Preferential encroachment of high-quality cropland by urban expansion across China: Past trends and future projections

The reduction of high-quality cropland poses a more severe threat to food security (FS) than that of ordinary cropland. However, large-scale quantitative assessments of the impact of urban expansion on high-quality cropland is insufficient. This study introduces the concept of “consumption preference,” defined as the propensity of urban land to preferentially occupy high-quality cropland during expansion, and develops a county-level indicator of high-quality cropland consumption (IHC) preference to systematically analyze trends in urban land occupation from 1980 to 2050 and project future scenarios. The main findings are as follows: (1) Between 1980 and 2020, China's high-quality cropland declined by 11.56 %, with its proportion decreasing from 58.01 % to 50.97 %, whereas the total cropland area remained generally stable (increasing by 0.65 %) but exhibited a substitution pattern whereby low-quality cropland compensated for high-quality losses. (2) The proportion of counties with considerable IHC increased by 30.03 % from 1980 to 2010, then declined by 3.13 % from 2010 to 2020. Spatially, the central region exhibited the highest proportion (49.61 %), whereas the Northeast had the lowest (19.24 %). (3) Scenario simulations indicate that by 2035, cropland area is projected to increase by 0.54 %, 20.00 %, 20.00 %, and 21.32 % under the Business-as-Usual (BAU), Economic Development (ED), Ecological Protection (EP), and FS scenarios, respectively; by 2050, the increases will reach 1.22 %, 39.74 %, 31.21 %, and 36.42 %, respectively. (4) From 2035 to 2050, the proportion of counties with considerable IHC shows a declining trend across all scenarios, with average annual decreases of 3.82 % and 1.01 % (BAU), 1.14 % and 0.61 % (ED), 1.79 % and 2.17 % (EP), and 1.07 % and 0.93 % (FS). Overall, although the trend of preferential occupation of high-quality cropland by urban land is gradually moderating, the Northeast region continues to experience substantial risks under all scenarios, highlighting the urgency of region-specific protection strategies. • Proposed a method to assess HQC at county scale using farmland production potential. • Developed the IHC index to assess urban land expansion's preference for HQC. • Quantified urban expansion's preference for HQC since 1980. • Revealed a nationwide shift in IHC from rising to declining after 2010. • Identified northeast China as a key risk area for future cropland loss.