Soil erosion in relation to climate change and vegetation cover over the past 2000 years as inferred from the Tianchi lake in the Chinese Loess Plateau

摘要

Understanding the response of past soil erosion to climate change and human disturbances is quite essential for managing and preventing soil erosion in the future. Here, we report a high-resolution soil erosion sequence during the past 2000 years based on grain-size data from a sediment core GS07A in Tianchi Lake in the Chinese Loess Plateau. These grain-size data are analysed by end-member modelling and further deciphered by detailed modern investigations of surface sediments, surface soils, and modern dust samples aided by published grain-size distribution characteristics of different depositional provenances and processes. Six strong soil erosion periods, including more than 20 serious soil erosion events, are inferred at 150-300 CE, 450-750 CE, 900-1100 CE, 1200-1400 CE, 1650-1800 CE, and 1950-2000 CE. These soil erosion records correspond well with intensive flood events in downstream rivers and the neighbouring Longxi area documented from the historical literature, suggesting that regional high-intensity rainfall or flood events are the main cause of soil erosion. Vegetation cover in the catchment also influenced soil erosion: light vegetation cover aggravated soil erosion even in the periods with a low frequency of flooding, while heavy cover reduced soil erosion even in the periods with a high frequency of flooding. Our results highlight the role of sustainable land use and vegetation restoration around the catchment in controlling soil erosion in the Chinese Loess Plateau.