The sediment sources in smallwatershedswere analyzed based on studies in a watershed in western Shanxi Province of the Loess Plateau.On the basis of watershed classification

seven typical watersheds were chosen and observed for 14 years.Results show that the sediment yield of small watersheds comes mainly from gullies (60% of the total sediment load).Erosion soures of the valley(including gully heads

gully beds

and valley sides)are 1.28～2.48 times more significant as sediment sources than the interfluves(including hill slopes and hill tops).Cultivation of slopland and bare soil are key contributors to soil erosion.