Roots' Distribution Characteristics And Fine Root Dynamics Of Sabina Vulgaris And Artemisia Ordosica In Mu Us Sandland

Mu Us sandland is a fragile ecological band from arid zone to semi-arid zone. It attracted many scholors'attention widely. S. vulgaris and A.ordosica had important functions for keeping the landscape and the balance of ecological system. It has been focused, however, the root system, as an important section, was not valued properly until nonce. And people only noticed their vertical and horizontal distribution generally at a fixed time. But it was not reported about seasonal change of fine root. By coring and classifying the root systems, this paper mainly reported the investigation and research on dynamic characteristics of root systems of S. vulgaris and A.ordosica which grew in northern site of exploitation and research centre of Mu Us sandland. Seven sample plots were selected base on their natural appearance; the natural flora was classified into three major parts: S. vulgaris community, S. vulgaris cluster and A.ordosica community. Collecting sample from each plot, simultaneously measured the water-content in volume of the soil and analyzed the data, the results were as following:1. Diameter scale percentage: S. vulgaris community had the biggest biomass of its root systems; oppositely, A.ordosica community had the smallest. Different diameter scale root systems had different percentage in total root biomass: thick roots had maximum percentage in S. vulgaris community and the minimum happened in A.ordosica community mediate roots appeared similar percentage in three of them; fine root have the biggest percentage in S. vulgaris cluster, minimum percentage in S. vulgaris community. Dead roots had the maximum percentage in A.ordosica community, minimum in S. vulgaris cluster.2. Vertical distribution of the fine root:βof S. vulgaris and A.ordosica was around 0.96, annual average showed, the biggest biomass of fine roots appeared 0~15cm. fine roots were gradually reduced with the depth. Percentage of the fine root of S. vulgaris community , S. vulgaris cluster and A.ordosica community had similar vertical arrangement characters, annual average fine root biomass of corresponding layers show as S. vulgaris cluster>S. vulgaris community> A.ordosica community.Root Length Density (RLD) and Root Area Index (RAI) of fine root appeared similar rule on depth, and annual average maximum values happened in 0~15cm, the values reduced with the depth. The order of the total RAR of fine root was: S. vulgaris cluster>S. vulgaris community>A.ordosica community.