1. Introduction
Urban expansion has been a worldwide phenomenon in the last few decades, especially in developing countries [
1,
2,
3]. Owing to the rapid urbanization and industrialization, the continuous growth in urban residents generates increasing demands for living and working space. This results in considerable farmland and ecological land being converted into urban land [
4,
5]. The biodiversity reduction [
6,
7], farmland reduction [
8], and urban heat island effect [
9,
10] caused by urban expansion seriously threaten the ecological security [
11]. The urban expansion also leads to social impacts, such as traffic congestion [
12], residential segregation [
5], and food shortages [
13].
To cope with these negative impacts in pace with urban expansion, many countries have adopted various measures, including planning tools, such as land use planning (LUP) [
14], green belt planning [
15], and urban growth boundaries [
16]; and political and fiscal tools, such as smart growth strategy [
17,
18] and regional tax resource sharing [
19,
20]. As one of the countries with the fastest urban expansion in the world, China has exploited quota-oriented LUP for more than 30 years to limit urban expansion, and the last planning is from 2006 to 2020. However, according to statistics, nearly two-thirds of the cities had exceeded the planning target of urban land for 2020 as early as 2016. Therefore, the question remains: is it effective? If it is effective, how effective is the quota-oriented planning tool for limiting urban expansion?
Planning implementation performance is an international burning issue that attracts considerable attention from either policymakers or researchers [
21,
22,
23]. Considerable research has evaluated the implementation of urban/land plans from two perspectives: a conformance and a performance perspective [
21,
24,
25]. For the conformance principle, scholars compare the actual land use with the planning goals to assess whether the planning goals are achieved and regard it as a criterion for judging the success or failure of the planning [
8,
26]. However, researchers who appreciate the performance principle argue that success is not an absolute concept and the plan is still effective if it is conducive to the improvement of subsequent decision making [
27,
28,
29]. Based on the performance principle, quantitative methods, such as econometric models, including the difference-in-difference model [
22,
30], and regression models [
23,
31,
32], have been used in recent years to evaluate the contribution of planning to the realization of planning targets.
Previous publications have made many meaningful explorations and laid a solid theoretical foundation for this study. Nevertheless, the following two aspects are rarely concerned. On the one hand, previous studies have paid much attention to explaining the external reasons for the failure of planning implementation [
33], but discussion on the rationality of the planning itself remains deficient. In China, the fairness of land quota allocation among cities in LUP is often questioned [
30]. Due to the top-down LUP system, the expected quota of specific land use types in local planning is allocated by superior planning, and the cities in the same jurisdiction share a total amount of land use quota. That is, cities in the same jurisdiction will have a competitive relationship in land use quota allocation. Hence, the rationality of land quota allocation among cities has become a vital factor affecting the success of planning and is worthy of discussion. On the other hand, whether spatial differences in the impact of LUP on urban expansion exist has been ignored by past research. Such differences may be caused by the strategic interactions between local governments, which has been found by previous research to occur during planning implementation. For instance, Wang et al. (2020) [
34] determined that the land supply decisions for a given local government will be affected by the land supply decisions of adjacent local governments. Therefore, in the context of China’s top-down LUP system and the coexistence of competition and cooperation between local governments, the reasons for the success or failure of LUP implementation should be explored in conjunction with administrative hierarchies and spatial relationships.
To fill these gaps, we quantify the pressure of LUP on urban expansion by constructing PCI, and conduct a case study of 280 Chinese cities using the GWR model to probe into the spatial effect of PCI on urban expansion. There are two major contributions of this paper. First, PCI is an indicator that combines the planning targets and the actual land use. It is more advantageous than indicators that only consider planning targets. The distribution analysis of PCI in space and urban hierarchy illustrates the equilibrium of urban land quotas in different cities, which will help to understand the governments’ preferences in quota allocation. Second, the GWR model applied in the case study can well recognize the spatial effect of PCI on urban expansion. This is very important for evaluating the performance of local governments in LUP implementation of different regions. This study attempts to give a reference for the scientific formulation of LUP and promote its effective implementation.
The rest of this paper is organized as follows.
Section 2 introduces the background of this study.
Section 3 describes the data and methods.
Section 4 presents the results and correlation analysis.
Section 5 discusses the key findings of this study.
Section 6 provides the conclusions.
