Many scholars have conducted in-depth research on the theme of land use change and food security, and formed fruitful research results, but there is a lack of quantitative analysis and comprehensive evaluation of research achievements. Therefore, based on the relevant literature on the theme of land use change and food security in the core collection of the Web of Science (WOS) database, this paper takes the advantage of CiteSpace and VOSviewer bibliometric software to draw the cooperative network and keyword cooccurrence map to analyze the research progress and frontier. The results reveal that: (1) The research started in 1999 and can be divided into three stages: initial research, rapid development, and a stable in-depth stage. This topic has increasingly become a research hotspot in the academic community. (2) The distribution of research institutions is concentrated and forms a small cluster, and the research networks between developed and developing countries have been established, and developed countries are in the core position, but the cooperation network is not prominent. (3) The research content is becoming increasingly organized and systematic, and the research hot topics are divided into seven aspects. (4) The research area of the subject covers multiple levels, such as global, national, and specific natural geographical regions, and has formed a research system of geographic information technology and satellite remote sensing technology. It also presents the trend of cross integration with economics, land management and soil science. In the future, theoretical innovation still needs to be strengthened, and we should strengthen the research on the impact of agricultural chemical fertilizers on food security and study the impact of urban expansion on land use change.

Coastal farmers earn their living by the sea, and their willingness to pay (WTP) is particularly important for coastal zone ecological protection (CZEP). What are the specific impacts of livelihood capital and distance effect on farmers' WTP for CZEP? And what are the impact paths of these effects? To answer these questions, taking the coastal zone of the Beibu Gulf of China as an example, this paper constructs an index system based on sustainable livelihood theory, carries out research and design combined with the contingent valuation method (CVM), and conducts an empirical study on the relationship between livelihood capital, distance effect and WTP for ecological protection with the help of the entropy method, ordinary least squares (OLS) linear regression model and bootstrap method. The results show that (1) only 56.23% of the respondents have a WTP for CZEP, while 43.77% of the respondents refuse to pay. (2) The scores of each dimension of farmers' livelihood capital are as follows: risk perception (0.635) > natural capital (0.531) > financial capital (0.406) > human capital (0.299) > social capital (0.130) > physical capital (0.110), and farmers' livelihood capital and distance effect have an inverted U-shaped relationship with the WTP for ecological protection. (3) The ecological protection payments of pure farmers, type 1 farmers, type 2 farmers and nonfarmers were 151.83, 112.73, 78.87 and 95.58 RMB/year, respectively, and the influencing factors are heterogeneous. (4) We found that the mediating effects of natural capital, physical capital and financial capital are negative, social capital and risk perception are positive, while the mediating effects of human capital are not significant. Therefore, the government should establish a comprehensive management system that is cross-regional, cross-departmental, coordinated, systematic and efficient across the coastal zone.

The growth of rural residential land (RRL) areas has led to the encroachment of cultivated land, which has seriously reduced cultivated land use efficiency (CLUE). This paper takes 42 cities in the middle reaches of the Yangtze River (MRYR) as an example, using the kernel density estimation method, the Super-SBM model, and mediating effect test methods to explore the impact of RRL change on CLUE during 2000–2020. Specifically, based on the analysis of the spatiotemporal distribution characteristics of RRL and CLUE, this paper attempts to further explore the influence path of RRL change on CLUE and test whether there is a mediating effect. The results show that (1) the overall RRL area increased by 30,386.34 hm², except for the decrease in RRL area in a few regions of Hunan Province, and the RRL area in other regions increased. (2) The hot-spot and sub-hot-spot regions of CLUE in the MRYR were mainly concentrated in northwestern Hubei Province and eastern Hunan Province, and the hot-spot and sub-hot-spot regions in Hunan Province are the highest among the three provinces. (3) Under the control of socioeconomic variables, the change in RRL has a significant negative impact on CLUE. (4) The area of cultivated land occupied by rural residential land (CLRRL) has a mediating role during 2000–2020, while the per capita cultivated land area (PCLA) and the rural permanent population (RPP) only have a mediating role during 2000–2010. In the future, the government should strictly prohibit the occupation of cultivated land by RRL and to improve the CLUE.