Pattern of biological soil crust and its driving factors under Artemisia ordosica in Mu Us Sandy land.

The distribution of biological soil crust under Artemisia ordosica in the Mu Us Sandy land is studied by means of line transect sampling,and the pattern of biological soil crust and its driving factors are analyzed.The results show that the thickness of biological soil crust under Artemisia ordosica is uneven.The maximum thickness,0.84 cm,occurs at the position of 20 cm from the basal root.Outward from the position,the thickness of biological soil crust reduces in ring by a rate of 0.07cm every 10 cm.The radius of biological soil crust is longer southeastward than that in the other three directions,while that northwestward is shorter.The biological soil crust is the thickest southeastward and thinnest northwestward.The analysis shows a significant correlation between the distribution of litterfall and biological soil crusts under Artemisia ordosica,suggesting litterfall is an important factor to accelerate the development of biological soil crust.The pattern of litterfall is controlled by the local wind regime and the canopy shape of Artemisia ordosica.