Study on weathering that alleviate soil acidification due to atmospheric nitrogen deposition

风化作用缓解大气氮沉降土壤酸化的研究

基本信息

批准号：
18580063
负责人：
BABA Mitsuhisa
金额：
$ 2.51万
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：
2006
资助国家：
日本
起止时间：
2006 至 2007
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-18580063/
关键词：
Weathering Silica Nitrogen deposition Strontium isotope Calcium O horizon(Litter layer)Amount of acid production O層(堆積腐植層)

项目摘要

Atmospheric nitrogen deposition causes soil acidification but soils have various acid buffer reactions. We aimed to examine contribution of weathering and supplies of base cations owing to litter decomposition based on changes in nitrogen dynamics, acid production, and buffering reaction due to reaping understory vegetation under Japanese cedar (Cryptomeria japonica). Reaping understory vegetation decreased in uptake of nitrogen and water. Increase in soil temperature owing to reaping (about 2℃ higher in reaping area than in un-reaping area) affected on activities of mineralization of organic nitrogen and subsequent nitrification. This was also a cause of increases in nitrogen leaching. In addition, increase in supplies of dissolved organic carbon from 0 horizon(Litter layer)due to increase in soil temperature also affected on activities of mineralization and nitrification.Increases in nitrogen leaching made increase in acid production due to nitrogen transformation. This acid production had the highest correlation coefficient between silica mobilization and its explanatory factors. Strontium isotope ratio (^<87>Sr /^<86>Sr) was negatively proportional to silica concentration. Since minerals have lower^<87>Sr/^<86> Sr, compared rainfall and plants or soils, weathering should contribute to acid buffering reaction. We also analyzed^<87>Sr/^<86>Sr of extracts, which analysis for total and exchangeable calcium (Ca) contents in O horizon. The ratio increased from Oi horizon (not decomposed litters) to Oe horizon (humified litters). It suggested that increase in exchangeable Ca in litter accompanied with decrease in litter weight would be ascribed to not only transformation from non-exchangeable form but to Ca in rainfall. Since supplies of calcium from 0 horizon alleviate soil acidification, we should try to examine relationship between weathering and supplies of Ca.

大气氮沉降导致土壤酸化，但土壤有各种酸缓冲反应，我们的目的是根据日本收获林下植被导致的氮动力学、酸产生和缓冲反应的变化，研究由于凋落物分解而导致的风化和碱阳离子供应的贡献。雪松（Cryptomeria japonica）因收割而导致林下植被吸收氮和水的量减少（收割区土壤温度比收割地高约2℃）。未收割区）影响了有机氮的矿化和随后的硝化作用，这也是氮淋滤增加的原因。此外，由于土壤的增加，来自0层（凋落物层）的溶解有机碳的供应增加。温度也影响矿化和硝化活性。氮浸出的增加导致由于氮转化而产生的酸产量增加，这种酸产量在二氧化硅动员与其解释因素之间具有最高的相关系数。同位素比(^ 87 Sr /^ 86 Sr)与二氧化硅浓度成负比，因为矿物具有较低的^ 87 Sr/^ 86 Sr，与降雨和植物或土壤相比，风化应该有助于酸性。我们还分析了提取物的^<87>Sr/^<86>Sr，其分析了O层中的总钙(Ca)含量和可交换钙(Ca)含量，该比率从Oi层中增加。这表明，随着凋落物重量的减少，凋落物中可交换钙的增加不仅归因于不可交换形式的转变，而且归因于降雨中钙的供应。为了缓解土壤酸化，我们应该尝试考察风化作用与钙供给之间的关系。