The spatial reconstruction of 5 ′ × 5 ′ cultivated land cover in the three provinces of Northeast China in the Qing Dynasty based on historical settlements and reclamation sites

Improving the gridded reconstruction method of cultivated land is a core issue and difficulty in current research on historical Land Use and Land Cover Change (LUCC). Exploring the gridded allocation method of cropland in Northeast China during the Qing Dynasty can provide a reference for it. Based on the historical settlement data from the Chinese Historical Geographic Information System (CHGIS), the data of reclamation sites in Northeast China during the Qing Dynasty (1644-1911), and the data of natural reclamation suitability, combined with relevant historical materials, this paper designs a gridded allocation model of cropland in Northeast China during the Qing Dynasty that integrates the temporality of reclamation and land reclamation suitability. It reconstructs the spatial pattern of cropland cover with a spatial resolution of 5′ × 5′ in Northeast China in 1683, 1735, 1780, 1820 and 1911 of the Qing Dynasty, qualitatively and quantitatively evaluates the accuracy and rationality of the reconstruction results, and analyzes in detail the changing characteristics of the cultivated land pattern in Northeast China during the Qing Dynasty. The study finds that: (1) Evaluations show that compared with provincial-level data, the grid allocation results of prefecture/county-level cropland data are more consistent with the regional historical records of the five periods, can more accurately reflect the regional differences in cropland distribution in Northeast China, and are particularly applicable to the reconstruction of the late Qing Dynasty cropland pattern. (2) After nearly 300 years of reclamation, the overall reclamation rate of the three northeastern provinces was close to 10%, with the proportion of cropland grids reaching 81.0% (95.6% in Liaoning, 95.0% in Jilin, and 78.1% in Heilongjiang respectively). The focus of reclamation shifted northward. After 1860, relying on the policy inclination of the Qing government, central Jilin and Liaoning .......（The content is folded due to excessive length）