Runoff and sediment yield on plot

eroded sediment composition

specific surface area(SSA)

and nutrient loss were investigated under field simulated rainfall for two typical shrubs

Caragana korshinkii.and Sophora viciifolia

in the loess gully area.Results showed that both of shrubs can significantly reduce the loss of runoff and sediment.Clay contents

SSA

and nutrient contents decreased with rainfall duration.The organic matter(OM) contents had significant changes with rainfall duration but total phosphorus(TP) contents did not.Clay and nutrient contents in sediment from the two shrub lands were higher than those from the bare lands(CK)

and clay and nutrient contents from the Caragana korshinkii lands were higher than those from the Sophora viciifolia lands

which may be resulted from the influence of vegetation including above-ground and below-ground parts.In addition

sediment could enrich clay and nutrients

and the enrichment ratios increased with vegetation coverage but decreased linearly with runoff time.The enrichment ratios of OM in all the plots were greater than 2.5

while the averaged enrichment ratios of TN and TP were 2.13 and 1.23

respectively.The nutrient contents in sediment correlated positively with the content of clay particles(less than 0.002mm) and the SSA

because soil nutrients are mainly carried by fine particles.The SSA can embody the changes of particle size distribution and soil nutrients.