the evolution of the rural regional system.In terms of contribution rate, the average contribution rate of RX to RRC during the study period was 40.38%, and the contribution rates of RY and RZ were 33.00% and 26.62%, respectively.Therefore, economic restructuring had a more fundamental role in the evolution of rural regional systems on Jianghan Plain.However, with 2009 as the cut-off year, the contribution rates of RX, RY, and RZ to RRC showed different variation characteristics.The contribution rate of RX rose in the early stage and fell in the later stage.The contribution rate of RY declined significantly in the early stage and stabilized in the later stage.The contribution rate of RZ fluctuated in the early stage and increased steadily in the later stage.Thus, the different dimensions of rural restructuring on Jianghan Plain played different roles at different stages.
(2) Analysis based on spatial variation The rural restructuring characteristics on Jianghan Plain were analyzed based on the Judging from the calculated values, RX, RY, and RZ of rural areas on Jianghan Plain increase continuously, and the sum of all three drives RRC to increase continuously.During the study period, RX increased from 0.04 to 0.30, RY increased from 0.05 to 0.25, and RZ increased from 0.01 to 0.33, causing RRC to increase from 0.10 to 0.88.Therefore, the economic, social, and spatial structures of the rural areas on Jianghan Plain were constantly changing, which promoted structural changes in the rural regional system.In terms of the rate of change, RX increased 6.50 times, RY increased 4.00 times, RZ increased 32.00 times, and RRC increased 7.80 times during the same period.Therefore, the economic, social, and spatial restructuring of rural areas on Jianghan Plain were unbalanced, and spatial restructuring was more critical to the evolution of the rural regional system.In terms of contribution rate, the average contribution rate of RX to RRC during the study period was 40.38%, and the contribution rates of RY and RZ were 33.00% and 26.62%, respectively.Therefore, economic restructuring had a more fundamental role in the evolution of rural regional systems on Jianghan Plain.However, with 2009 as the cut-off year, the contribution rates of RX, RY, and RZ to RRC showed different variation characteristics.The contribution rate of RX rose in the early stage and fell in the later stage.The contribution rate of RY declined significantly in the early stage and stabilized in the later stage.The contribution rate of RZ fluctuated in the early stage and increased steadily in the later stage.Thus, In general, the rural restructuring of Jianghan Plain is characterized by typical spatial heterogeneity.In terms of location characteristics, rapidly urbanizing areas are advantageous for rural restructuring, while traditional agricultural areas are disadvantageous for rural restructuring.During the study period, Jingmen and Jingzhou municipal districts were always at the high RRC end, and traditional agricultural areas such as Jiangling and Jianli counties were always at the low RRC end.In terms of regional patterns, the layout and spatial structure of important traffic arteries in the region basically outline the spatial contour of rural restructuring.In 2000, the traffic arteries on Jianghan Plain mainly included the Jiaozuo-Liuzhou Railway (north-south) in the west, the Wuhan-Yichang Railway (eastwest) in the center, and the Wuhan-Danjiangkou Railway (north-south) in the east, and the high RRC areas were mainly along the above traffic arteries in a "U" shaped structure.After the completion and operation of the east-west Changjiangbu-Jingmen Railway in the north (2011), the high RRC areas formed a distribution pattern tightly around the four main traffic arteries above as of 2020.Thus, external environmental factors such as industrialization and urbanization had an extremely important impact on the rural restructuring on Jianghan Plain.Specifically, the rural restructuring on Jianghan Plain was characterized by significant structural imbalance.Due to the fundamental and critical role of rural economic and spatial restructuring, RX and RZ showed roughly the same spatial dynamics and variation trends as RRC.However, rural social restructuring was characterized by randomness and homogeneity, as shown by the relatively fragmented spatial distribution and relatively small locational differences of RY.As a traditional agricultural region in central China, rural population outflow is the main driver of rural spatial restructuring on Jianghan Plain, resulting in the discrete nature of rural social restructuring contrasting the aggregation of rural economic and spatial restructuring.
(3) Rural restructuring zoning of Jianghan Plain Drawing on relevant research results [62], the rural restructuring type zoning on Jianghan Plain was achieved based on the SOFM model and the combination of RX, RY, and RZ with ∆RX, ∆RY, and ∆RZ (Figure 4).As shown in Figure 4, the rural restructuring on Jianghan Plain can be divided into two zones.The zone covered in green (Zone I) includes 14 areas, such as Jingzhou, with a circular distribution along the Jiaozuo-Liuzhou Railway-Wuhan-Yichang Railway-Wuhan-Danjiangkou Railway-Changjiangbu-Jingmen Railway line.With high-intensity rural restructuring, Zone I had a multi-year average RRC of 0.60, higher than the multi-year average of Jianghan Plain.The zone covered in orange (Zone II) includes 6 areas, such as Jiangling, with geographical locations along the Yangtze River.With low-intensity rural restructuring, Zone II had a multi-year average RRC of 0.48, lower than the multi-year average of Jianghan Plain.By dimension, the contribution rates of RX, RY, and RZ to RRC are 44.94%,35.54%, and 19.52% in Zone I, respectively; the contribution rates of RX, RY, and RZ are 44.99%,40.06%, and 14.95% in Zone II, respectively.Economic restructuring played a major role in the rural restructuring of the two zones.However, the contribution rate of RZ in Zone I is significantly higher than that in Zone II, indicating the relative importance of spatial restructuring for Zone I.The contribution rate of RY in Zone II is significantly higher than that in Zone I, verifying the relative importance of social restructuring for Zone II.As shown in Figure 4, the rural restructuring on Jianghan Plain can be divided into two zones.The zone covered in green (Zone I) includes 14 areas, such as Jingzhou, with a circular distribution along the Jiaozuo-Liuzhou Railway-Wuhan-Yichang Railway-Wuhan-Danjiangkou Railway-Changjiangbu-Jingmen Railway line.With high-intensity rural restructuring, Zone I had a multi-year average RRC of 0.60, higher than the multi-year average of Jianghan Plain.The zone covered in orange (Zone II) includes 6 areas, such as Jiangling, with geographical locations along the Yangtze River.With low-intensity rural restructuring, Zone II had a multi-year average RRC of 0.48, lower than the multi-year average of Jianghan Plain.By dimension, the contribution rates of RX, RY, and RZ to RRC are 44.94%,35.54%, and 19.52% in Zone I, respectively; the contribution rates of RX, RY, and RZ are 44.99%,40.06%, and 14.95% in Zone II, respectively.Economic restructuring played a major role in the rural restructuring of the two zones.However, the contribution rate of RZ in Zone I is significantly higher than that in Zone II, indicating the relative importance of spatial restructuring for Zone I.The contribution rate of RY in Zone II is significantly higher than that in Zone I, verifying the relative importance of social restructuring for Zone II.ral restructuring, Zone I had a multi-year average RRC of 0.60, higher than the multi-year average of Jianghan Plain.The zone covered in orange (Zone II) includes 6 areas, such as Jiangling, with geographical locations along the Yangtze River.With low-intensity rural restructuring, Zone II had a multi-year average RRC of 0.48, lower than the multi-year average of Jianghan Plain.By dimension, the contribution rates of RX, RY, and RZ to RRC are 44.94%,35.54%, and 19.52% in Zone I, respectively; the contribution rates of RX, RY, and RZ are 44.99%,40.06%, and 14.95% in Zone II, respectively.Economic restructuring played a major role in the rural restructuring of the two zones.However, the contribution rate of RZ in Zone I is significantly higher than that in Zone II, indicating the relative importance of spatial restructuring for Zone I.The contribution rate of RY in Zone II is significantly higher than that in Zone I, verifying the relative importance of social restructuring for Zone II.From a chronological point of view, the rural transformation of Jianghan Plain has certain progressivity.The RTM of the areas on Jianghan Plain increased continuously during the study period, and the regional average RTM increased from 52.46% in 2000 to 82.45% in 2020, with an average increase of 57.17 percentage points.Specifically, the RTM of Jiangling along the Yangtze River showed the smallest increase from 42.45% to 62.25%, an increase of only 23.80 percentage points, while the increase of Jingshan in the north of Jianghan Plain was the largest from 37.57% to 78.78%, an increase of 41.21 percentage points.Thus, the rural transformation has been a common phenomenon in the rural areas of Jianghan Plain, in which the traffic arteries played an important role.Spatially, the rural transformation of Jianghan Plain had heterogeneous characteristics.The rural transformation areas on Jianghan Plain were not synchronized during the study period.The transformed areas with RTM > 50% were mainly distributed in a "U" shape along the main traffic arteries in the region in 2000.Excitingly, all areas underwent transformations in 2020, but the areas with high levels of transformation (RTM > 75%) have encircled the four major traffic arteries.A comparison with Figure 3 suggests that rural transformation on Jianghan Plain had a spatio-temporal pattern that was roughly in correspondence with rural restructuring, indicating that rural restructuring and transformation were intrinsically and logically correlated.Surprisingly, Songzi and Gong'an are located in low RRC areas with low-intensity rural restructuring, but high RTM areas (>75%) with high levels of transformation.The main reason is that the proportion of elite farmers (Y 2 ) and spatial concentration (Z 1 ) in Gong'an are low, and its agricultural production function index (RPF 1 ) is also low.Meanwhile, the agricultural output proportion (X 1 ) in Songzi city is relatively low.Likewise, the rural environmental protection function index (REF 1 ) is low.

