科尔沁沙地退化草场土壤养分的空间结构分析

Spatial structure of soil nutrients of degraded grassland in southeastern Keerqin sand land and its ecological explanations

利用地统计学的方法对科尔沁沙地东南缘退化草场土壤养分的空间分析表明:该草场土壤有机质、全氮、全磷和速效钾都具有明显的空间结构特征,但结构异质性的程度和尺度表现各不相同,空间相关度依次为0.788,0.470,0.758和0.650,变程依次为7.8,18.4,5.9和6.5m,分数维依次为1.857,1.881,1.933和1.920。Moran'sI系数在近距离(1～2m)内均在0.4左右,随着距离增大,迅速减少,克立格制图进一步形象地直观描述该地退化草场土壤特性的空间结构特征。指出土壤全氮是该地区草地生态系统退化和恢复关注的重点。

Spatial analysis of soil nutrients of degraded grassland in southeastern Keerqin sand land was carried out using geostatistics. The results showed soil organic matter, total N, total P, and rapidly available K all had clear spatial structure characteristics, but their ranges and scales of structural heterogeneity showed difference. The spatial autocorrelated variations of soil organic matter, total N, total P, and rapidly available K were 0.788, 0.470, 0.758, and 0.650, respectively. The ranges were 7.8, 18.4, 5.9, and 6.5 m, respectively; and fractal dimensions 1.858, 1.881, 1.933, and 1.920, respectively. Moran's I coefficients were about (0.4) within close distance (1-2 m). The different spatial structure characteristics of the soil properties were proved again by Kriging maps. After discussing the relationships between the spatial structure characteristics of the soil properties and ecological processes, we recognized that soil total N was key in looking at grassland (ecological) system restoration in this area.