Chemical composition of rainfall, throughfall, runoff and outlet flow in a small watershed of secondary forest, eastern China

摘要

Rainfall, throughfall, stemflow, runoff and outlet flow were studied in a secondary forest during a rain season from April to October in 2009. Some of the chemicals in throughfall, stemflow, runoff and outlet flow were increased in contrast with incident rainfall. The pH value of the water sample was in the order rainfall > throughfall > runoff > outlet flow > stemflow. The concentration of chemicals of rainfall was in the order (SO_4)~(2-) > (NO_3)~- > Na~+> Cl~- > K~+> Ca~(2+)> (NH_4)~+> Mg~(2+)>(PO_4)~(3-) The mean concentrations of nutrients in throughfall, stemflow and runoff were significantly higher than those in incident rainfall except Na~+ and (NH_4)~+. The concentration of chemicals of outlet flow was in the order (SO_4)~(2-) > Cl~- > (NO_3)~-> Ca~(2+)> Mg~(2+) > Na~+> K~+>(NH_4)~+ >(PO_4)~(3-) .