Comparison of soil carbon stocks in Scottish soils between 1978 and 2009
Comparison of soil carbon stocks in Scottish soils between 1978 and 2009
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DOI：
10.1111/ejss.12041
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发表时间：
2013-08-01
影响因子：
4.2
通讯作者：
Towers, W.
中科院分区：
文献类型：
--
作者：
Chapman, S. J.;Bell, J. S.;Towers, W.
在苏格兰20公里网格上的179个地点测量了19-31年（平均25年）土壤碳(C)储量的变化。采样是在一个侧面坑中按水平进行的。虽然在第一次采样时没有土壤容重测定，但我们使用了第二次采样时的容重值，根据近红外光谱校准来预测缺失的值。土壤总碳储量（平均+/-标准误差，深度为100cm）没有可检测到的变化，第一次和第二次采样分别为266 +/- 15和270 +/- 15tCha(-1)，或特定植被或土壤类型的总体碳储量。例外是在林地的土壤,排除那些深泥炭,表现出显著(P = 0.05)增益为1.0 tcha(1)(1)。林地（主要是针叶林）土壤C含量显著（P=0.04）增加（gkg(-1)），容重显著降低（P=0.006），凋落物-发酵-腐殖质（LFH）层厚度显著增加（P=0.06）。重新计算深度为15cm的碳储量表明，总体碳储量显著增加（排除深层泥炭地），特别是在沼地和林地土壤中，这表明如果我们只采样到15cm，我们会得出不同的结论。改良后的草地土壤和初步耕作后的草地土壤C含量均显著降低。Ap层的平均厚度从29 cm增加到32cm， C含量降低，容重略有增加；我们将此归因于采样时期之间更深层次的耕作。在可能的土壤C损失的情况下，我们可以95%地相信平均损失不超过0.2%(-1)，99%地相信它不超过0.4%（-1）。
The change in soil carbon (C) stock over a 19-31-year period (mean 25years) has been measured at 179 sites on a 20-km grid across Scotland. Sampling was by horizon from a profile pit. Although soil bulk density determinations were absent at the first sampling time, we used bulk density values from the second sampling time calibrated against NIR spectra to predict the missing values. There was no detectable change in overall total soil C stock (mean +/- standard error, to a depth of 100cm), which was 266 +/- 15 and 270 +/- 15tCha(-1) for the first and second sampling times, respectively, or generally in C stock within specific vegetation or soil types. The exception was for soils under woodland, excluding those on deep peat, which exhibited a significant (P=0.05) gain of 1.0tCha(-1)year(-1). Soils under woodland (mainly coniferous plantation) also showed a significant (P=0.04) increase in C content (gkg(-1)), a significant decrease in bulk density (P=0.006) and an increase in the thickness of the Litter-Fermentation-Humus (LFH) layer (P=0.06). Recalculating the C stock to a depth of 15cm showed a significant increase in overall C stock (when deep peat sites were excluded) as well as specifically in moorland and woodland soils, suggesting that had we sampled only to 15cm, we would have reached a different conclusion. Both improved grassland soils and those initially under arable cultivation showed a significant decrease in C content. However, the mean thickness of Ap horizons increased from 29 to 32cm, with a concomitant decrease in C content and a slight increase in bulk density; this we ascribe to deeper ploughing between the sample periods. In the context of possible soil C losses, we can be 95% confident that the mean loss does not exceed 0.2%year(-1) and 99% confident that it does not exceed 0.4%year(-1).