Effects of atmospheric nitrogen deposition on nutrient balances in forest ecosystems

大气氮沉降对森林生态系统养分平衡的影响

基本信息

批准号：
11680533
负责人：
BABA Mitsuhisa
金额：
$ 2.3万
依托单位：
Kitasato University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11680533/
关键词：
Acidic deposition Ammonium ion Base cations decomposition of litter Forest ecosystem Japanese cedar stands Nitrogen saturation Uptake of nitrogen

项目摘要

Nitrogen deposition exceeded 10 kg N ha^<-1> yr^<-1> at Shichinohe in Aomori. Nevertheless, there were no symptoms of nitrogen saturation. The aim of this study was to examine the effects of atmospheric deposition on nitrogen dynamics and budget of other elements in Japanese cedar (Cryptomeria japonica) stands.Ammonium input owing to open bulk precipitation increased in summer when wind blew from southeast or south. Uptake of nitrogen in the canopy increased in summer. This suggests that Japanese cedar stands are deficient in nitrogen and atmospheric nitrogen deposition is therefore likely to increase forest growth.Production of acidity due to nitrogen transformation affected on the total acid production in soil profile. Produced acidity was consumed by cation exchange and/or weathering. Calcium ion supply from litter layer exceeded leaching from the depth of 10 cm. Japanese cedar needle contained large amounts of calcium contributed to supply and accumulation of calcium ion. Therefore, it was concluded that serious soil acidification scarely arise in this Japanese cedar stands. In addition, base cations were accumulated in litter layers when litter decomposition rate was low. Incase of high decomposition rate, base cations were accumulated in soil profile. Litter layer affected not only on base cation accumulation, but also on percolated water amounts. Physical properties of litter layer are important to estimate nutrient budget in forest ecosystems.

青森县七户市的氮沉降量超过10kg N ha^-1 yr^-1。然而，没有出现氮饱和的症状。本研究的目的是研究大气沉降对日本柳杉（Cryptomeria japonica）林中氮动态和其他元素预算的影响。夏季，当风从东南或南面吹来时，由于露天大量降水导致铵输入增加。夏季冠层对氮的吸收增加。这表明日本雪松林缺乏氮，因此大气中的氮沉降可能会促进森林生长。氮转化产生的酸度影响土壤剖面中的总酸产量。产生的酸度通过阳离子交换和/或风化而消耗。凋落物层的钙离子供应超过了10厘米深度的淋滤量。日本柳杉针含有大量的钙，有助于钙离子的供给和积累。因此，可以得出结论，该柳杉林中几乎不会发生严重的土壤酸化。此外，当凋落物分解率较低时，碱金属阳离子会在凋落物层中积累。在高分解率的情况下，碱性阳离子在土壤剖面中积累。凋落物层不仅影响碱阳离子积累，而且影响渗滤水量。凋落物层的物理特性对于估计森林生态系统的养分预算很重要。