Analysis of Rural Transformation Correlation on Jianghan Plain
(2) Regional Types of Rural Transformation on Jianghan Plain Based on Figure 4, the RCF, RBF, RTM, rural agricultural production function index (RPF 1) , rural agricultural income function index (RLF 1 ), and rural environmental protection function index (REF 1 ) of Jianghan Plain were calculated for each zone (Table 2).Note: The current values are the 2020 functional index, and the variations are the 2020 functional index minus the 2000 functional index.
According to Table 2, the regional differentiation of rural transformation on Jianghan Plain is significant and corresponds well with rural restructuring.First, rural restructuring positively affects rural transformation.Zone I has undergone high-intensity rural restructuring, with a multi-year average RRC 23.56% higher than that of Zone II.In contrast, Zone I has also undergone high-level rural transformations, with an RCF of 3.34 in 2020, 49.77% higher than that of Zone II.From 2000 to 2020, RCF increased by 2.52, 58.49% higher than that of Zone II.Second, spatial restructuring favors the expansion of nonagricultural functions, while social restructuring tends to stabilize agricultural functions.Zone I had prominent spatial restructuring characteristics, and the contribution of RZ was 5.0 percentage points higher than that of Zone II.Zone II had significant social restructuring features, and the contribution of RY was 4.5 percentage points higher than that of Zone I.In contrast, in 2020, the RCF in Zone I was significantly higher than that in Zone II, but the RBF was lower than that in Zone II.From 2000 to 2020, the RBF in Zone I increased by 0.15, lower than the increase of 0.21 in Zone II.Third, the structural differences in rural restructuring cause structural changes in agricultural functions.From 2000 to 2020, the REF 1 in Zone I declined faster than that in Zone II, while the RLF 1 in Zone II increased faster than that in Zone I.The expansion of nonagricultural functions exacerbated the pressure on the rural ecological environment, while the stability of agricultural functions ensured the basic income of rural residents.Accordingly, the rural transformation in Zone I can be regarded as economic-spatial restructuring-led, and that in Zone II can be regarded as economic-social restructuring-led.In fact, the two transformation modes may imply different stages of rural transformation. (

