The reconstruction of historical land use intensification is the basis for in-depth exploration of climate change mechanisms and impacts. In this study, we first extracted the information of cropping intensity and crop combinations from gazetteers and journal publications for different regions of the North China Plain (NCP) since the Qing Dynasty. Then we reconstructed the spatiotemporal evolution of cropping pattern in the NCP for six periods, including the Qing Dynasty, the late Qing Dynasty to the Republic of China, the early period of the People's Republic of China (1960s, 1970s, and 1980s), and discussed the drivers of the change of cropping pattern. We found that: (1) From the Qing Dynasty to the early period of the People's Republic of China, the cropping intensity in the NCP was relatively stable, harvesting once a year or three times in two years. The situation of one harvest a year is mainly concentrated in the northern part of the study area, and the three harvests in two years are mostly distributed in Henan and Shandong provinces. Driven by irrigation and agricultural techniques, the cropping intensity in much of the NCP was two harvests a year, or a mix of two harvests a year and three harvests in two years during the 1960s and 1970s. In the 1980s, the cropping intensity was dominated by two harvests a year. (2) From the Qing Dynasty to the early period of the People's Republic of China, the crop combinations were relatively stable. The pattern of harvesting once a year is that cereals and sorghum are planted in the spring and harvested in the fall. The combination of crops harvested three times in two years is dominated by spring maize, winter wheat and beans. Since the 1960s, the composition of crops harvested twice a year has been winter wheat-summer maize in Shandong, Henan, and Hebei, and winter wheat-rice in the north of the Huaihe River. The summer crop of the crop mix harvested three times in two years developed from beans to maize/cereals. (3) Since the Qing Dynasty, the NCP has always had the thermal conditions for harvesting twice a year or three times in two years. The changes of thermal conditions are not the dominant factor driving the evolution of the cropping intensity in the NCP since the Qing Dynasty. Since the founding of the People's Republic of China, the improvement of agricultural production conditions and the reform of production relations have promoted the rapid development of multiple cropping.

The adaptive development of population-cultivated land-grain system is a key concern related to the people's livelihood and China's economy. Further, the proposed adaptive development serves as a major issue reflecting the sustainable development of regional food security. Accordingly, this study assesses the adaptability of China's population-cultivated land-grain composite system for the period ranging from 2004 to 2020 by employing the spatial variation function, GTWR model, and Markov chain to reveal the relevant spatiotemporal dynamic characteristics and influencing factors. The main findings are as follows: (1) The adaptability demonstrated an overall slow growth in fluctuation from 2004 to 2020; further, the adaptability level exhibited the characteristics of "main grain production area > grain main sales area > production and sales balance area" during 2004-2014; subsequent to 2014, the main sales area declined in consecutive years; thereby, falling to the third position. (2) Furthermore, there is a gradual uplift in the spatial difference in terms of adaptability, whereas the spatial correlation became the central factor influencing the spatial variation. Consistent with this, the extent of spatial variation in the northeast-southwest direction continued to strengthen, thus, displaying prominent migration characteristics. (3) In the context of dynamic evolution attributes, the system adaptation type exerts "path dependence" and "self-locking" influences, whereas the neighborhood background plays an imperative role in its dynamic change process. Alternatively, the higher the fitness level of the neighboring region, the stronger the probability of transferring to the higher level of the type area, and vice versa. (4) Furthermore, adaptability is reportedly influenced by capital status, planting structure, government support for agriculture, industrial structure, and international trade. Meanwhile, the aforementioned influences of each factor demonstrate significant spatiotemporal heterogeneity, among which, industrial structural adjustment significantly accelerates the development of the main food-producing regions in terms of the adaptability of the main production areas, the level of international trade to improve the main marketing areas mainly in the performance of the positive role, planting structural adjustment, and the positive force of fiscal support for agriculture augments over the time.

Severe diseases have a significant impact on patients and their families, and treating severe diseases is a basic need for people's well-being, so the issue of severe diseases is one of the key focuses in constructing a Healthy China. The occurrence and treatment of severe diseases in China show significant spatial heterogeneity. Therefore, taking geographical perspectives and methods can improve efforts to prevent severe diseases in different regions and facilitate the allocation of healthcare resources nationwide. This article collected individual samples from a national representative severe disease mutual aid platform, using prefecture-level cities as the basic analysis unit. Spatial correlation analysis, geographical detector model, multiple variables regression, geographic inequality decomposition, and cohort analysis. This article found that: (1) strong spatial clustering phenomenon exists in six severe diseases, including lung cancer, gastrointestinal cancer, breast cancer, cerebral stroke, acute myocardial infarction- and thyroid cancer; (2) several natural geographic and human geographic factors have strong explanatory power for the occurrence of severe diseases, but large variations exist in influencing factors among different diseases; (3) significant differences exist in healthcare resources among regions, leading patients to weigh both geographical distance and the quality of medical services when choosing a destination for cross-border medical treatment; (4) the disparity in the treatment-to-occurrence ratio of severe diseases across regions is large between regions divided by the Hu Huanyong Line; (5) the inequality level of the national treatment-to-occurrence ratio increased with the evolution of newer birth cohorts among patients and decreased with the establishment of new hospitals. This article concludes by suggesting policy policies tailored to local conditions to improve the prevention, control, and treatment of severe diseases.