中国南部亚热带森林流域主要化学成分的输入量和输出量

INPUTS AND OUTPUTS OF MAJOR CHEMICALS IN A SUBTROPICAL FORESTED WATERSHED IN SOUHTERN CHINA

对中国南部一个常绿阔叶林的溶质输入量、输出量和积存量进行了评价。输入量和输出量随季节而变化,并与水量的变化密切相关。春季至初夏水量增大,溶质的输出量,特别是盐基阳离子,HCO_3^-和 Si 也随之增加。积累于流域中的硫(723eq/hm^2·a)可能是来源于中国西南部城市和工业区的大气污染。由于内部循环,氮主要保存于土壤中(409eq/hm^2·a)。钾的损失受到内部循环的抑制。钠在生态系中则保持不强。镁在植被中的含量很高,但由风化的产出量也多。大气的钙输人量导致高的钙输出量。

Solute input and output budgets were evaluated for an evergreen broad-leaved forest in sothern China.Inputs and outputs varied with season,and were linked to water flux patterns.During spring to early summer with high water flow,solute output increased especially for base cations,HCO_3^-,and Si. The sulfur that accumulated in the watershed(723 eq/ha/y)were probably derived from atmospheric sources in the urban and industrial areas in the southwestern part of Chia.Considering internal cycling, nitrogen was highly retained in the soil(409 eq/ha/y).Loss of K was inhibited by internal cycling.Sodi- um was not held tightly in this ecosystem.For Mg,content in vegetation was high,but production by weathering was also important.Atmospheric Ca input contribute to higher output of Ca.