Abstract: The study on the effects of different land use patterns on the sediment production in Luergou watershed of Loess Plateau indicated that in comparing with 1982,the areas of forest and grass and of terrace in 1989 increased by 5% and 2.09%,respectively,while that of slope plowland decreased by 1.5%,with the area of naked land and shrubbery respectively increased and decreased a little.During 1998～2000,with the increase of vegetation cover and the decrease of steep slope plowland,the sediment production reduced significantly under high precipitation,85 326 and 52 937 t under the precipitation of 803 and 786 mm,respectively,and not distinguishable in dry years.The reduction effect had a strong seasonality, which consisted with rainfall distribution.For example,in a month with 50 mm precipitation,the mean daily sediment concentration was reduced by 6 kg·m^-3, while in a month with 100 mm precipitation,the reduction was 12 kg·m^-3. Rainfall intensity also played an important role in soil erosion and sediment production,regardless of land use conditions.

Key words: Robinia pseudoacacia forest, Thinning improvement, Thinning intensity