| 【Objective】The study probed into the fractal characteristics and particle size distribution of soil in
the meadow wetland of Yinchuan Plain and their variation in vertical profile of soil, and made a preliminary exploration on
the relationship between the fractal dimension of soil and the diversity of plant communities in the study area.【Method】
Taking the soil of meadow wetland in Yinchuan Plain as the research object, the study area was divided into three habitats,
i.e. low humidity meadow, typical meadow and halophytic meadow based on the differences of water and salinity..Fractal
characteristics of soil were characterized by particle size distribution. Simpson species dominance index, Shannon-Weiner
species diversity index, Margalef species richness index and Pielou species evenness index were selected as plant diversity
indexes, and a comparative study was carried out. 【Result】The soil of meadow wetland in Yinchuan Plain was dominated by clay micro-aggregates, and the fractal dimension values ranged from 2.28 to 2.84. There were significant differences in soil
fractal dimensions of three types of meadow wetlands, and the fractal dimension values were showed as: typical meadow (2.74)
> halophytic meadow (2.72) > low humidity meadow (2.66). The fractal dimension of soil was positively correlated with clay
content and negatively correlated with the content of ultra-fine sand and fine sand. The contents of surface clay and silt were
relatively high in the vertical profile of soil while the contents of ultra-fine sand and fine sand were higher in deep layer. The
content of medium sand fluctuated greatly, and the coarse sand only appeared in the surface layer or deep layer. The species
diversity of plant communities in low humidity meadow was higher and the average diversity index was 1.15.【Conclusion】
Soil particle size and fractal characteristics of meadow wetlands in Yinchuan Plain were obviously affected by the hydrological
relation of local topography environment. Soil and water processes had a direct impact on species diversity of plant communities.
Soil physical structure played an indirect driving role in species diversity of plant communities, and human factors played a vital
role at the same time. |
