Abstract: Haloxylon ammodendron was a common small tree of the Badain Jaran Desert， its sandy soil is of the great significance to the growth and development of Haloxylon ammodendron. In this study,the Tamusu wild Cistanche deserticola on the eastern edge of the Badain Jaran Desert and the sandy soil under the Haloxylon ammodendron forest in the test area of the Haloxylon ammodendron seed production base were studied. Representative large sample plots were selected and mechanically sampled by means of multifractal and multi-fractal analysis. The results showed that,the sandy soil under the Haloxylon ammodendron forest in the Badain Jaran Desert was dominated by fine sand (φ≤0.25 mm) and medium sand (0.25<φ≤0.5 mm),accounting for more than 95%. The spatial distribution of fine and medium sand in different sand layers could be mutual token with multifractal and joint multifractal characteristics. The spatial distribution of fine sand and medium sand provided the necessary soil matrix and water conditions for Haloxylon ammodendron;the randomness distribution of coarse sand and the complexity of the small probability subsets distribution of fine sand and medium sand provided diverse niches for the invasion and survival of other species.On the whole,the spatial distribution of sandy soil under Haloxylon ammodendron was dominated by fine sand and medium sand,and the landscape characteristics were determined by the big probability subset. The small probability subsets of fine sand and medium sand with the randomness spatial distribution of the coarse s provided diverse niches for plant survival.

Key words: Sandy soil, Multifractal, Combined multifractal, Haloxylonammodendron forest, Badain Jaran Desert

摘要： 梭梭（Haloxylon ammodendron）是巴丹吉林沙漠常见的小乔木，其林下沙质土壤对梭梭的生长发育具有重要意义。本研究以巴丹吉林沙漠东缘的塔木素野生肉苁蓉（Cistanche deserticola Ma）及梭梭产籽基地的沙质土壤为对象，选定代表性大样地并进行机械取样，结合多重分形和联合多重分形分析，结果表明：巴丹吉林沙漠梭梭林下沙质土壤以细沙（φ≤0.25 mm）和中沙（0.25<φ≤0.5 mm）为主，占比高达95%以上；二者在不同沙层空间分布状态可以互相表征，具有多重分形和联合多重分形特征。细沙和中沙空间分布为梭梭林提供了必要的土壤基质和水分条件；粗沙空间分布的随机性以及细沙、中沙小概率子集空间分布复杂性为其他物种入侵和生存提供了多样化的小生境。整体上，梭梭林沙质土壤以细沙和中沙空间分布占主导，大概率子集决定景观特征，其小概率子集和粗沙空间分布的随机性为植物生存提供了多样化的小生境。

关键词: 沙土, 多重分形, 联合多重分形, 梭梭林, 巴丹吉林沙漠