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The black soil region of northeast China, which covers the Provinces of Heilongjiang, Jilin and the Inner Mongolia autonomous region with black soil, chernozem and meadow soil, has experienced soil erosion since intense agricultural reclamation began approximately 100 years ago. However, the sediment delivery ratio, defined as the fraction of gross erosion that is transported from a given area in a given time interval, is still unclear. In this study, we calculated the delivery ratio and analysed changes in erosive processes within Hebei catchment from 1977 to 2007 based on an analysis of sediments of the Liudui reservoir. The original vegetation layer clearly identified the bottom of the reservoir when it was constructed in 1977; thus, the reservoir sediments could be precisely dated. The delivery ratio, calculated by comparing the sediment deposition in the reservoir with the total soil erosion in the upstream catchment, was found to be exponentially correlated (r2 = 0.95, P < 0.01) with decreasing grain size, except for the fraction |
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