Spatiotemporal change of cultivated land in China during 2000-2020.

Cultivated land is of great significance for ensuring food security. Since the 21st century, China's rapid development has led to urban construction occupying a lot of cultivated land. The understanding of stage characteristics and regional differences needs to be improved. And it is necessary to quantify the temporal and spatial pattern of cultivated land changes since the 21st century. We used the global land cover dataset (GlobeLand30) to investigate the quantity and spatial distribution of cultivated land change in China from 2000 to 2020. The results show that: 1) Over the last two decades, China's arable land has diminished by 54,996 square kilometers. Notably, the arable land loss between 2010 and 2020 was 1.74 times greater than that from 2000 to 2010. This decline has been exacerbated by factors such as the expansion of urban and rural areas, as well as initiatives to revert farmland to forests and grasslands; 2) The eastern coastal regions experienced the most severe net arable land loss, with a net reduction of 42,989 square kilometers from 2000 to 2020, primarily driven by urban expansion; 3) In contrast, the western regions demonstrated the most substantial net increase in arable land, expanding by 11,583 square kilometers from 2000 to 2020, primarily driven by the development of forests and grasslands. It is noteworthy that despite some areas successfully implementing policies to return farmland to forests and grasslands, the ecologically fragile western regions continue to experience accelerated conversion of these natural landscapes into arable land, partly to compensate for the farmland decrease driven by urbanization in the eastern regions. Looking ahead, China's cultivated protection policy must strike a balance between the ecological value of the western region and the economic value of the eastern region.