Research on cropland data recovery and reconstruction in the Qing Dynasty: Method and case study
2013, 68 (2):
The global environment has changed significantly since the beginning of the human civilization, especially after the industrial resolution when the world population explosion started. Historical land-use and land-cover changes caused by human activities during the last three centuries have been regarded as one of the five key frame issues in the LUCC project. As a country of 5000 years of history, China has its population boom ever since the prime Qing Dynasty (around AD1700), and becomes an area of active land-use and land-cover changes. Currently, there are two global historical land use datasets, generally referred as the "RF datasets" and "HYDE database". However, at the national level, these global datasets have coarse resolutions and inevitable errors. International and domestic scholars tried to reconstruct China's historical land-use and land-cover quantitatively and spatially. But the remarkable differences among their results bring a lot of difficulty to relevant researchers. Considering various factors that influenced the cropland tax records, this study developed a revised system to transfer historical records into real cropland area. Then, to inspect and calibrate these revised cropland area, we built an examination and calibration system from the aspects of population limitation and reclamation trends. Finally, as a case study, we applied the system to Shandong province, reconstructed its cropland data in the Qing Dynasty and obtained three main results. (1) Historical land tax records were not equal to the real cropland area. Despite the fact that the data revised by the first system can pass the population test, it cannot pass the reclamation trends test. (2) To calibrate them through reclamation trends, the revised system should consider the differences in reclamation policy, cropping system and natural conditions among various areas, and build a provincial factor revision form according to its historical situation. (3) In the early period of the Qing Dynasty, the key factor that limited Shandong's cropland growth was labor supply, so the cropland area approached to the labor supply line. As the population grew, cropland area went towards grain demand line. At the end of Qing Dynasty, the cropland yield of Shandong could not meet its requirement. Thus, Shandong turned into a grain importing place in the mid-19th century.
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