3) Correlation Mechanism of Rural Transformation on Jianghan Plain
The essence of rural transformation is the alternation of nonagricultural functions in rural areas.(1−RBF) was used as the explained variable, and RX, RY, and RZ were used as explanatory variables to determine the influence degrees of different factors.Using (1−RBF) as the explained variable and the 10 indexes in Table 1 as the explanatory variables, the influence mechanisms of different factors were revealed.Statistical analysis showed the following findings.The correlation coefficients among the explanatory variables were below 0.7.After adjustment, R 2 was 0.319 and 0.335, respectively, and DW was 1.597 and 1.826, respectively.The standardized residual plots of the variables were tested to be consistent with a normal distribution.Thus, the model setup was reasonable.Stepwise regression analysis was performed using the SPSS 24.0 software (Table 3).   1. Spatial restructuring significantly affected the expansion of nonagricultural functions (standardized correlation coefficient of 0.629), consistent with the analysis findings above.(2) Economic, social, and spatial restructuring affected the changes in rural nonagricultural functions through different paths.RX negatively affected the changes in nonagricultural functions mainly through the changes in the proportion of agricultural arable land (X 2 ).A smaller X 2 means an increase in the supply of nonagricultural land, which is conducive to the expansion of nonagricultural functions.RY negatively affected nonagricultural function changes, mainly through changes in the proportion of the rural population (Y 1 ).A smaller Y 1 means a larger nonagricultural transfer of the rural population, which provides labor and market support for the expansion of nonagricultural functions.RZ positively affected nonagricultural function changes mainly through spatial concentration (Z 1 ) and regional heterogeneity (Z 3 ).A greater Z 1 means higher levels of population and economic aggregation, which is conducive to the expansion of nonagricultural functions.A greater Z 3 means higher levels of urban and rural construction, which is conducive to the expansion of nonagricultural functions.

