The Preferential Flow Feature Of Main Forest Types And The Factors Of The Preferential Flow In Fengyang Mountain

Because preferential flow play a important role in water conservation,ground water pollution,the loss of soil nutrients and geological disaster. More and more people begin to pay attention to the study of preferential.Pore structure in soil,soil organic matter content,the fractal dimension of soil aggregate,root density,the surface area of root,the volume of root,the number of root tips,the number of root forks,the quality of rocks,the surface area of rocks are on the occurrence of preferential flow.To characterize the influence of plant roots,rock fragment and soil characteristic on soil preferential flow,Fengyang mounter in Zhejiang province was studied so as to explore the relationship between them.(1)0cm~60cm soil depth,root length density of root system whose diameter<0.6mm,0.6mm~1.2mm,1.2mm~1.8mmand>1.8mm is decreasing with the increasing depth.(2)The capillary porosity,non capillary porosity,total porosity and the soil organic matter content decreasing with the increasing of soil depth.The number of soil aggregate is decreasing with the increase of soil depth.(3)The root length density diameter>0.6mm root system was higher in preferential flow region compared with it in soil matrix region within the same and depth. So was the surface area,volume,tips and forks of root,the quality and surface area of rock,non-capillary porosity.(4) By principal component analysis, the main factors affecting the preferential flow path are root length density of diameter > 0.6mm root system,the surface area,volume,tips and forks of root,the quality and surface area of rock,non-capillary porosity. By calculating the principal component score of preferential flow area and the matrix flow area in 36 micro-regions, results showed that the composite score in 27 plots were greater in preferential flow region than it in matrix flow area,accounting for 75% of the total micro-regions,indicating that the five factors mentioned above are also the main factors influencing the preferential flow paths by the principal component analysis.Soil organic matter can accelerate the transfer of preferential flow velocity.