民勤绿洲-荒漠过渡带土壤粒径分形特征研究

The Fractural Characteristics of Soil Particle Size in the Oasis-Desert Transition Zone of Minqin

通过野外采样与室内试验,分析了民勤绿洲-荒漠过渡带土壤粒径分布分形特征及其与土壤理化性质的关系,结果表明:(1)民勤绿洲-荒漠过渡带白刺群落土壤以细砂为主,梭梭、沙拐枣群落土壤以中砂、粗砂为主;土壤粒径分形维数为2.144～2.398,3种植被类型土壤粒径分形维数均为固定沙丘>半固定沙丘>流动沙丘(或平沙地>流动沙丘)。(2)土壤粒径分形维数与黏粒(<0.005 mm)、粉粒(0.005～0.05 mm)含量呈极显著正相关(p<0.01),与细砂(0.1～0.25 mm)、中砂(0.25～0.5 mm)、粗砂(0.5～1 mm)含量呈负相关但不显著,与极细砂(0.05～0.1 mm)、极粗砂(1～2 mm)含量呈正相关但也不显著。(3)分形维数D值与全氮、速效磷含量分别呈极显著正相关(p<0.01)和显著正相关(p<0.05),土壤黏粒含量与有机质、全氮、速效磷含量呈显著正相关(p<0.05),土壤粉粒、砂粒含量与有机质含量呈极显著正相关(p<0.01),土壤分形维数D值和黏粒、粉粒、砂粒含量与土壤含水量、全钾、速效钾、全盐、p H值相关关系均不显著。

The paper analyzed the fractural characteristics of soil particle size distribution and relationships between fractal dimension D and soil physicochemical characteristics in Minqin oasis-desert transition zone through filed sampling and laboratory experiments. The outcomes show that a) the Nitraria tangutorum community soil of Minqin oasis-desert transition zone mainly is fine sand. The soil of Haloxylon ammodendron community and Calligonum mongolicum community mainly is medium-sized sand and coarse sand. The fractal dimension of soil particle size is2.144-2.398. The fractal dimension of soil particle size of 3 types of vegetation all shows fixed sand dune > semi fixed sand dune > moving sand dunes( level sand land > moving sand dunes); b) the fractal dimension and the contents of clay( <0.005 mm) and silt( 0.005-0.05 mm) have very significant positive correlation( p<0.01),and fine sand( 0.1-0.25 mm),medium-sized sand( 0.25-0.5 mm) and coarse sand( 0.5-1 mm) are negatively correlated but not significant,and extra-fine sand( 0.05-0.1 mm) and extra-coarse sand( 1-2 mm) are positive correlation but not significant and; c) the D value of fractal dimension and the contents of total nitrogen and available phosphorus show extremely significant positive correlation( p<0.01) and significant positive correlation( p<0.05),the content of clay and the contents of organic matter,total nitrogen and available phosphorus show significant positive correlation( p<0.05),the contents of silt and sand and the content of organic matter show extremely significant positive correlation( p<0.01). The correlation of the D value of fractal dimension and the contents of clay,silt and sand and oil moisture,total potassium,available potassium,total salt and pH value are not significant.