Cation Cycling in a Base-poor and Base-rich Northern Hardwood Forest Ecosystem
- J. F. Thorne *,
- J. E. Anderson and
- K. M. Horiuchi
Biogeochemical cycles of Ca, Mg, K, and Na were studied in a small forested watershed on relatively base-rich terrain at the Sleepers River Research Watersheds (SRRW) in northeastern Vermont and on base-poor terrain at the Hubbard Brook Experimental Forest (HBEF) in central New Hampshire. The two watersheds are comparable except that shallower soils at the SRRW are weathered from calcareous and quartz mica schist till, whereas the deeper soils at the HBEF are weathered from schist, gneiss, and quartz monzonite till. Inputs of the four cations in precipitation were similar except for Ca; Ca inputs were an order of magnitude greater at the SRRW. Total annual cation outputs were more strongly related to total stream flow and parent material geochemistry than to cation inputs in precipitation. Analysis of the variation in cation output in stream water with respect to flow suggests strong geochemical control of cation output at the SRRW. Similar analysis of data from the HBEF suggests a more complex pattern of cation output related to biological cycling of cations. Inputs of acidity may serve to flush the soil at the HBEF of cations.
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