Discussion
With the man-land relationship as the theoretical foundation and Jianghan Plain, a traditional agricultural region in central China, as the case study area, this study analyzed rural restructuring and transformation through the structural and functional changes in the rural regional system and attempted to decipher the intrinsic correlation between the two.The results of this study are expected to provide theoretical insights for the geographical study of rural restructuring/transformation and information support for rural revitalization in the case study area.
(1) The rural areas of Jianghan Plain are undergoing a progressive restructuring process.
In general, the comprehensive rural restructuring index (RRC) and the indexes of each dimension (RX/RY/RZ) on Jianghan Plain maintained different degrees of increase during the study period.Specifically, rural restructuring has roughly gone through the social restructuring-led, economic restructuring-led, and spatial restructuringled evolution stages, showing spatially divergent patterns with circular high RRC areas around the main traffic arteries and linear low RRC areas along the bank of the Yangtze River.
(2) The level of rural regional transformation basically corresponds to the intensity of rural restructuring on Jianghan Plain.From a chronological point of view, 10 zones on Jianghan Plain still had rural transformation magnitudes (RTM) below 50% in 2000, but all counties and cities had RTM > 50% in 2020, indicating stable rural transfor-mation.Spatially, RTM presented a spatial map similar to that of rural restructuring.
According to the characteristics of the correlation between rural restructuring and transformation, Jianghan Plain had economic-spatial restructuring-led and economicsocial restructuring-led rural transformation modes.(3) Rural restructuring and transformation on Jianghan Plain had certain correlation paths between them.Rural restructuring and transformation on Jianghan Plain had a positive correlation, and economic, social, and spatial restructuring (X, Y, and Z) all impacted rural nonagricultural functions.X and Y negatively affected nonagricultural changes through the proportion of agricultural arable land (X 2 ) and the proportion of the rural population (Y 1 ), respectively, while Z positively affected nonagricultural function changes mainly through spatial concentration (Z 1 ) and regional heterogeneity (Z 3 ).

