School of Geography and Tourism, Shaanxi Normal University, Xi'an 710119, China.
State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
Sci Total Environ. 2023 May 1;871:162053. doi: 10.1016/j.scitotenv.2023.162053. Epub 2023 Feb 8.
The expansion of construction land due to urbanization is the most rapid land use change in contemporary human history and has always occupied high-quality cropland, posing a severe threat to cropland and food security, it's essential to clarify the impact of urbanization on cropland and food security. This study proposed a research framework based on the regulating role of human activities, used quantifiable complex network analysis to uncover the vital role of urbanization in the evolution of land systems, and combined trajectory analysis of crop yield change to explore the impact of different urbanization modes (urban, town, and township mode) on food security through a continuous observation on 4259 township-level administrative regions of the Loess Plateau from 1990 to 2020. The findings proved that urbanization occupied the greatest land use area of cropland, and the town mode occupied 58.62 % of all urbanization modes encroaching on cropland, which has become a new pattern for advancing the urbanization development in the Loess Plateau. Construction land is more likely to be transferred in than out in the land use transfer network, while other land use types converted to construction land will be difficult to reverse. The Chinese government has implemented pragmatic policies, improved agricultural production techniques, and promoted agricultural intensification, resulting in a considerable increase in crop productivity and crop yield and the achievement of basic crop yield self-sufficiency of the Loess Plateau, so urbanization would not endanger food security. This study not only provides a more systematic research framework for related studies but also provides a theoretical basis for securing food security in other rapidly urbanizing regions of the world.
城市化导致建设用地扩张是当代人类历史上土地利用变化最快的过程，它一直占用着高质量的耕地，对耕地和粮食安全构成了严重威胁，因此，阐明城市化对耕地和粮食安全的影响至关重要。本研究提出了一个基于人类活动调节作用的研究框架，利用可量化的复杂网络分析揭示了城市化在土地系统演变中的关键作用，并结合作物产量变化轨迹分析，通过对黄土高原 4259 个乡镇级行政区域从 1990 年到 2020 年的连续观测，探讨了不同城市化模式（城市、镇、乡模式）对粮食安全的影响。研究结果证明，城市化占用了最大的耕地面积，其中镇模式占用了所有城市化模式侵占耕地的 58.62%，已成为推进黄土高原城市化发展的新模式。在土地利用转移网络中，建设用地更倾向于转入而不是转出，而其他土地利用类型转化为建设用地则难以逆转。中国政府实施了务实的政策，提高了农业生产技术，促进了农业集约化，使得作物生产力和作物产量大幅提高，实现了黄土高原的基本作物产量自给自足，因此城市化不会危及粮食安全。本研究不仅为相关研究提供了更系统的研究框架，也为世界其他快速城市化地区保障粮食安全提供了理论依据。
