Impact of long-term nitrogen addition on carbon stocks in trees and soils in northern Europe
Impact of long-term nitrogen addition on carbon stocks in trees and soils in northern Europe
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DOI：
10.1007/s10533-007-9121-3
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发表时间：
2008-05-01
期刊：
影响因子：
4
通讯作者：
Linder, Sune
中科院分区：
文献类型：
--
作者：
Hyvonen, Riitta;Persson, Tryggve;Linder, Sune
本研究的目的是通过分析在瑞典和芬兰的云杉（Picea abies）和西尔松（Pinus sylvestris）林分进行的15个长期（14-30年）试验数据，量化肥料N对树木（茎、桩、枝、针和粗根）和土壤（有机层+0-10 cm矿物土）中碳储量的影响。低施氮量（30-50 kg N ha（-1）年）比高施氮量（50-200 kg N ha（-1）年（-1））的单位氮效率更高。累积施氮量为600 ~ 1800 kg N ha（-1）可使树木和土壤碳储量平均分别增加25和11 kg（固碳）kg(-1)（添加氮）（“氮利用效率”）。相应的氮磷钾添加量估计分别为38和11 kg(C) kg(-1) (N)。树木固碳的氮素利用效率与土壤氮素状况密切相关，腐殖质层在C/N 25时接近于零，在C/N 35时增加到40 kg(C) kg(-1) (N)，在C/N 50时又下降到20 kg(C) kg(-1) (N)左右。相反，氮磷钾在富氮（C/N 25）位点的氮素利用效率也较高(40-50 kg(C) kg（-1) (N)）。富氮区施氮磷钾和施氮肥在氮利用效率上的巨大差异反映了富氮区树木生长的磷和钾限制。土壤有机碳（SOC）固存的氮利用效率平均比树木碳固存低3-4倍。然而，冷杉地的固碳量约为杉木地的两倍，平均分别为13和7 kg(C) kg(-1) (N)。利用N利用效率与腐殖质C/N比值之间的强相关性来评价N沉降对碳固存的影响。数据表明，在一个世纪的时间里，瑞典南部比瑞典北部多10 kg N ha（-1）年（-1）的沉积，导致南方冷杉样地的树C比北方多2.0 +/- 1.0（95%置信区间）kg m(-2)， SOC比北方多1.3 +/- 0.5 kg m（-2）。这些估算结果与其他研究发现的南方和北方在树碳和有机碳方面的差异是一致的，70-80%的有机碳差异可以用不同的N沉降来解释。
The aim of this study was to quantify the effects of fertiliser N on C stocks in trees (stems, stumps, branches, needles, and coarse roots) and soils (organic layer +0-10 cm mineral soil) by analysing data from 15 long-term (14-30 years) experiments in Picea abies and Pinus sylvestris stands in Sweden and Finland. Low application rates (30-50 kg N ha(-1) year(-1)) were always more efficient per unit of N than high application rates (50-200 kg N ha(-1) year(-1)). Addition of a cumulative amount of N of 600-1800 kg N ha(-1) resulted in a mean increase in tree and soil C stock of 25 and 11 kg (C sequestered) kg(-1) (N added) ("N-use efficiency"), respectively. The corresponding estimates for NPK addition were 38 and 11 kg (C) kg(-1) (N). N-use efficiency for C sequestration in trees strongly depended on soil N status and increased from close to zero at C/N 25 in the humus layer up to 40 kg (C) kg(-1) (N) at C/N 35 and decreased again to about 20 kg (C) kg(-1) (N) at C/N 50 when N only was added. In contrast, addition of NPK resulted in high (40-50 kg (C) kg(-1) (N)) N-use efficiency also at N-rich (C/N 25) sites. The great difference in N-use efficiency between addition of NPK and N at N-rich sites reflects a limitation of P and K for tree growth at these sites. N-use efficiency for soil organic carbon (SOC) sequestration was, on average, 3-4 times lower than for tree C sequestration. However, SOC sequestration was about twice as high at P. abies as at P. sylvestris sites and averaged 13 and 7 kg (C) kg(-1) (N), respectively. The strong relation between N-use efficiency and humus C/N ratio was used to evaluate the impact of N deposition on C sequestration. The data imply that the 10 kg N ha(-1) year(-1) higher deposition in southern Sweden than in northern Sweden for a whole century should have resulted in 2.0 +/- 1.0 (95% confidence interval) kg m(-2) more tree C and 1.3 +/- 0.5 kg m(-2) more SOC at P. abies sites in the south than in the north for a 100-year period. These estimates are consistent with differences between south and north in tree C and SOC found by other studies, and 70-80% of the difference in SOC can be explained by different N deposition.