Conclusions
Rural restructuring and transformation are the main characteristics of contemporary rural development and the current background of rural revitalization worldwide.An accurate understanding and grasp of the scientific connotation of rural restructuring and transformation and their logical correlation are conducive to deepening the theoretical study of rural geography and can provide theoretical guidance and a decision-making basis for rural revitalization worldwide.
(1) Rural restructuring and transformation are intrinsically and logically correlated.Rural restructuring is the structural changes caused by factor reorganization in rural regional systems, while rural transformation is the functional changes caused by the structural remodeling in rural regional systems.The rural region function changes are the reflection of the man-land relationship and a fundamental tool for academics to describe rural transformation.Interpreting rural transformation and correlating it with rural restructuring based on rural region function changes is an effective way to bring rural development research back to geographical traditions.(2) The correlation paths between rural restructuring and transformation had spatial and temporal differences.Jianghan Plain is an underdeveloped agricultural region in central China.The economic restructuring led by agricultural land changes and the social restructuring led by rural population outward migration remained the main mechanisms of rural transformation.In contrast, the economic restructuring led by agricultural input changes and the social restructuring led by changes in elite farmers were more decisive for the rural transformation of some developed coastal regions.Thus, the differences in the characteristics and levels of rural transformation in the two types of regions can be explained.(3) Restructuring rural resources, stimulating rural development, and promoting sustainable rural development are real issues that developing countries must address in the context of rapid urbanization.According to the above findings, this study proposes countermeasures to promote future rural transformation in the following aspects.(1) The rural population development transformation must be accelerated.New agricultural business entities should be cultivated, and a national system of professional farmers must be established.By encouraging high-level talents to return to their hometowns for employment and entrepreneurship through active policies, the governments can focus on training a group of new professional farmers and a group of rural management cadres who "know agriculture and love rural areas" to provide a talent guarantee for rural transformation.(2) The rural ecology-industry integrated development must be promoted.New rural industries and businesses should be vigorously developed, and the deep integration of agriculture and other related industries, such as tourism, must be promoted, thus enhancing the upgrading of the rural industrial structure.(3) Rural transportation infrastructure construction must be improved to provide long-term support for the development of new modern rural industries.(4) The rural land system reform must be promoted.The overall rural land-use plan should be continuously improved; idle land resources in rural areas should be integrated; the land-use structure in rural areas should be optimized; the rural region functions in China should be continuously enhanced; and the rural land-use transformation should be promoted.(4) The study of rural restructuring and transformation needs further attention.Unifying the measurement benchmark through functional value marketization can provide a scientific basis for the intraregional and interregional comparison of comprehensive functions and specific functions.However, the refinement and improved accuracy of regional function accounting merit further exploration.Considering the actual rural development in each country, the effects of government policies cannot be ignored, and the influence of globalization is increasing.The impact of these factors on the rural restructuring and transformation in different regions is still to be explored in depth.On the other hand, the ecological impact of rural restructuring and transformation cannot be ignored.Although some studies have focused on the ecological and environmental effects of rural land use, there are significant limitations in terms of research indexes, research methods, and research perspectives.Strengthening the quantitative research on the mechanisms and effects of rural restructuring and transformation is also a major trend in future research.

Sustainability 2023 , 19 Figure 1 .
Figure 1.Regional map of Jianghan Plain.The study period was from 2000 to 2020.The economic and social data required for the study were mainly from the China City Statistical Yearbooks [59], China County Statistical Yearbooks [60], and Hubei Statistical Yearbooks [61] from 2000 to 2020.Specifically, gross domestic product (GDP) and the values added of primary, secondary, and tertiary industries were converted into comparable prices with 2000 as the base period.Missing GDP data for individual years were completed using linear interpolation.The

Figure 1 .
Figure 1.Regional map of Jianghan Plain.The study period was from 2000 to 2020.The economic and social data required for the study were mainly from the China City Statistical Yearbooks [59], China County

Figure 3 .
Figure 3. Spatial pattern and changes of rural restructuring on Jianghan Plain from 2000 to 2020.

( 1 )
Spatial and Temporal Characteristics of Rural Transformation on Jianghan PlainBased on the county, city, and district units, we calculated the rural comprehensive function index (RCF), rural agricultural function index (RBF), and rural transformation magnitude (RTM) of Jianghan Plain in 2000 (the initial stage) and 2020 (the final stage) (Figure5).

( 1 )
Spatial and Temporal Characteristics of Rural Transformation on Jianghan PlainBased on the county, city, and district units, we calculated the rural comprehensive function index (RCF), rural agricultural function index (RBF), and rural transformation magnitude (RTM) of Jianghan Plain in 2000 (the initial stage) and 2020 (the final stage) (Figure5).

Figure 5 .
Figure 5. Spatial differentiation of rural transformation on Jianghan Plain in 2000 and 2020.Light green indicates not transformed, and green indicates transformed.

Table 1 .
Index system and interpretation of rural restructuring.

Table 2 .
The rural region function structure and its changes on Jianghan Plain.

Table 3 .
Double regression analysis of rural agricultural functional changes on Jianghan Plain.: ** and *** represent significance at the 0.05 and 0.01 levels, respectively.B is the unstandardized coefficient. Notes

Table 3
suggests the following findings.(1) Economic, social, and spatial restructuring all impacted rural nonagricultural function changes, where (1−RBF) was negatively correlated with RX and RY and positively correlated with RZ, consistent with the rural restructuring properties in Table