Abstract:

In rocky desertification areas， the bedrock is bare， gravel is piled up， soil and water loss is serious， soil and vegetation coverage is low， which leads to a series of ecological deterioration problems.The restoration of vegetation by soil dressing is a fast and effective way.The experiment was carried out in Bijie， Guizhou province. The local yellow soil was used to soil dressing for rocky desertification. The Hippophae rhamnoides seedling which can resist the low fertility was selected as the test material. The adaptability of the H. rhamnoides seedlings on different degrees of soil dressing for rocky desertification was mainly explored in this experiment. Four treatments were set up for different degrees of soil dressing：T1 （yellow soil to gravel ratio： 1∶1）， T2 （yellow soil to gravel ratio： 2∶1）， T3 （yellow soil to gravel ratio： 3∶1） and T4 （yellow soil to gravel ratio： 1∶0）.The results showed that there was no significant effect on the crown width， root length density and root weight density under different treatments；T4 which is all of yellow soil could restrict the plant height and root biomass significantly， and promote the root length of fine root significantly.The root weight density and soil water content of the fine roots increased significantly after two years as the yellow soil and gravel ratio was between 1/2 and 2/3，while the ratio of yellow soil to gravel was more than 2/3， the total root length and the final soil water content were inhibited significantly. Person correlation analysis found that the root index was significantly correlated with the final soil water content.In conclusion， the experiment shows that the ratio of the yellow soil should be controlled when the H. rhamnoides seedlings was planted on different degrees of soil dressing for rocky desertification soil dressing in Bijie， Guizhou province. And the final soil water content which can be improved after two years under the treatment of yellow soil to gravel ratio is between 1/2 to 2/3.

Key words: soil dressing, rocky desertification, Hippophae rhamnoides, soil water content