大气氮沉降对森林土壤酸化的影响

EFFECTS OF ATMOSPHERIC NITROGEN DEPOSITION ON FOREST SOIL ACIDIFICATION

因大气污染而不断增加的大气氮沉降量 ,在许多地区超过了森林生态系统的氮需求。氮在土壤中的化学和生物化学反应对H+ 离子的产生与消耗有重要影响。NH+4和NO-3输入与输出的平衡状态影响着土壤 -土壤溶液系统的酸化速率。过剩的氮沉降将增加NH+4的硝化和NO-3的淋失 ,加速土壤的酸化。土壤酸化对森林有危害作用。

The increased deposition of atmospheric nitrogen due to the air pollution has exceeded the demands of forest ecosystems in many areas.The chemical and biochemical reactions of nitrogen in soils have significant effects on the production and consumption of H+.The balance between the inputs and outputs of NH+ 4 and NO- 3 determines the rate of acidification of the soil-soil solution system. Excessive nitrogen deposition will enhance the nitrification of NH+ 4 and the leaching of NO- 3,which are the processes of strong acidification.An increase in the NO- 3 concentration will increase the acidity and aluminium concentration in the soil solution.Basic cations will be leached out for accompanying the NO- 3 leaching,resulting in the acceleration of soil acidification.Soil acidification is harmful to forest.