The Stratigraphy and Composition of a Lakeside Wetland1
- C. A. Johnston,
- G. B. Lee and
- F. W. Madison2
Soils were examined at 35 locations and described in detail at 22 locations to determine the stratigraphy and distribution of materials in a lakeside wetland in Wisconsin. Histic and mineral soil samples were analyzed for organic P, inorganic P, ammonium, nitrate, and organic N. Particle size distributions were determined for the mineral soils. It was found that soils formed in the wetland are young, not well developed, and derived from a variety of parent materials: glacial till, glacio-fluvial deposits, lacustrine deposits, histic materials, colluvium, and alluvium. Major soils in the wetland include Borosaprists, Haplaquents and Fluvaquents. Phosphorus concentrations are highest in silt loam alluvium and histic deposits, and lowest in glacio-fluvial deposits, marl, and sandy alluvium. Total P in the alluvium and glacio-fluvial deposits is very highly correlated (P <0.01) with percent silt plus clay. Nitrate concentrations were highest in silt loam alluvial levees and lowest in a saturated Histosol, indicating that the build-up of levees in the wetland has created aerobic soil conditions locally conducive to nitrification. The accumulation of histic materials and marl in the wetland has been an ongoing process since deglaciation, but deposition of alluvium appears to have occured primarily since logging and cultivation of the watershed began in the mid-1800's. The rate of Histosol accumulation in the wetland was estimated by 14C dating as 0.17 cm/year, no more than one third of the rate of alluvial deposition. Since P concentrations are slightly higher in the silt loam alluvium than in the histic materials, alluvial deposition is more effective than Histosol formation for retaining phosphorus in the White Clay Lake wetland.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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