Seasonal changes of nitrate concentrations in baseflow headwaters of coniferous forests in Japan: A significant indicator for N saturation

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• 作者：Zhao Zhang ; Takehiko Fukushima ; Peijun Shi ; Fulu Tao ; Yuichi Onda ; Takashi Gomi ; Shigeru Mizugaki ; Yuko Asano ; Ken'ichirou Kosugi ; Shinya Hiramatsu ; Hikaru Kitahara ; Koichiro Kuraji ; Tomomi Terajima
• 关键词：Baseflow ; Coniferous forest ; Headwater ; Nitrogen ; N saturation indicator ; Watershed
• 刊名：Catena
• 出版年：2008
• 出版时间：15 December 2008
• 年：2008
• 卷：76
• 期：1
• 页码：63-69
• 全文大小：1060 K

文摘

Understanding the seasonal and regional patterns of nitrogen (N) components in the headwaters of forested watersheds is important for forests management. Here, we investigated the NO₃-N concentration and its seasonal variations in the baseflow headwaters in Japanese coniferous forests with different N saturation status in five regions (i.e., Nagano, Tokyo, Aichi, Kochi and Mie). We found that the ratios of NO₃-N to DON were significantly higher in the N-saturated regions including Nagano (14.1 ± 2.2) and Tokyo (16.5 ± 4.1), compared with the regions, which didn't experience N saturation including Aichi (1.4 ± 0.2), Kochi (5.1 ± 1.8), and Mie (2.2 ± 0.5). In comparison with the regions without experiencing N saturation, the relatively higher NO₃-N concentration, as well as its contrastive variation between growing season and dormant season, was also characteristic of the seasonal NO₃-N concentration in the N-saturated regions. Our findings have indicated that NO₃-N concentration, its seasonal variations, and the ratio of NO₃-N to DON, are the better and applicable indicators for evaluating N saturation status in Japanese coniferous forests.