Urban expansion and its consumption of high-quality farmland in Beijing, China

China faces the challenge of using limited farmland to feed more than 1.3 billion people. Accelerated urbanization has exacerbated this challenge by consuming a large quantity of high-quality farmland (HQF). It is therefore essential to assess the degree to which urban expansion has preferentially consumed HQF, and discern the mechanism behind this. We found urban areas in Beijing to expand at speeds of 48.97 km2/year, 21.89 km2/year, 62.30 km2/year and 20.32 km2/year during the periods 1986-1995, 1995-2000, 2000-2005 and 2005-2020, respectively. We developed an indicator of HQF consumption due to urban expansion, representing the ratio of HQF consumed to its proportion of overall farmland, and found its values were 2.21, 1.57, 1.99 and 1.10 for 1986-1995, 1995-2000, 2000-2005 and 2005-2020, respectively. Thus, although HQF has been overrepresented in the farmland consumed by Beijing's urbanization, this phenomenon has decreased over time. Centralized expansion has contributed greatly to consumption of HQF. Topography and distances to urban and water bodies determine the relative consumption of HQF in urbanization.