关键词: 棉田, 除草剂, 节肢动物群落, 多样性指数

Abstract: By the method of litterfall trap, and from May 2003 to September 2004, an investigation was made on the dynamic charcteristics of the litterfalls in four typical forests along a vertical vegetation zone on the north slope of Changbai Mountains. In the meanwhile, the annual nutrient return of the litterfalls was calculated through nutrient content anlysis. The results showed that different forest types in Changbai Mountains had differnt litter-falling rhythm and different litter composition. Though the seasonal pattern of the litter-falling rhythm was of one-peak, the peak values for the forests appeared at different periods of time. The annual litter-falling amount and the litter composition differed obviously among different forest types and among different periods of time in the same forest type. Broadleaved Korean pine forest had the largest annual litter-falling amount (about 490 g·m^-2), followed by Korean pine-spruce fir forest, Betula ermanii-spruce fir forest, and B. ermanii forest. There was a significant negative correlation between annual litter-falling amount and altitude. The amount of nutrient return from the litterfalls in the four forests was C>ash>N>K>P, and the total amount of the nutrient return was decreased with increasing altitude.

Key words: Cotton field, Herbicide, Arthropod community, Diversity index