Variations of (superscript 15)N Natural Abundance in Leaves and Soils of Two Natural Lauro-Fagaceae Forests in Taiwan

臺灣兩個天然楠櫟林葉片與土壤(上標 15)N天然豐富度之變異

王巧萍(Chiao-Ping Wang) ； 林國銓(Kuo-Chuan Lin)

《台灣林業科學》 18卷2期 (2003/06) Pp. 153-158

https://doi.org/10.7075/TJFS.200306.0153

摘要

本研究測定福山與六龜兩個天然楠櫟林葉片與土壤(上標 15)N天然豐富度之變異，以瞭解亞熱帶森林之氮循環與氮利用效率之趨勢。福山土壤之氮濃度(0.67±0.11%)雖明顯低於六龜(1.19±0.05%)，但兩試驗地之葉片平均氮濃度（福山：1.19±0.18%。六龜：1.88±0.32%）則無顯差異。福山之葉片與土壤(上標 15)N天然豐富度分別爲-1.9±1.3及1.6±0.5‰，這可能是由於福山之高降雨量，使得在礦化過程中因同位素分離作用而較輕的硝酸根可大量淋溶流失，而留下較重的(上標 15)N所致。本研究中的兩亞熱帶天然楠櫟林葉片與土壤之平均(上標 15)N天然豐富度之測值，均明顯較熱帶森林爲低，而與溫帶林者相似。

關鍵字

穩定同位素 ； (上標 15)N天然豐富度 ； 亞熱帶土壤 ； 楠櫟林

並列摘要

Foliar and soil δ (superscript 15)N values of 2 subtroical Lauro-Fagaceae forests of Fushan and Liukuei, Taiwan, were investigated to understand N cycling and N use efficiency trends. Although the soils from Fushan(0.67±0.11%) contained less nitrogen than those from Liukuei(1.19±0.05%), there was no significant difference between the average nitrogen contents in foliage (Fushan 1.91±0.18%, Liukuei 1.88±0.32%). The average foliar and soil δ (superscript 15)N values of Fushan (-1.9±1.3 and 1.6±0.5‰) were both significantly higher than those of Liukuei(-4.4±1.0 and 0.6±0.1‰). This may be due to the higher precipitation at Fushan which could lead to more N losses through leaching of nitrate derived from nitrification and leave the heavier (superscript 15)N remaining in the system The δ (superscript 15)N values of subtropical foliage and soils measured in this study were significantly lower than those reported from tropical forests; however, they did not significantly differ from those of temperate forests.

並列關鍵字

stable isotope ； δ (superscript 15)N ； subtropical soils ； Lauro-Fagaceae forest