Cropland cover change in Northeast China during the past 300 years

Abstract

Land use/cover change induced by human activities has emerged as a "global" phenomenon with Earth system consequences. Northeast China is an area where the largest land cultivation activities by migrants have happened in China during the past 300 years. In this paper, methods including documentary data calibration and multi-sourced data conversion model are used to reconstruct historical cropland cover change in Northeast China during the past 300 years. It is concluded that human beings have remarkably changed the natural landscape of the region by land cultivation in the past 300 years. Cropland area has increased almost exponentially during the past 300 years, especially during the past 100 years when the ratio of cropland cover changed from 10% to 20%. Until the middle of the 19th century, the agricultural area was still mainly restricted in Liaoning Province. From the late 19th century to the early 20th century, dramatic changes took place when the northern boundary of cultivation had extended to the middle of Heilongjiang Province. During the 20th century, three agricultural regions with high ratio of cropland cover were formed after the two phases of spatial expansion of cropland area in 1900s-1930s and 1950s-1980s. Since 1930s-1940s, the expansion of new cultivated area have invaded the forest lands especially in Jilin and Heilongjiang Provinces.past 300 years, Northeast China, cropland, land cover, environmental change

Spatially precise reconstruction of cropland areas in Heilongjiang Province, northeast China during 1900–1910

“…The total area of arable land was about 25,397 km 2 , accounting for 5.61% of Heilongjiang in this period. Our estimation is similar to that of Ye et al (2009), who estimated that 5.4% of Heilongjiang was arable land during 1900-1910. This estimated fraction of cropland area at the county level has a spatial pattern characterized by more cropland in the center of the province and less cropland in the surrounding areas.…”

“…Other areas, especially the northern and eastern parts of the study area, were much less developed. Ye et al (2009) have reported the spatial distribution of cropland at the county level based on the present county boundaries. To compare our results with those of Ye et al (2009), we recalculated the fraction of cropland area at the county level based on the present counties using our reconstructed data.…”

“…Ye et al (2009) have reported the spatial distribution of cropland at the county level based on the present county boundaries. To compare our results with those of Ye et al (2009), we recalculated the fraction of cropland area at the county level based on the present counties using our reconstructed data. Table 2 shows that our estimation was in the same range of that of Ye et al (2009) for 65 counties (83.3% of the total number of counties).…”

“…Keeping the relative spatial weights unchanged, the historical national level cropland area was then allocated into grid cells (Ramankutty and Foley, 1999). A static spatial pattern during past centuries is unlikely to be a reasonable model for northeast China because this region has undergone tremendous development since the mid-19th century and the spatial weights of cropland in the past are therefore much lower than at the present time (Ye et al, 2009;Li et al, 2010).…”

“…There are also some published reconstructions specific to northeast China. Ye et al (2009) estimated the area of cropland for each county with an interval of 50-100 years for the last 300 years using local historical documents. As a result of using local records and the experience of histo-rians to translate these historical records, this estimation has a lower uncertainty than previously published work.…”