The pattern of grain self-sufficiency plays a fundamental role in maintaining food security. We analyzed the patterns and determinants of grain production and demand, as well as grain self-sufficiency, in China over a 30-year period. The results show that China’s total grain production, with an obvious northeast–southwest direction, increased by 63%, and yields of rice, wheat, corn, tubers, and beans increased by 16, 49, 224, 6, and 103%, respectively. The trends in ration and feed grain consumption changes at the provincial scale were roughly the same as at the national scale, with the ration consumption ratio decreasing and the ratio of feed grain consumption increasing. The ration consumption in Northwest China was relatively high, while the feed grain consumption rates in Shanghai, Guangdong, Beijing, Tianjin, and Chongqing were higher. Compared with ration and feed grain, the proportions of seed grain and grain loss were relatively small. China’s grain consumption mainly concentrated in the central and eastern regions of China. Total grain, rice, corn, wheat, tubers, and beans consumption in feed grain showed a northeast–southwest trend, with consumption centers all shifting southward in the 30-year period. Corn accounted for the largest proportion in feed grain, followed by beans. Urban feed grain and urban ration hot spot areas have gradually transferred from the northwest to southeast coastal areas. The hot spots of rural feed grain consumption and rural ration consumption remained almost unchanged, located in the south of the Yangtze River and Central and Southern China, respectively. The grain self-sufficiency level developed well in the study period, while the areas with grain deficit were Beijing, Tianjin, Shanghai, Zhejiang, Fujian, Guangdong, and Hainan. The areas with high supply and high demand were mainly located in Central and East China, the areas with high supply and low demand were mainly distributed in Northeast China, and the areas with low supply and low demand were mainly located in Western China. The pattern of self-sufficiency of corn in feed grain has remained basically unchanged; the areas with corn feed grain deficit were Central and Southeast China, while North China had corn feed grain surplus. Compared with corn feed, the surplus of soybean feed was relatively poor. Factor detector analysis revealed that in different periods, the same impact factor had different explanatory power in the supply and demand pattern, and the comprehensive consideration of any two factors will enhance the explanatory power of grain supply and demand pattern.

With the rapid development of the aviation industry, many negative effects on the local environment have been reported. This study examined the land use and land cover (LULC) and ecosystem service value (ESV) of airport economic zones (AEZs) in China and assessed the changes in LULC and ESV. The results indicate that LULC changed significantly from 1990 to 2015, characterized by the increase in construction land (increase rate, 68.53%) and water bodies (increase rate, 2.32%) and the decrease in cropland (decrease rate, 4.28%), forest (decrease rate, 0.73%), grassland (decrease rate, 4.64%) and unused land (decrease rate, 6.36%). The ESV of AEZs in 1990 and 2015 was RMB 3454 and 3483 million, respectively, with an overall ESV change of RMB 29 million. The ESV of AEZs is characterized by high value in the coastal area of China. From 1990 to 2015, AEZs with a high ESV were located in Inner Mongolia, while those with a high decrease in ESV were located in the southeastern coastal area. From 1990 to 2000, the AEZs with a high increase in ESV were located in Inner Mongolia and Qinghai and the AEZs with decreased ESV were mostly located in central and south China. However, from 2000 to 2010, AEZs with high and low increases in ESV were located in central China and the south coastal area of China, respectively. From 2010 to 2015, AEZs with a high decrease in ESV were located in southeast China.

Cotton seed production is the main form of agriculture in Xinjiang, China. Unreasonable distribution of cotton seed production results in a waste of water, land, and human resources. In this study, we established a hierarchical classification integrating method; investigated the spatial suitability of climate, land and water resources, and infrastructure; examined the production risk and planting history; and integrated spatial suitability and production risk and history to produce the spatial layout of seed production for early-maturing cotton (EMC), early–medium-maturing cotton (EMMC), and long staple cotton (LSC) in Xinjiang. The results indicated that the appropriate areas for EMC, EMMC, and LSC seed production are 6.4 × 10⁵, 5.5 × 10⁵, and 3.6 × 10⁵ ha, respectively. By combining the suitable areas of seed production for the three cotton species, we concluded that the superior and most suitable area for producing cotton seed of EMC, EMMC, or LSC is located in the western Tarim Basin. The sub-suitable area for cotton seed production of EMC, EMMC, or LSC is mostly distributed in the western and northern Tarim Basin. This research provides a good solution to the selection of cotton seed production base; however, adoption will depend on the actual preference and market factors.

Islands are one of the most sensitive interfaces between global changes and land and sea dynamic effects, with high sensitivity and low stability. Therefore, under the dynamic coupling effect of human activities and frequent natural disasters, the vulnerability of the ecological environment of islands shows the characteristics of complexity and diversity. For the protection of island ecosystems, a system for the assessment of island ecosystems and studies on the mechanism of island ecological vulnerability are highly crucial. In this study, the North and South Changshan Islands of China were selected as the study area. Considering various impact factors of island ecological vulnerability, the geographical information systems (GIS) spatial analysis, field surveys, data sampling were used to evaluate island ecological vulnerability. The Bayesian network model was used to explore the impact mechanism of ecological vulnerability. The results showed that the ecological vulnerability of the North Changshan Island is higher than that of the South Changshan Island. Among all the indicators, the proportion of net primary productivity (NPP) and the steep slope has the strongest correlation with ecological vulnerability. This study can be used as references in the relevant departments to formulate management policies and promote the sustainable development of islands and their surrounding waters