2. Background
Urban expansion has played a crucial role in China’s economic development in the past 30 years. In China, the urban land is monopolized by the government, and urban expansion relies on land supply of the government [
30]. Through land supplying, on the one hand, the local governments could generate an amount of financial revenue, which supports the local economic development [
35,
36]. On the other hand, compared with the inner-city land, the low-cost expropriated land is conducive to the investment growth and the industrial development, which provides many development opportunities for the city [
34,
37]. Therefore, under the GDP-oriented performance achievement assessment, the local governments always tend to supply more land for urban expansion to stimulate local economic growth and achieve political promotion [
38]. According to the statistical yearbooks, the urban built-up area in mainland China has increased to 60,721.32 km
2 in 2020 (
Figure 1). This is 2.7 times that of in 2000 (21,379.56 km
2) and 4.7 times that of in 1990 (12,856 km
2) [
39]. Meanwhile, China’s urbanization rate is predicted to continue to grow at a speed of approximately 1% per year and reach 70% by 2030. By then, approximately 1 billion people will be living in cities [
40], and a massive demand for urban land will be generated in the future.
To deal with the disordered urban expansion, especially the large loss of farmland, China has implemented a strict farmland conservation system, with a quota-oriented LUP as the core measure [
31,
34]. ‘Quota’ is a mandatory indicator, which refers to the upper or lower limits for a given land type during the planning period (usually 15 years) within a jurisdiction. For urban land, upper quota limits are set as a restriction on urban expansion. As noted by Fang and Tian (2020) [
30], it is similar to the concept of urban growth boundaries and green belt planning, but they do not delineate the location of the future development.
As a key indicator elaborately designed in LUP, land use quota has not been well implemented. For the third round of LUP (2006–2020), the national urban land quota designed for 2020 was broken in 2013. By 2016, more than three-quarters of provincial-level planned urban land quotas had been breached. Meanwhile, nearly two-thirds of prefecture-level cities had run out of their urban land quota. Moreover, LUP has strict top-down enforcement regulations in the context of the unique five-level administrative system in China. The land use quota is first formulated in the National General Land Use Plan, which is the highest-level land use plan. Then, it is allocated to provinces, prefecture-level cities, counties, and townships step by step. Faced with such a situation, local governments complained about not only the shortage of construction land quota but also the fairness of quota allocation [
30]. However, this has not attracted sufficient attention from planners and policymakers. Therefore, in this study, we make an attempt to explore the equilibrium of urban land quota allocation and its spatial effect on the impact of urban expansion.
6. Conclusions
LUP has played an important role in controlling the rapid growth of urban land in China over the past decades. However, local governments often break the land use quota for economic development, leading researchers to doubt the effectiveness of LUP. Previous literature often focused on the overall implementation effect of LUP on controlling urban expansion but ignored its spatial differences. This study uses the GWR model to explore the spatial pattern of the implementation effect of LUP on controlling the speed of urban expansion.
The ULEI and ULES of 280 cities are calculated as the basic work. The results show that ULEI is randomly distributed in space, but ULES is characterized by spatial agglomeration. We conclude that the former may be sensitive to city size, while the latter is sensitive to city location.
The pressure that LUP has imposed on urban expansion is evaluated using PCI, which is calculated on the basis of the urban land quota allocated by the superior LUP. The spatial analysis of PCI suggests that some cities faced the pressure of insufficient urban land quota in 2009, and more cities faced this pressure in 2016. From the perspective of the entire country, the central and southwest regions with low levels of urbanization are facing relatively minimal pressure. This is beneficial to the economic and urbanization development of these regions but may also cause land waste. From a local perspective, economically developed cities are facing minimal pressure on urban land shortage. This finding indicates that the highly developed cities (especially provincial capitals) are prioritized when the total urban land quota of the entire province is allocated to the cities under its jurisdiction.
The spatial effect of LUP on ULES is estimated using the GWR model. LUP exerts significant negative effects on ULES for all of the 280 cities, and the effects show evident spatial differences among various regions. The impact of PCI on ULES is strong in areas with a relatively backward economy but high ULES, such as southwest China. On the contrary, it is relatively weak in areas with a relatively developed economy but low ULES, such as Eastern Coastal China.
This study is instructive for enhanced understanding of the impact of LUP on controlling urban expansion. The results imply that the coordinated development of cities among regions should be emphasized to determine a reasonable scale of urban land quota in LUP. In the future, the impact mechanism of LUP on urban expansion can be further explored by combining other spatial analysis models, such as geographical detector and multi-level regression. We will also explore the allocation principle of urban land quota on the basis of information entropy principles, Gini coefficient theory, or other methods. This study facilitates a scientific LUP and its effective implementation.