Influence of Slope and Rainfall Intensity on the Rare Earth Elements and Phosphorous Loss from Soil with Surface Runoff

Abstract

Through artificial rainfall experiments,characteristics of exogenous rare earth elements and P loss with surface runoff(both in the water and sediment)during simulated rainfall were investigated under the conditions of various slope gradient(5°,10°,15°,20° and 25°)and different rainfall intensity(43mm/h,83mm/h and 115mm/h).Results showed that majority of rare earth elements(Nd、Ce、La)and phosphorous transport with the soil particles in runoff,which was more than 92%.The total amount of rare earth elements and phosphorous loss in runoff were correlated significantly.Under the different rainfall intensity conditions,loss amounts of rare earth elements and phosphorous were showing a parabola type relation and increasing with the slope gradient.There was a turning point when the slope gradient increased to some extent and the critical gradient ranged from 22° to 26°.