N isotopes and N cycle in the TieShanPing subtropical forest ecosystem, Southwestern China
N isotopes and N cycle in the TieShanPing subtropical forest ecosystem, Southwestern China
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DOI：
10.1007/s10661-008-0398-z
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发表时间：
2009-07
影响因子：
3
通讯作者：
Chunqian Jiang;Xiaoshuai Zhang
中科院分区：
文献类型：
--
作者：
Chunqian Jiang;Xiaoshuai Zhang
氮对森林生长和林分发育至关重要。它通常是森林生产力的一个有限因素。通过研究植被对N的利用来源和N的循环，研究了43年历史的马尾松（Pinus massoniana）森林生态系统中土壤和植物的δ 15n值。植物材料的N浓度在1.1% ~ 2.2%之间。p的氮浓度。马尾草浓度为1.3%，土壤浓度为0.04 ~ 0.15%。在15n自然丰度方面，灌木和乔木叶片的δ 15n值变化较大（−6.0‰~−3.8‰）。人工林先驱种的δ15N值也在−4.7‰~−3.8‰之间变化显著。与植物样品相比，土壤δ 15n值（3.1 ~ 6.3‰）显著增加。尽管植被覆盖的δ 15n值为负，但表层土壤的高δ 15n值表明，铁山坪上的凋落物对土壤的氮返还很少，目前的森林对表层土壤15n信号的改变不大。正的δ 15n值也可能表明土壤系统的淋滤、挥发和植物吸收造成了大量的氮损失。
Nitrogen is essential for forest growth and forest stand development. It is commonly a limited factor for forest productivity. We examinedδ15N values in soils and plants by studying the sources of N used by vegetation and cycles of N in a 43-year-old plantation of the TieShanPing forest ecosystem in southwestern China, dominated by massone pine (Pinus massoniana). The N concentration of plant materials ranges from 1.1% to 2.2%. The nitrogen concentration ofP. massonianawas 1.3% while soils showed the concentration of 0.04–0.15%. Regarding natural abundance of15N, large significant variation (−6.0‰ to −3.8‰) inδ15N values was observed among shrub and tree leaves.δ15N values were also significantly varied from −4.7‰ to −3.8‰ among the pioneer species in the plantation. Soilδ15N values (3.1–6.3‰) were significantly enriched compared to those values in plant samples. Despite the negativeδ15N values of the vegetation cover, the highδ15N values in the topsoil indicate that return of N to soils by litter-fall is minimal on TieShanPing and the present forests do not change very much the soil15N signals at the surface layer. The positiveδ15N values may also indicate large N losses from the soil system vial leaching, volatilization and plant uptake.