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采用经典统计学和地统计学方法,通过半变异函数及其模型、克里格局部插值估计、空间分布图及分形维数等对宁夏盐池沙地3种植物群落(牛枝子、牛枝子-黑沙蒿、黑沙蒿)土壤表层养分的空间异质性进行了研究。结果表明:0～5cm土壤有机质、全氮、速效磷含量的空间自相关尺度分别是67m、519m、143m;结构方差比分别为0.558、0.882、0.514,说明结构性因素和随机性因素在0～5cm土壤有机质和速效磷的空间分布中共同发挥作用。全氮表现出较强空间自相关性,在空间分布上具有明显的结构特征,表明结构性因素在其空间总变异中发挥主导作用。空间格局图反映出0～5cm土壤有机质、全氮含量表现为牛枝子群落较高,经牛枝子-黑沙蒿群落,含量逐渐减少,至黑沙蒿群落含量又有所增加;0～5cm土壤速效磷含量表现为牛枝子群落和黑沙蒿群落含量较高而牛枝子-黑沙蒿群落含量较低的趋势。反映出研究区从牛枝子群落经牛枝子-黑沙蒿群落至黑沙蒿群落,植被从以草原种为主的群落,逐渐灌木化,植物群落结构组成由复杂到简单的过程,深刻影响了土壤养分的分布格局,导致了土壤“肥力岛”的形成和发展,又反作用引起研究区植物群落的进一步灌丛化,并逐步向沙漠化的方向发展的趋势。
By using the methods of classical statistics and geostatistics, the three plant communities (Niuzhizi, Niuzhizi - Black) in Yanchi sand land of Ningxia were studied by means of semivariogram and its model, Kriging local interpolation estimation, spatial distribution and fractal dimension, Artemisia sphaerocephala and Artemisia sphaerocephala) were studied. The results showed that the spatial autocorrelation scales of soil organic matter, total nitrogen and available phosphorus in 0 ~ 5cm soil were 67m, 519m and 143m respectively, and the structural variance ratios were 0.558, 0.882 and 0.514 respectively, indicating that the structural and random factors were between 0 ~ Spatial distribution of 5 cm soil organic matter and available phosphorus play a role. Total nitrogen showed strong spatial autocorrelation, with obvious structural features in spatial distribution, suggesting that structural factors play a leading role in their total spatial variability. Spatial pattern maps of 0 ~ 5cm soil organic matter showed that the total nitrogen content was higher in the cattle branch community, and the content decreased gradually to the community of Artemisia lanceolata, while the content of 0 ~ 5cm soil increased The content of available P showed the trend of higher content of cattle grafted plant and Artemisia annua and lower content of Artemisia scoparia-Artemisia annua. The results showed that in the study area, from the branch of cattle and grasses to the community of Artemisia gmelinatus, Artemisia bracteatum and Artemisia haitanensis community, the vegetation shrubs gradually from grassland-dominated community and the plant community structure changed from complex to simple process, The distribution pattern of soil nutrients led to the formation and development of soil fertility island and the reverse reaction caused the further shrubification of plant communities in the study area and the gradual trend toward desertification.