Soil Seed Banks Of Haloxylon Ammodendron In Three Site Types Of Gurbantunggut Desert

In this paper, the traditional statistics and geostatistics theory were used to study the horizontal and vertical distribution characteristics of soil seed bank of H.ammodendron, and analyze its correlations between soil seed bank of Haloxylon ammodendron and aboveground vegetation, and spatial heterogeneity in the three site types of Gurbantunggut desert. The difference of seed bank spatial pattern intensity, scale,spatial structure and constitution among three site types were compared. The application of the soil seed bank was explored by seeding and planting experiments. The results were expected to provide a scientific basis for the distribution pattern of seed bank and the regeneration and restoration of H. ammodendron population in Gurbantunggut desert. Basic conclusion are as follows:(1) The average soil seed bank density moved between 16.9 to 122.77 seeds per 100 square meter. In the same area, the average seed bank density of three site types was: Wujiaqu > Shihezi > Jinghe. With increasing of soil depth, soil seed density decreased rapidly in the vertical distribution. The seeds was mainly distributed at 0~1cm soil layer, seldom distribution at the 1~2cm soil layer, and fewer distribution at 2~3cm soil layer.(2) Through research to the relationship between the soil seed bank and aboveground plant diversity,the results showed that the correlation between the soil seed bank capacity and the richness of aboveground plant was significant.(3) The soil seed bank of H. ammodendron obviously have the characteristics of anisotropy and lardge spatial distribution pattern, and the nugget value at 0° and 90° of the direction are higher than the other two directions, which indicating that the spatial pattern intensities of soil seed bank in 0° and 90°direction was stronger than the other two direction.(4) The nugget value at nine sample plots showed an upward trend in general. This showed that the effect of random factors on the spatial patterns of soil seed bank was increased. With the increase of sampling scale(5~25m) at Shihezi, Wujiaqu, the spatial heterogeneity were increased, while the changed spatial heterogeneity was little at Jinghe plots.(5) The ordinary Kriging interpolation showed that the aggregated distribution soil seed bank had clearly variation of density gradient, while the spatial distribution pattern of soil seed bank of H.ammodendron was determined by the distribution of ephemeral plants. The soil seed bank at Shihezi and Wujiaqu plots both showed significantly mosaic features of high and low density, while the seed density was low and relative homogeneous at Jinghe plots.(6) For seeding experiment of H. ammodendron, the survival plant had 12~94 individuals, and the mortality rates were 99.37~99.82%. For forestation experiment of H. ammodendron, the mortality rate was the smallest(47%) as for Wujiaqu and Shihezi the rate were 62~71% and 81~92% at Jinghe. Therefore,the survival rates of H. ammodendron forestation was connected with edaphic types, habitats and vegetation density.