Objectives Cultivated lands are the lifeblood of food production, and maintaining a stable cultivated land area is the foundation for guaranteeing the food security strategy. We studied the spatial and temporal changes of cultivated land reserve resources in China, aiming to provide a reference for the comprehensive protection and management of cultivated land resources.

Methods The Resource and Environment Data Center of Chinese Academy of Sciences uses Landsat remote sensing image data as the primary data source and employs manual visual interpretation at a national scale to construct a Land Use and Land Cover data set. Based on this database, this study divided China into the Northeast, North China, the middle and lower reaches of the Yangtze River, Northwest, Southwest, and Southeast regions, and used the GIS spatial overlay analysis method to analyze the area changes and spatial distribution patterns of cultivated land reserve resources in China in 2000, 2010, and 2020.

Results In 2000, 2010, and 2020, the areas of cultivated land reserve resources (CLRR) in China were 117.75 million hm², 118.03 million hm² and 129.32 million hm² respectively. The largest CLRR areas were in the northwest and southwest regions of China, while the lowest area was in the middle and lower reaches of the Yangtze River. During the period of from 2000 to 2010, and 2010 to 2020, the overall trend of the CLRR area was increasing. The CLRR increased by 0.29 million hm² from 2000 to 2010, and by 11.29 million hm² from 2010 to 2020, but resource area varied greatly among different regions. During the period of 2000 to 2010, the CLRR decreased merely in North China and Northwest China, and Northwest decreased more than North China. During the period of 2010 to 2020, however, the decreasing of CLRR area occurred in all the Southeast, Northwest, North China, and Northeast regions, with the largest decrease still in the Northeast. Balance analysis indicated that the conversion of grasslands and unused lands to cultivated lands increased the overall cultivated land area, while construction activities led to a net loss of cultivated land during the study period.

Conclusion The situation of cultivated land protection in China is still urgent. In addition, the regional distribution of the cultivated land reserve resources is extremely unbalanced, narrowing the space for compensating lost cultivated land. For the development and utilization of the cultivated land resources, local ecological conditions should be seriously considered to strengthen the supervision of key areas and uses of cultivated lands.