Abstract: Field replanting bioassay was conducted on the soils having planted wi th Rehmannia glutinosa for 2, 4, 6, and 8 years. The soils were repl anted with R. glutinosa, and 5 phenolic acids (coumalic acid, 4-hydroxybenz oic acid, venillic acid, syringic acid and ferulic acid) closed related to allel opathetic effects in the replanted soils were analyzed by using high pressure li quid chromatography (HPLC). The results showed that on the soils with increasing planting interval years of R. glutinosa, the root tube dry mass and volume and the leaf dry mass of replanted R. glutinosa increased since seeding stag e then, while the contents of test five phenolic acids in the replanted soils de creased accordingly. The total contents of test five monohydric phenolic acids i n the replanted soils having been planted with R. glutinosa for 2, 4, 6, and 8 years was 1503, 1323, 0700, and 0340 μg·g-1, respectively, an d the content of ferulic acid, 4-hydroxybenzoic acid, and coumalic acid in soil water extract had significant negative correlation with filed planting bioassay results. As a whole, the early and middle growth stages of R. glutinosa sho uld be the crucial periods for the allelopathetic effects of R. glutinous.

Key words: Litterfall, Forest type, Litter components, Litter dynamics