乌海市几种灌木与土壤养分聚集的关系

植被与土壤资源的空间格局关系可以为植被恢复提供重要信息，对内蒙古乌海市周边地区的不同灌木与不同土壤养分（全氮、全磷、有机质）的空间聚集关系进行研究。在乌海市周边选取9个包含锦鸡儿属Caragana灌木或沙蒿Artemisia desertorum的植被群，在尺度为5 m×5 m样方中建立坐标系，记录每株灌木坐标点，并从坐标原点在样方范围内沿4个方向隔100 cm采集1份土样，测定土样中全氮、全磷和有机质质量分数，将灌木坐标点和每种养分质量分数前20%的土样坐标点代入点格局模型进行分析。结果表明:在草原化荒漠区域，狭叶锦鸡儿Caragana stenophylla（r=250 cm），锦鸡儿Caragana sinica（r=230 cm）和柠条锦鸡儿Caragana korshinskii（r=150 cm）与全氮的关联尺度相对于沙蒿（r=100 cm或r=75 cm）较大；与全磷存在聚集关系的仅有草原化荒漠区域的锦鸡儿（r=50 cm）；在荒漠草原毛刺锦鸡儿Caragana tibetica（r=45 cm）与有机质存在聚集关系；而沙蒿在荒漠草原（r=190 cm）或草原化荒漠（r=200 cm）均能聚集有机质。将点格局模型运用到灌木与土壤养分的空间关系分析中，得到的关联尺度一定程度可以反映灌木的根冠范围，揭示灌木与土壤养分的空间格局关系。

Relationship between shrubs and soil nutrients in Wuhai City

In Wuhai, the environment was destroyed because of its own defects and the exploitation of many mining areas. Therefore, it is very necessary for the region to carry out targeted environmental governance, and the selections of plant species are very important for environmental governance. Soil is indispensable for plant growth. Understanding the spatial pattern relationships between different species and different soil resources is of great reference value for the preliminary selections of plant species, and can also provide very important information for the land managers. In order to achieve these objectives, a classical statistical method-spatial point pattern analysis-was used in this study. It can reflect the correlation and obtain relative scale of research objects. Nine communities were selected according to different vegetation groups in the surrounding area of Wuhai. Three plots of shrubs and three plots of herbage were selected from each group for investigation, and the most statistically significant plot was selected according to the principle of spatial point pattern analysis from the three shrubs plots which have investigated already. Soil samples were collected with the origin of a square coordinateaxis as the reference point. Every soil sample was separated from the other samples by 100 cm, a 0-20 cm soil sample of 1.0 kg was taken, and the specific coordinates of each shrub were determined and recorded. After determining the contents of total nitrogen (TN), total phosphorus (TP) and soil organic matter (SOM) of soil samples, The coordinates with the highest nutrient content of 20% of each resource and the coordinates of Caragana spp. or Artemisia desertorum were calculated by spatial point pattern analysis. Then an aggregated relationship and a relative scale were obtained. Results showed that in the steppe desert of Wuhai, there were aggregated relationships between TN and Caragana spp. or Artemisia desertorum. The relative scale was C. stenophylla (250 cm) > C. sinica (230 cm) > C. korshinskii (150 cm) > A. desertorum (100 cm) > A. desertorumina plot with A. desertorum + Nitraria tangutorum (75 cm). For the C. sinica aggregate with TP, the relative scale was 50 cm, and for the A. desertorum aggregate with SOM, the relative scale was 200 cm. In the desert grassland, the relative scale for C. tibetica aggregate with SOM was 45 cm, and the A. desertorum aggregate with SOM was 190 cm. The relative scale obtained by applying the spatial point pattern analysis to the spatial relationships between shrubs and soil nutrients can reflect the distribution range of roots and crowns of shrubs and reveal the spatial pattern relationship between shrubs and soil nutrients in depth.