| Abstract: | Radionuclides are used as tracers of sediments in areas where no plot data or field monitoring data are not available. Caesium-137 can provide important information on both soil loss rates and sediment sources. The 137Cs technique is employed to assess soil erosion rates in forest and grass lands in the Upper Yangtze River Basin, China. The study area includes 6 forestlands and 4 grasslands in 8 counties and cities over the eastern part of the basin. The 137Cs reference inventories ranged from 620.9 Bq m-2 to 2560.3 Bq m-2. For the 6 forestlands, the average 137Cs inventory over a field ranges from 960.8 Bq m-2 to 2560.3 Bq m-2. The average erosion rate is estimated from the 137Cs measurements between 0 to 588 t km-2yr-1. For the 4 grasslands, the average 137Cs inventory ranes from 119.0 Bqm-2 to 869.7 Bq m-2. The average rate of erosion from grassland varies from 0 to 4435 t km2 yr-1. Where the erosion was more severe, the 137Cs inventory was lower. The results showed that there is no clear relationship between 137Cs inventory, slope length and slope gradient on uncultivated land. The erosion rates for uncultivated land and cultivated land is compared. The result indicates that the erosion rates on uncultivated land is much lower than those on cultivated slopes and the severity of the soil erosion is closely related to vegetation cover. |
