Reconstructing cropland change since 1650 AD in Shaanxi province, central China

摘要

Regional reconstructions of historical cropland change are essential to improve the accuracy of global datasets. In Shaanxi province, central China, frequently affected by rebellions and natural disasters over the past 300 years, the cropland area fluctuated. In this study, based on local gazetteers, statistics, and survey data, systematic steps are followed to reconstruct the cropland area change since 1650 in Shaanxi province. The result shows four stages of changes in the total cropland area: steady increase during 1650-1830 stimulated by policies and population growth, decrease during 1830-1937 affected by wars and natural disasters, rapid growth during 1937-the 1980s, and rapid decrease after the 1980s influenced by urbanization and the agricultural planting structure adjustment. The total cropland area increased from 2.2 x 10(4) km(2) in 1650 to 3.99 x 10(4) km(2) in 2016. The majority of the cropland concentrated on the Guanzhong region from 1650 to 2016. The cropland expanded from the center to the surroundings in the Guanzhong region, from northeastern to southwestern in northern Shaanxi, and from western to eastern in southern Shaanxi before the 1980s. Cropland area declined in all three regions after the 1980s. The comparisons show most cropland area data in the Qing dynasty from the existing regional studies are still highly dependent on the registered tax-paying cropland area. Without considering agricultural history, changes in the SAGE cropland in Shaanxi province over the past 300 years are irrational. Spatially, HYDE 3.2 dataset cannot show the "real " spatial distribution of the cropland before 1930, because too much cropland is allocated to northern and southern Shaanxi.