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Factors that Control the Range and Variability of Amorphous Silica in Soils in the Hubbard Brook Experimental Forest
Author(s) -
Saccone Loredana,
Conley Daniel J.,
Likens Gene E.,
Bailey Scott W.,
Buso Donald C.,
Johnson Chris E.
Publication year - 2008
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2007.0117
Subject(s) - soil water , biogeochemical cycle , environmental science , ecosystem , experimental forest , temperate forest , silt , soil horizon , deforestation (computer science) , biogeochemistry , hydrology (agriculture) , temperate climate , soil science , geology , ecology , environmental chemistry , chemistry , oceanography , geomorphology , geotechnical engineering , computer science , biology , programming language
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 (∼17,400 kg SiO 2 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.