Understanding impacts of cropland pattern dynamics on grain production in China: A integrated analysis by fusing statistical data and satellite-observed data.

Detailed information on spatial distribution of croplands and grain yields is crucial for agricultural management and food security, but is often limited by a lack of geospatial data. By integrating satellite observation and statistical data, this study produced new geospatial data of cropland areas and grain yields in China during 2000-2020. We found that the decrease of relatively high-yielding croplands in southern China mainly caused by the expansion of constructed land. Yet, the increase of croplands largely occurred in temperature/water-limited regions of Northern Arid and Semiarid Region (NASR) and Northeast China Plain (NCP). Croplands' decrease in southern China and expansion in NCP and NASR jointly led to the continuous northward shift of the centre of gravity of croplands and grain yields. This spatial transfer of croplands resulted in relatively lower-than- average grain yield per unit area (AGYA) croplands decreasing from 38.96% (2000) to 35.75% (2020), but also relatively higher-than-AGYA croplands decreasing from 38.41% (2000) to 35.01% (2020), implying spatial challenges of grain production. Generally, every 1 km2 of cropland loss in traditional high-yield zones required nearly 1-3 times expansion in area in NASR and NCP to balance grain yield losses. The new geospatial data and these findings from this study could provide valuable information for regional agriculture development and policy marking.