坡度与雨强对磷和稀土元素径流输出的影响研究

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

通过系列室内人工降雨模拟试验,观察了不同坡度(5°、10°、15°、20°、25°)和不同降雨强度(43mm/h、83mm/h、115mm/h)组合条件下,3种外源稀土元素Nd、Ce、La和磷素随土槽坡面径流输出的特征.结果表明,92%以上的外源稀土元素和磷素都是以径流颗粒物形式输出,且3种外源稀土元素与磷素随径流输出的总量均呈极显著的相关性;在不同雨强下,外源稀土元素和磷素随径流流失总量与坡度呈二次抛物线型关系,即随坡度增大而增大,但土槽坡度增加到一定程度时存在转折点,临界坡度的变化范围为22—26°.

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°.