A 28 time-points cropland area change dataset in Northeast China from 1000 to 2020

Abstract. Based on historical documents, population data, published results, remote sensing data products, statistical data and survey data, this study reconstructed the cropland area and the spatial pattern changes at 28 time points from 1000 to 2020 in Northeast China. 1000 to 1600 corresponds to historical provincial-level administrative districts, while 1700 to 2020 corresponds to modern county-level administrative districts. The main findings are as follows: (1) The cropland in Northeast China exhibited phase changes of expansion-reduction-expansion over the past millennium. (2) The cropland area in Northeast China increased from 0.55 × 10⁴ km² in 1000 to 37.90 × 10⁴ km² in 2020 and the average cropland fraction increased from 0.37 % to 26.27 %; (3) From 1000 to 1200, the cropland area exhibited an increasing trend, peaking in 1200. The scope of land reclamation was comparable to modern times, but the overall cropland fraction remained low. The cropland area significantly decreased between 1300 and 1600, with the main land reclamation area was reduced southward into Liaoning Province. From 1700 to 1850, the cropland area increased slowly, and the agricultural reclamation gradually expanded northward. After 1850, there was almost exponential growth, with the cropland area continuously expanding to the whole study area, and the growth trend persists until 2020; (4) The dataset of changes in cropland of administrative districts in Northeast China, reconstructed based on improved historical cropland reconstruction methods, significantly enhances time resolution and reliability. Additionally, the dataset shows the changing characteristics of cropland in Northeast China over the past millennium, especially over the past 300 years, which can provide a refined data base for building a historical cropland gridded dataset.