关键词: 台湾桤木, 四川桤木, 细根, 抗蚀性

Abstract: A study was carried out on the distribution character of biomass of fine root (≤1mm) in two different forest lands (Alnus formosana-Lolium multiflorum forest land),mode Ⅰ and Alnus formosana-Natural grass forest land (mode Ⅱ),in contrast with Alnus cremastogyme-Natural grass forest land (mode Ⅲ).The principal component analysis (PCA) was used to study the influential factors of soil anti-erodibility in the three types of forest lands.The results showed that the biomass of fine root (≤1mm) in different layers are different in the following descending sequence: upper layer,middle layer,lower layer,and at an approximate ratio: 44∶30∶26 (modeⅠ),51∶34∶15 (mode Ⅱ),49∶33∶18 (mode Ⅲ).The annual average biomass of fine root in mode Ⅰ forest land is 1.5 times that of another two forest lands.PCA comprehensive exponent of anti-erodibility influential factors showed that the order of anti-erodibility: mode Ⅰ (0.798) > mode Ⅱ (-0.383) > mode Ⅲ (-0.399),and that the anti-erodibility of soil in three types of forest lands is in decreasing trend from topsoil to bottom soil.

Key words: Alnus formosana, Alnus cremastogyme, fine root, anti-erodibility