Abstract:

The condition of soil structure is an important factor to affect soil fertility.The soil heterogeneity,which embodies the landscape heterogeneity,has an important role in revealing the form mechanism,function and variation of landscape.In this paper,the soil physical property heterogeneities of six types of forest landscape in Wuyishan scenery district include Pinus massoniana forest, Cunninghamia lanceolata forest,economic forest,bamboo forest,broad leaved forest and Camellia sinensis plantation were analyzed,and the fractal model was used to study the soil aggregate structure.The results showed that the soil physical property heterogeneities of different forest landscapes were distinct.The stand structure of three natural forests( Pinus massoniana forest, Cunninghamia lanceolata forest and broad leaved forest)were more complex than that of three artificial forests(economic forest,bamboo forest and Camellia sinensis plantation),thus,their fractal dimensions of soil aggregate were lower,the contents of the particle > 0.25 mm aggregate and > 5 mm aggregate were higher,the capacity of stable aggregate composition under water and permeability of soil were more splendid,the performance of self-regulation and resistance were better,and the non-capillary pore of soil were more flourishing than artificial forests. The regression models for fractal dimension (D)of aggregated structure and water stable aggregate(>0.25 mm and >5 mm)content,and for D and destroyed structure percentage were further established,and the results indicated the their regression relationships of all the models were remarkable,therefore,the fractal dimension of soil structure could be used as an index in characterizing the soil fertility.

Key words: Wuyishan scenery district, forest landscape, soil, heterogeneity, fractal dimension