Study On Community Structure And Biomass Of Xizang Sophora Moorcroftiana

Sophora moorcroftiana which common name is Sophora davidii, Dan Zongmei and stabbed Ma, is a perennial drought-resistant shrub in Leguminosae Sophora. In this paper, Xizang Sophora moorcroftiana was field surveyed and field researched in two years. Focused on Shigatse, Shannan, Lhasa, Nyingchi areas in Xizang province population biomass of Sophora moorcroftiana at different altitudes and habitats were studied in September and October 2009. Mainly using of approach adopted, the standard strains of mining law field collection methods and related laboratory method, trees (bundle) Sophora biomass, Sophora population biomass with elevation, Sophora species biomass with habitat, Sophora root distribution, Sophora ground, part of the dry weight of stem and other relations were analyzed and researched by SPSS17.0. At the same time the structural characteristics of Sophora community was simply analyzed.The main results are as following:First, from the whole, the trees (bundle) Sophora dry weight of various organs in the allocation of ground basic order: stem 48.57%> 30.61% lateral stem> leaf 17.79%> 3.02% fruit. Organs in the allocation did not show significant correlation with the elevation gradient. Sophora aboveground dry weight of the East, West and North direction were distributed relatively large while at least in the South. Shoot dry weight of the vertical distribution: Sophora shoot dry weight concentrated in the range of 20-30cm, covering the part of the total dry weight of 47.86%; dry weight distribution at least in 60-70cm of the crown, not on the ground part of the total dry weight of 1%. In addition to 20-30cm high dry up. Dry weight of other high segment showed a decreasing trend from the base stem to the crown.Second, the trees (bundle) Sophora distribution of dry weight of underground parts: from the root diameter class distribution, the shoot dry weight mainly distributed in the roots than 3mm of the root. From the root direction distribution, the shoot dry weight mainly distributed in the south and north. Shoot dry weight of the vertical distribution: main root dry weight of the stem downward from the base is basically a decreasing trend, while the lateral root dry weight increased with depth did not show significant variation, and shoot dry weight concentrated in the more than 90cm of soil layer, in the 150-160cm of the soil, a larger proportion of lateral root dry weight.Third, Sophora ground biomass and biomass relations, root-shoot ratio is the largest semi-fixed sand dunes Shannan, up to 13.19, followed by Shannan not closed area; Shannan enclosed area is the smallest, that is 0.846. Overall, Sophora buried in sand habitats, in addition to Xietongmen and semi-fixed sand Qiugen Guan Shannan larger than that for 5.47 and 13.19, most of the other shoot ratio less than 1.Fourth, from the altitude and Sophora species biomass allocation, Sophora population biomass which was largest at 3500-3700m is more suitable habitats. The change of Sophora population biomass with altitude is not significant other regions.Fifth, from Sophora total population biomass of view, semi-fixed sand dune, fixed sand dunes and lowland is suitable habitat at different habitats in the Shannan area sand control of degraded land.Sophora-Leptodermis-Artemisia at mountainside in Milin which is more suitable for vegetation types is more suitable habitat for Sophia. From underground and aboveground biomass allocation, ground biomass is greater than 50%when Sophora buried with sand. Ground biomass is less than 50%when Sophora not buried with sand.Sixth, Sophora community structure: Firstly, there are 60 kinds of seed plants in the community, belonging to 31 families, 54 genera. Gymnosperms include 2 families, 2 genera, 2 species. Angiosperms include 29 families, 54 genera, 60 species. (Dicotyledons include 25 families, 40 genera, 46 species. Monocotyledons include 4 families, 14 genera, 14 species). Secondly, Hemicryptophyte is major components of Sophora community where no phanerophyte. Dwarf phanerophyte mainly concentrated in Milin County. Thirdly, Sophora community structure is relatively simple. Ground stratification phenomenon is obvious without tree layer. Sophora is the main components in the herb layer. Except Lang County and Milin County, Sophora is a single dominant species in Shannan, Namulin County and Xietongmen County. Species is affluent in herb layer. Seed plants include 21 families, 40 genera, 43 species. Families which have more species are Gramineae, Leguminosae, Chenopodiaceae, Polygonaceae and Asteraceae. View from life type, the herbaceous layer was evenly distributed where hemicryptophyte was foremos. Finally, there is larger proportion of seedlings in Sophora population. Population regeneration can be achieved. So it is judged that Sophora species showed growth phenomenon.