Chemical and morphological distinctions between vertical and lateral podzolization at Hubbard Brook
Chemical and morphological distinctions between vertical and lateral podzolization at Hubbard Brook
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哈伯德布鲁克垂直和横向灰化作用之间的化学和形态差异
DOI：
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
S. Bailey
中科院分区：
文献类型：
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作者：
Rebecca R. Bourgault;D. Ross;S. Bailey
经典的灰化研究假设垂直渗流和土壤尺度的水平发展。然而，山坡规模的横向灰化也发生在横向地下水通量占主导地位。在这项水文土壤学研究中，观察了新罕布什尔州哈伯德布鲁克实验森林3号流域的99个灰壤。用柠檬酸盐-连二亚硫酸盐（d）和酸性草酸铵（o）提取土壤层样品，以定量测定Fed、Mnd、Alo和FeO。通过测定草酸盐抽提物的光密度（ODOE）来评价土壤中的黑腐质C.在薄切片中观察到无定形有机金属络合物（AOC），其中Al，Fe，Mn和C使用扫描电子显微镜-能量色散X射线光谱进行定量。使用ImageJ计算薄切片图像的孔隙率和AOC/矿物比。侧向发育的灰化层厚度是垂直发育灰化层厚度的2倍，灰化层中Al和Mn含量较高，Fe和C含量较低。垂直发育的灰化层孔隙度较高，呈碎屑状，侧向发育的灰化层孔隙度较低。铝+ 0.5Fe和ODOE在横向发展的灰壤表面高，缺乏对比度的灰化层，灰化土分类的问题。垂直发育的灰化层是在非饱和条件下AOC的溶解迁移和沉淀作用形成的。然而，横向发展的灰化层可以通过溶质的横向迁移或胶体AOC在非饱和或饱和水流中的物理迁移和沉积而形成。这项研究表明，侧向灰化在生产具有独特的形态，成分和分类的土壤的重要性。未来的研究或在灰化集水区绘图的努力，应包括这些不同的成壤过程。
Classical podzolization studies assumed vertical percolation and pedon-scale horizon development. However, hillslope-scale lateral podzolization also occurs where lateral subsurface water flux predominates. In this hydropedologic study, 99 podzols were observed in Watershed 3, Hubbard Brook Experimental Forest, New Hampshire. Soil horizon samples were extracted with citrate-dithionite (d) and acid ammonium oxalate (o) to quantify Fed, Mnd, Alo, and Feo. Optical density of oxalate extract (ODOE) was measured to assess spodic C. Amorphous organometallic complexes (AOC) were observed in thin section, for which Al, Fe, Mn, and C were quantified using scanning electron microscopy-energy dispersive X-ray spectroscopy. Porosity and AOC/mineral ratio were calculated for thin section images using ImageJ. Laterally developed spodic horizons were twice as thick as vertically developed spodic horizons and contained higher concentrations of Al and Mn but lower Fe and C. Vertically developed spodic horizons had crumb microstructure with higher porosity, while laterally developed spodic horizons were more infilled. Aluminum + 0.5Fe and ODOE in the surface of laterally developed podzols were high and lacked contrast with the spodic horizon, making Spodosol classification problematic. Vertically developed spodic horizons form by solutional translocation and precipitation of AOC under unsaturated conditions. However, laterally developed spodic horizons could form via lateral translocation of solutes or physical transport and deposition of colloidal AOC with unsaturated or saturated flow. This study demonstrates the importance of lateral podzolization in producing soils with distinctive morphology, composition, and classification. Future studies or mapping efforts in podzolized catchments should incorporate these different pedogenic processes.