Using 137Cs technique to quantify soil erosion and deposition rates in an agricultural catchment in the black soil region, Northeast China

Soil erosion significantly affects the productive black soil region in Northeast China. Quantification of the soil erosion is necessary for designing efficient degradation control strategies. Cs-137 measurements undertaken on 61 sampling points collected within a 28.5 ha agricultural catchment in the black soil region of Northeast China were used to establish the magnitude and spatial pattern of soil redistribution rates as well as sediment budget within the catchment. Estimated soil redistribution rates using the Mass Balance Model 2 (MBM2) ranged from -56.8 to 171.4 t ha(-1) yr(-1) for the sampling points that were verified by means of both runoff plot data and pedological investigation. Erosion generally occurred behind the shelterbelts, especially in the ephemeral gully susceptible areas, while deposition mainly occurred along the shelterbelts and at the catchment outlet. In the study catchment, 69% of the eroded sediments came from the slopes and 31% the ephemeral gullies. Sediments deposited along the shelterbelts at a rate of ca. 78 t yr(-1) and ca. 33 t yr(-1) at the catchment outlet. The gross soil loss rate for the catchment was -4.4 t ha(-1) yr(-1) with a sediment delivery ratio of 53%. The mean rate of -14.5 t ha(-1) yr(-1) in the erosion areas was much higher than the tolerable value, suggesting that effective soil conservation measures are urgently required to reduce the severe black soil loss for sustainable management of the soil resource. (C) 2012 Elsevier B.V. All rights reserved.