Study on the Distribution of Root System of Hippophae rhamnoides on the Slope in Sandstone Area

After researching on the distribution characteristics of the root system of China Hippophae rhamnoides which had been planted on the slope in sandstone area,and analyzing their indices(root density,root length and root weight) in different diameters,this article finally reveals that most of Hippophae rhamnoides roots mainly distributed within 0-40 cm soil depth,and in this shallow dist ributional type,the level roots were rather flourishing.With root diameter less than 3 mm,the maximum of its root density can reach the surface and then diminished when the soil depth became more and more deep.Whereas,to the root diameter which is more than 3 mm,the value of root density can reached the maximum in the depth of 10-20 cm and diminished with the soil depth.With the increasing of root diameter,root length took on the trend of decreasing,on the contrary,root weight became increasing when the root diameter increased.The root nodule,which mainly distributed within 0-40 cm soil depth,has the capacity of fixing nitrogen,and its value can reached the maximum on the surface.