In this paper

the components of particle sizes and the contents of soil nutrients are used to compare correlation between river sediments and soils from the eroded fields

as well as to assess the soil degradation by soil erosion. The results studied are also used to demonstrate the source and stratum of sediment yield in the drainage area. The mechanical composition of the sediments in the Yellow River and its most tributaries is similar to that of loess deposits in the eroded areas with coarse silts (0.05—0.01mm) and fine sands (0.25—0.05mm) in the predomination. Coarse particles larger than 0.25mm couldn't be seen in the sediments of the Sanmen Gorge dam-site and little amounts there are in the loess deposits. The river sediments of the Huangpuchuan Stream and the Kuyehe River contain considerable amount of coarse particles larger than 0.25mm originated from the local denudated sandrock. Coarse particles larger than 0.25mm can be used to distinguish the stratum of sediment yield. The amount of total nitrogen contents of river sediments in most tributaries is 0.04% on the average

which is close to or higher than the lowest value of those in soils. The contents of available phosphorous in sediments are obviously enriched

and most of them is over those in soils

some even as many as 2—3 times. The enrichment ratio of available phosphorous can be used as an important index to illustrate soil degradation caused by soil erosion. The data of river sediments are obtained in 1983 with lopsided dry season.