Effect of vegetation on soil C, N, P and other minerals in Oxiso Is at the forest-savanna transition zone of central Africa
Effect of vegetation on soil C, N, P and other minerals in Oxiso Is at the forest-savanna transition zone of central Africa
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中非森林-稀树草原过渡带奥克索地区植被对土壤C、N、P及其他矿物质的影响
DOI：
10.1080/00380768.2013.866523
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发表时间：
2014
影响因子：
2
通讯作者：
Funakawa Shinya
中科院分区：
文献类型：
--
作者：
Sugihara Soh;Shibata Makoto;Mvondo Ze A.;Araki Shigeru;Funakawa Shinya
森林-稀树草原过渡带是过去气候变化的结果，广泛分布在非洲中部。由于养分贫乏的土壤（氧化土）在该地区广泛分布，因此有必要了解土壤养分与植被的关系。我们从该地区两种不同植被类型（森林和稀树草原）的5个坑中采集了52个土壤样品，并评估了植被类型对土壤理化性质[pH、土壤质地、阳离子交换量、容重、结晶和非结晶铝（Al）和铁（Fe）]和养分状况[碳（C）、氮（N）、磷（P）和其他土壤矿物质]的影响。我们还评估了分馏P.而大多数的物理化学性质是相似的两种植被类型之间的整个土壤剖面（0-80厘米深），粘土含量，容重和土壤pH值明显不同的植被在表层（0-10厘米）。在80 cm土壤深度，森林中土壤C、N和P分别为87.9、7.7和3.7 Mg ha−1，稀树草原中分别为98.6、7.1和3.1 Mg ha−1。虽然土壤C、N、P含量无明显差异，但森林土壤表层（0-40 cm）C：N比（11.0-12.0）明显低于草原（13.0-15.7），这是由于森林中主要植物能有效地固定N。我们还发现，氢氧化钠（NaOH）提取的无机磷在森林土壤全磷的比例较小，与稀树草原相比。由于森林土壤中结晶态和非结晶态Al、Fe含量与草原相近，不同的土壤C：N比会导致不同植被类型对P的有效性不同，但其机制尚不清楚。这些结果表明，稀树草原植被是N-有限的，森林植被是N-饱和（和可能的P-有限）在这个带。我们还发现，在20 cm土壤深度，森林中的土壤全钾（K）为1590 kg ha−1，比稀树草原（2520 kg ha−1;P< 0.05）少930 kg ha − 1，尽管Na、Ca和Mg没有测量到类似的差异。由于森林土壤pH值较低，不仅植物吸收钾，而且钾的淋溶损失将有助于降低森林土壤钾。
The forest-savanna transition zone, which evolves as a result of past climate change, is widely distributed in central Africa. Because nutrient-poor soils (Oxisols) are widely distributed in this area, it is necessary to understand the characteristics of soil nutrients in relation to the vegetation. We collected 52 soil samples from five pits each for two different vegetation types (forest and savanna) in this area and evaluated the effect of vegetation type on soil physicochemical properties [pH, soil texture, cation-exchange capacity, bulk density, crystalline and non-crystalline aluminum (Al) and iron (Fe)] and nutrient status [carbon (C), nitrogen (N), phosphorus (P) and other soil minerals]. We also evaluated the fractionated P. Whereas most physicochemical properties were similar between the two vegetation types throughout the soil profile (0–80 cm depth), clay content, bulk density and soil pH clearly differed between the vegetations at the surface layer (0–10 cm). At 80 cm soil depth, soil C, N and P were 87.9, 7.7 and 3.7 Mg ha−1, respectively, in forest, and 98.6, 7.1 and 3.1 Mg ha−1, respectively, in savanna. Although there was no clear difference between the amounts of soil C, N and P, the upper-soil (0–40 cm) C:N ratio was clearly lower in forest (11.0–12.0) compared with savanna (13.0–15.7), because the main plant species in the forest can fix N effectively. We also found a smaller ratio of sodium hydroxide (NaOH)-extractable inorganic P to total soil P in forest compared with savanna. Because the content of crystalline and non-crystalline Al and Fe in forest soil was similar to that of savanna, the different soil C:N ratio would cause different availability of P between the vegetation types, although the mechanism is unclear. These results indicate that savanna vegetation is N-limited and forest vegetation is N-saturated (and possibly P-limited) in this zone. We also found that, at 20 cm soil depth, total soil potassium (K) in forest was 1590 kg ha−1, which was 930 kg ha−1less than that in savanna (2520 kg ha−1;P< 0.05), although a similar difference was not measured for Na, Ca, and magnesium (Mg). Because we observed lower soil pH in forest, not only plant K uptake but also K leaching loss would contribute to lower soil K in forest.