Abstract:Soil is considered the key connection for material and energy transfer and transformation in the Earth's surface layer. Soil's components and ecological functions have been dramatically affected by rapid urbanization in recent decades. This is especially true for peri-urban ecosystems. A peri-urban ecosystem comprises the interaction and transition zones between urban and rural or natural ecosystems. Soils in peri-urban ecosystems are identified with both urban and rural/natural ecosystems' structural and functional features, and are prone to being affected by urbanization pressures. Soils in peri-urban ecosystems provide essential life-support functions and ecosystem services for urban and rural residents, including food supply, water purification, water conservation, contamination interception, leisure and entertainment services, cultural services, and more. Under rapid urbanization, a large area of agricultural and natural landscapes are converted to urban landscapes. Soils in peri-urban ecosystems therefore tend to be significantly disturbed because of increasing human activities, which change the soil processes and reduce the quality and diversity of soil functions such as food production, pollution attenuation, hydrological cycling, and energy balance. The inherent conflicts between urbanization and soil security have been studied for a long time. As urbanization levels in peri-urban ecosystems have increased, soil security problems in peri-urban ecosystems have been a key issue in recent studies. This study reviews published literature concerning soil security in peri-urban ecosystems and aims to contribute to scientific understanding of the interrelations between soil security and urbanization. Statistical analysis showed that the number of published papers concerning peri-urban ecosystems rapidly increased after 2000, especially in the past 5 years. Many studies concerning soil security were focused on urbanization's influence on soil processes in urban areas, including cropland loss, food production, climate change, and other processes linked with soils. However, only a limited number of studies that focused on peri-urban areas were found. The soil security problems in peri-urban ecosystem areas were often ignored by both rural and urban ecosystems research. In this review, the particularity and complexity of soil security in peri-urban ecosystems are discussed. In summary, we suggest that future peri-urban studies should focus on the following issues: (1) exploring comparative studies at a large scale under different urban sprawl modes, (2) exploring the tradeoff of ecosystem services in the framework of soil security in peri-urban ecosystems, and perspectives on current solutions for soil security in peri-urban ecosystems are proposed, (3) exploring the sources of contaminants in soil and their co-contamination in peri-urban ecosystems, and optimizing landscape patterns to promote soil security and ecosystem services, and (4) considering the sustainable development goals of peri-urban ecosystems and highlighting the multi-dimensional role of soil security in sustainable policy and management. Because soils in peri-urban ecosystems have their own unique set of socioeconomic and ecological features, soil security should be emphasized for understanding the environmental response to global urbanization.