ABSTRACT Most peatlands in Indonesia border mineral upland, yet research reporting the effects of the presence of mineral upland on the distribution of mineral nutrients are limited. We collected multiple samples in surface layers from a peatland located between the Siak River and a mineral upland in Riau Province, Indonesia and measured electrical conductivity, pH, and exchangeable Ca2+, Mg2+, K+, and Na+. Transects were investigated for ash content and chemical composition of its profiles. Although electrical conductivity (183 ± 79 μS cm–1) and pH values (3.7 ± 0.3) were similar at surface layers, exchangeable Ca2+ (especially near the mineral upland) and Mg2+ were high at 0–15 cm deep (8.3 ± 5.1 cmolc kg–1 and 2.7 ± 1.1 cmolc kg–1, respectively) and tended to decline in the lower layers. Exchangeable K+ and Na+ did not show a clear trend, probably because of weaker bonding with peat material. High ash content (>10%) was found more frequently alongside the mineral upland than by the riverbank. In the profiles near the mineral upland, total Ca, Mg, Al, and Fe levels in the surface layer were higher (4.5 ± 0.3 g kg–1, 0.9 ± 0.0 g kg–1, 3.0 ± 0.5 g kg–1, and 1.6 ± 0.5 g kg–1, respectively), than those near the riverbank, which were 1.7 ± 0.7 g kg–1, 0.5 ± 0.2 g kg–1, 1.4 ± 0.3 g kg–1, and 0.6 ± 0.3 g kg–1, respectively. Based on the distribution of ash, exchangeable Ca2+ and Mg2+, and total Ca, Mg, Al, and Fe content, the present study suggests that the presence of the mineral upland nutritionally enriches the peat with Ca, Mg, and Fe. The influence of landform should be considered for a comprehensive understanding of nutrients sources in peatlands.

中文翻译：

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地形影响热带泥炭中矿质养分的分布：以印度尼西亚 Siak 泥炭地为例

摘要 印度尼西亚的大多数泥炭地都与矿质高地接壤，但关于矿质高地的存在对矿质养分分布的影响的研究是有限的。我们从位于印度尼西亚廖内省 Siak 河和矿物高地之间的泥炭地收集了多个表层样品，并测量了电导率、pH 值以及可交换的 Ca2+、Mg2+、K+ 和 Na+。研究横断面的灰分含量和其剖面的化学成分。尽管表层的电导率 (183 ± 79 μS cm–1) 和 pH 值 (3.7 ± 0.3) 相似，但可交换 Ca2+（尤其是靠近矿物高地）和 Mg2+ 在 0–15 cm 深 (8.3 ± 5.1 cmolc) 处较高kg–1 和 2.7 ± 1.1 cmolc kg–1），并在较低层趋于下降。可交换的 K+ 和 Na+ 没有表现出明显的趋势，可能是因为与泥炭材料的结合较弱。高灰分含量 (>10%) 在矿物高地附近比在河岸更频繁地被发现。在靠近矿物高地的剖面中，表层中的总 Ca、Mg、Al 和 Fe 含量较高（4.5 ± 0.3 g kg–1、0.9 ± 0.0 g kg–1、3.0 ± 0.5 g kg–1 和1.6 ± 0.5 g kg–1)，比靠近河岸的河床分别为 1.7 ± 0.7 g kg–1、0.5 ± 0.2 g kg–1、1.4 ± 0.3 g kg–1 和 0.6 ± 0.3 g kg– 1、分别。根据灰分、可交换 Ca2+ 和 Mg2+ 的分布以及总 Ca、Mg、Al 和 Fe 含量，本研究表明，矿物高地的存在使泥炭富含 Ca、Mg 和 Fe 的营养。全面了解泥炭地养分来源应考虑地形的影响。