Institute of Geophysics of the Czech Academy of Sciences, Boční II/1401, 141 31 Prague 4, Czech Republic.
Faculty of Forestry and Wood Sciences, Czech University of Life Sciences, Kamýcká 129, 165 00 Prague 6, Czech Republic.
Sci Total Environ. 2018 Jun 1;626:228-234. doi: 10.1016/j.scitotenv.2018.01.095. Epub 2018 Feb 19.
The effect of wood-ash fertilization on forest soils has been assessed mainly through geochemical methods (e.g., content of soil organic matter or nutrients). However, a simple and fast method of determining the distribution of the ash and the extent of affected soil is missing. In this study we present the use of magnetic susceptibility, which is controlled by Fe-oxides, in comparing the fertilized soil in the forest plantation of pine and oak with intact forest soil. Spatial and vertical distribution of magnetic susceptibility was measured in an oak and pine plantation next to stems of young plants, where wood ash was applied as fertilizer. Pattern of the susceptibility distribution was compared with that in non-fertilized part of the plantation as well as with a spot of intact natural forest soil nearby. Our results show that the wood-ash samples contain significant amount of ferrimagnetic magnetite with susceptibility higher than that of typical forest soil. Clear differences were observed between magnetic susceptibility of furrows and ridges. Moreover, the dispersed ash remains practically on the surface, does not penetrate to deeper layers. Finally, our data suggest significant differences in surface values between the pine and oak plants. Based on this study we may conclude that magnetic susceptibility may represent a simple and approximate method of assessing the extent of soil affected by wood-ash.
草木灰施肥对森林土壤的影响主要通过地球化学方法（如土壤有机质或养分含量）进行评估。然而，目前还缺乏一种简单快速的方法来确定灰分的分布和受影响土壤的范围。在本研究中，我们提出了利用磁化率（受铁氧化物控制）来比较松林和橡树林种植园中施肥土壤与未受干扰森林土壤之间的差异。在靠近幼树树干的地方，我们测量了橡树和松林种植园中磁化率的空间和垂直分布，那里曾施用草木灰作为肥料。我们将磁化率的分布模式与种植园中未施肥部分以及附近未受干扰的天然森林土壤的分布模式进行了比较。结果表明，草木灰样本中含有大量的亚铁磁性磁铁矿，磁化率高于典型森林土壤。沟壑和山脊之间的磁化率存在明显差异。此外，分散的灰分实际上仍停留在表面，不会渗透到更深的土层。最后，我们的数据表明，松树和橡树之间的地表值存在显著差异。基于这项研究，我们可以得出结论，磁化率可能是评估土壤受草木灰影响程度的一种简单近似方法。
