关 键 字(英文)：Coniferous and broad-leaved mixed forest Hydrology Total organic carbon （TOC）
摘 要(英文)：The total flux and concentration of total organic carbon ( TOC) in hydrological processes in coniferous and broad2
leaved mixed forest of Dinghushan were measured from J uly 2002 to J uly 20031The results showed that the TOC
input by precipitation was 41180 kg·hm- 2·yr - 1 ,while its output by surface runoff and groundwater (soil solu2
tion at 50 cm depth) was 17154 and 1180 kg·hm- 2·yr - 1 ,respectively. The difference between input and output
was 22146 kg·hm- 2·yr - 1 ,indicating that the ecosystem TOC was in positive balance. The monthly variation of
TOC flux in hydrological processes was very similar to that in precipitation. The mean TOC concentration in pre2
cipitation was 3164 mg·L - 1 ,while that in throughfall and stemflow increased 6110 and 7139 times after rain
passed through the tree canopies and barks. The mean TOC concentration in surface runoff and in soil solution at
25 and 50 cm depths was 12172 ,71905 and 3106 mg·L - 1 , respectively. The monthly TOC concentration in
throughfall and stemflow had a similar changing tendency ,showing an increase at the beginning of growth season
(March) ,a decrease after September ,and a little increase in December. The TOC concentration in runoff was
much higher during high precipitation months. No obvious monthly variation was observed in soil solution TOC
concentration (25 and 50 cm below the surface) . Stemflow TOC concentration differed greatly between different
tree species. The TOC concentration in precipitation ,throughfall ,and soil solution (25 and 50 cm depths) de2
creased with increasing precipitation ,and no significant relationship existed between the TOC concentrations in
stemflow ,surface runoff and precipitation. The TOC concentrations in the hydrological processes fluctuated with
precipitation intensity ,except for that in stemflow and soil solutions.
鼎湖山针阔叶混交林水文学过程中总有机碳动态