黑河中游荒漠-绿洲过渡带固沙植物根区土壤颗粒组成及分形特征

Fractal Characteristics and Particle Composition of Soil in the Root Zone of Sand Fixing Plants in the Transitional Zone between Desert and Oasis in the Middle Reaches of the Heihe River

探究荒漠-绿洲过渡带固沙植物根区土壤颗粒分布及分形特征,可对区域生态植被建设和荒漠化防治提供一定理论依据。选取黑河中游的荒漠-绿洲过渡带内3种固沙植物作为研究对象,采集固沙植物根区0~120 cm土层的土壤样品,测定了土壤粒度组成,并计算了土壤颗粒分形维数D。结果显示:3种固沙植物根区土壤的颗粒以中砂粒(0.25~0.5 mm)和细砂粒(0.1~0.25 mm)为主,占比75%以上,除中砂粒和细砂粒外,不同粒级土壤颗粒质量分数由高到低为极细砂粒>粗砂粒>粉粒>黏粒;3种固沙植物根区的土壤颗粒组成存在显著差异(P<0.05),沙拐枣根区土壤细砂粒和极细砂粒质量分数显著高于泡泡刺和梭梭,泡泡刺根区土壤中粉粒和黏粒质量分数显著高于梭梭和沙拐枣;3种固沙植物根区土壤颗粒分形维数D也存在显著差异(P<0.05),泡泡刺(2.00)>梭梭(1.94)>沙拐枣(1.91),且浅层(0~60 cm)土壤易受外界因素干扰,土壤颗粒分形维数D变化幅度较大;土壤颗粒分形维数D与土壤颗粒中的黏粒和粉粒质量分数呈极显著的正相关关系,与土壤中颗粒的砂粒质量分数呈极显著负相关关系,土壤颗粒分形维数D能较好地体现研究区固沙植物根区的土壤颗粒组成。提高固沙植物数量和覆盖率对于沙化土壤固定,改善土壤质量,防止风蚀的发生均具有重要意义。

Exploring the fractal characteristics and distribution of soil particles in the root zone of sand fixing plants in the desert oasis transition zone can provide a theoretical basis for regional desertification prevention and ecological construction.Three types of sand fixing plants(Nitraria sphaerocarpa,Calligonum mongolicum,and Haloxylon am-modendron)were selected in the transitional zone between desert and oasis in the northern part of Linze County as the research objects.Samples of soil were collected from the root zone of sand-fixing plants,within the 0~120cm soil layer.The composition of soil particle sizes was measured,and the fractal dimension(D)of the soil particles was subsequently calculated.The results indicate that the soil particles within the root zone of three sand-fixing plants are mainly medium sand(0.25~0.5mm)and fine sand(0.1~0.25mm)Mainly,accounting for over 75%,with the lowest content of clay particles;Except for medium sand and fine sand,the contents of different size particles de-creased in the order:extremely fine sand>coarse sand>silt>clay;Distinguishable disparities(P<0.05)were evi-dent in the soil particle composition within the root zone of the three sand-fixing plants.The content of fine and ex-tremely fine sand particles in the soil of the root zone of Calligonum mongolicum were significantly higher than those of the Nitraria sphaerocarpa and Haloxylon ammodendr on.The content of fine particulate matter in the soil of the root zone of Nitraria sphaerocarpa is significantly higher than that of Calligonum mongolicum and Haloxylon ammo-dendron;There were also significant differences in the fractal dimension D of soil particles in the root zone of the three sand-fixing plants(P<0.05),Nitraria sphaerocarpa(2.00)>Haloxylonammodendron(1.94)>Calligonum mongolicum(1.91),and shallow(0~60cm)soils were easily disturbed by external factors,and the fractal dimen-sion D of soil particles underwent substantial changes.The fractal dimension D of soil particles exhibits a strong pos-itive correlation with the quantity of clay and silt in the soil.Conversely,it demonstrates a pronounced negative corre-lation with the quantity of sand particles in the soil.The fractal dimension D of soil particles can effectively demon-strate the characteristics of soil particle composition in the root zone of sand-fixing plants.Improving the number and coverage of sand fixing plants is of great significance for fixing sandy soil,improving soil quality,and preventing wind erosion.