Using 137Cs technique to quantify soil erosion and deposition rates in an agricultural catchment in the black soil region, Northeast China
article i nfo 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. 137 Cs 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 susceptibleareas, while deposition mainlyoccurred along the shelterbelts and atthe catchment outlet.Inthestudycatchment,69% oftheerodedsedimentscamefromtheslopes and31% theephemeral gullies. Sedimentsdepositedalongthe shelterbeltsatarateofca.78 t yr −1 andca.33 t yr −1 atthecatchmentoutlet.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 soilconservationmeasuresare urgentlyrequiredtoreducethesevere black soillossforsustainable management of the soil resource.