Abstract: By the method of in situ litterfall lessening, the litterfall decompos ition in four forest types (broadleaf-Korean pine forest, Korean pine and spruc e-fir mixed forest, Betula ermanii and spruce-fir mixed forest, and B. e rmanii forest) on the north slope of Changbai Mountains Nature Reserve was stu died from May 2003 to September 2004. The results showed that Korean pine and sp ruce-fir mixed forest had the largest quantity of standing litterfall, followed by broadleaf-Korean pine forest, B. ermanii and spruce-fir mixed forest, and B. ermanii forest. There existed an exponential relationship between lit terfall decomposition rate and time. The annual decomposition rate of the litter fall in different forest types ranged from 25% to 47%, being the largest in broa dleaf-Korean pine forest, followed by in B. ermanii forest, Korean pine and spruce-fir mixed forest, and B. ermanii and spruce-fir mixed forest, and the time for decomposing 95% of the litterfall took about 18 to 39 years. In the same forest types, the annual decomposition rate of different plant components diff ered obviously, generally with broad leaf being the largest and conifer being th e least.

Key words: Oryza sativa, Allelopathy, Agronomic character, Weed-inhibiting effect, Variety