The Ecological and Social Effects of Cropland Expansion in the HehuangValley during theMing and Qing Dynasties

In this paper, we strive to showthat the protection of the ecological environment of the Yellow River can impact regional sustainable development and human society. Based on GIS and historical documents, we selected 1640AD in the late Ming Dynasty and 1726, 1746, and 1856AD in the early and middle Qing Dynasty as time sections to reconstruct the distributions of cropland and vegetation in the Hehuang valley. Our results showed that the cropland in the Ming Dynasty was mainly distributed in the valley of Sainei;during the early and mid-Qing Dynasty, the cropland reclamation broke the boundary of the Great Wall. Furthermore, replacing vegetation with cropland resulted in the rapid decline of water conservation capacity in the medium and high mountain areas. The decline of water conservation capacity significantly contributed to the frequent occurrence of natural disasters, such as drought, flood, water erosion, and sand pressure, which led to decreased cropland output. By the mid-Qing Dynasty, the cropland area had saturated while the population was still growing, and the grain yield could not meet the demands of the expanding population. Due to both natural and social factors, two social upheavals occurred in the late Qing Dynasty, which significantly affected the development of the regional social economy. Therefore, the destruction of the ecological environment and the reduction of water conservation capacity became an important driving force for the destruction of sustainable regional development.