松嫩平原西部典型盐生景观土壤分形维数及盐碱化特征

为探究松嫩平原西部典型盐生景观土壤颗粒粒度组成及分形特征与土壤盐碱化之间的关系,采用体积分形维数模型计算了6种典型盐生景观土壤表层0—30 cm颗粒组成及分形维数,结合相关分析法分析了土壤分形维数与质地、盐碱特征之间的相关性。结果表明:(1)6种典型盐生景观中农田土壤分形维数值最小(2.35),碱蓬群落土壤最大(2.61),分形维数均值为2.48,分形维数随盐生景观土壤碱化程度增加而增大。(2)土壤质地越粗,砂粒含量越高,分形维数值越小;土壤质地越细,黏粒和粉粒含量越高,分形维数越大。(3)分形维数与盐分含量呈显著正相关(r=0.87,P0.05),尤其与盐分组成中HCO_3~-含量呈极显著正相关(r=0.89,P0.01),与养分中总磷含量呈极显著正相关(r=0.90,P0.01)。(4)土壤颗粒组成中砂粒、粉粒和黏粒与盐分、HCO_3~-及总磷含量也存在极显著相关性。不同盐生景观土壤分形维数与土壤颗粒组成和土壤盐分之间存在显著的相关性,因此可以用分形维数来反映土壤质地和指示土壤盐碱化特征。

Fractal Dimension and Salinization Characteristics of Typical Halophytic Landscape Soil in Western Songnen Plain

The objective of this study was to explore the correlation between characteristics of fractal dimension and soil texture and alkalinity of typical halophytic landscape in the Western Songnen Plain, China. A volume-based fractal model was adopted to calculate the particle-size composition and fractal dimension of the 0-30 cm soil of six typical halophytic landscapes, and the relationships among soil fractal dimension and texture, alkalinity characteristics were analyzed by correlation analysis. The results showed that:(1) Among the six typical halophytic landscapes, the fractal dimension of farmland soil was the smallest (2.35), and that of Artemisia suaeda community soil was the largest (2.61), and the average fractal dimension was 2.48. The fractal dimension increased with the increasing of alkalization degree of halophytic landscape soil. (2) The coarser the soil texture was, the higher the sand content was, and the smaller the fractal dimension value was. The finer the soil texture was, the higher the content of clay and silt was, and the larger the fractal dimension was. (3) Fractal dimension was significantly positively correlated with salt content (r=0.87, P<0.05), especially with HCO₃^- content in salt composition (r=0.89, P<0.01) and total phosphorus content in nutrients (r=0.90, P<0.01). (4) There were also significant correlations among particle-size composition, salt content, HCO₃^- content and total phosphorus. The fractal dimension of different halophytic landscape soils were significantly correlated with soil particle size composition and soil salinity, so the fractal dimensions could be used to reflect soil texture and indicate soil salinization features.