The locust plagues of the Ming and Qing dynasties in the Xiang-E-Gan region, China

Based on the historical documents of Ming and Qing dynasties, with the help of mathematical statistics and the ArcGIS spatial analysis method, this study reconstructed grades and counties affected by locust plagues to examine their spatiotemporal characteristics, environmental significance and social impact. The results show that: (1) There were 242 locust plague years in the Xiang-E-Gan region during the Ming and Qing dynasties, with an average of one outbreak every 2.25 years. The Qing dynasty suffered more than the Ming dynasty, and Hubei Province was affected more seriously than Jiangxi Province and Hunan Province. Locust plagues mostly occurred from March to August, and autumn locust plagues occurred more frequently than summer locust plagues. (2) The sixteenth, seventeenth and nineteenth centuries were periods of successive outbreaks, with 4.13 locust plague years and 10.75 affected counties per decade. The spatial heterogeneity and aggregation of locust outbreaks were significant, and the plain area was affected more seriously and continuously. (3) Low temperature promoted the outbreak of locust plagues, especially during the period of high occurrence, and the outbreaks cannot indicate the previous year’s temperature. Compared with floods, the relationship between droughts and locust plague was closer, and large-scale climate change may also affect locust outbreaks. (4) Long-term natural disasters multiplied the food price and food prices lagged behind disasters. Epidemics were often accompanied by locust plagues, forming a typical chain of agricultural disasters that did great harm to the society.