Factors that Control the Range and Variability of Amorphous Silica in Soils in the Hubbard Brook Experimental Forest
Factors that Control the Range and Variability of Amorphous Silica in Soils in the Hubbard Brook Experimental Forest
复制标题
控制哈伯德溪实验林土壤中无定形二氧化硅范围和变化的因素
DOI：
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
C. Johnson
中科院分区：
文献类型：
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作者：
L. Saccone;D. Conley;G. Likens;S. Bailey;D. Buso;C. Johnson
在陆地生态系统中，土壤中储存着最大的无定形硅（ASi）库，是全球硅地球化学循环中生物活性硅的重要储存库。只有有限的数据可以量化这个水库的大小，这些估计往往是从淤泥大小的植硅体的物理分离，这可能会低估ASi池。从五个流域的温带大陆生态系统在哈伯德布鲁克实验森林，新罕布什尔州，土壤样品进行了分析，ASi使用碱消化。从两个流域的土壤进行了分析后，实验性的森林删除。在未受干扰的流域，ASi集中在土壤剖面的表面，类似于有机质，然后逐渐减少，随着深度。这项调查支持我们的假设，森林干扰导致土壤中的硅重新分配。事实上，尽管森林砍伐导致上层土壤中的ASi显著减少，但总剖面ASi（类似于17，400 kg SiO2 ha（-1））基本保持不变，这意味着向下转移。随着森林的砍伐，河流对溶解硅（DSi）的输送量显著增加，然而，土壤中的ASi库可能起着重要作用。更多的研究应针对ASi作为缓冲区的DSi损失从砍伐森林流域的潜在作用。（减）
In terrestrial ecosystems, the largest pool of amorphous silica (ASi) is stored in soils and is an important reservoir of biologically active Si for the global biogeochemical cycling of Si. Only limited data are available that quantify the size of this reservoir and often these estimates are made from the physical separation of silt-sized phytoliths, which can underestimate the ASi pool. Soil samples from five watersheds in a temperate-zone continental ecosystem at the Hubbard Brook Experimental Forest, New Hampshire, were analyzed for ASi using alkaline digestion. Soils from two of the watersheds were analyzed after experimental forest removal. In undisturbed watersheds, ASi was concentrated at the surface of the soil profile, similar to organic matter, and then progressively decreased with depth. This investigation supports our hypothesis that forest disturbance leads to redistribution of Si in the soil. In fact, although deforestation led to significant decreases in ASi in the upper soil horizons, total profile ASi (similar to 17,400 kg SiO2 ha(-1)) remained essentially unchanged, implying translocation downward. Significant increases in the transport of dissolved silica (DSi) by rivers have been observed With deforestation, however, in which the ASi pool in soils may play an important role. Additional studies should target the potential role of ASi as a buffer for DSi losses from deforested watersheds. (Less)