Shepard, J.P., M.J. Mitchell, T.J. Scott and C.T.
Driscoll. 1990. Soil solution chemistry of an Adirondack
spodosol: Lysimetry and N dynamics. Canadian Journal of Forest
Abstract: Solutes were monitored from the soil of a beech-maple forest and an adjacent lake at the Huntington Forest in the Adirondack Mountains of New York. the predominant ions were Ca2+ and SO42-. For soil solutions collected by lysimeters, the highest concentrations of most ions (H+, K+, NH4+, Ca2+ , Mg2+, and NO3-) occurred in O horizon leachates, and the lowest concentrations beneath the spodic B horizon. However, A1 and SO42- concentrations were highest beneath the B horizon. concentrations of NO3- showed distinct seasonal variation. Values reach 60 equiv. L-1 in the spring and decreased to near zero late in the growing season. Coefficients of variation (CV) differed among horizons. The E horizon was generally mort variable (CV, 17 to 199%) and the B horizon the least (CV 19 to 166%). Variation was especially high for NO3- and NH4+, which had minimum Cvs of 124% and 122%, respectively. Variation in these ions was likely due to the dominant role of biological processes in affecting nitrogen dynamics. Differences in soil solution concentrations among six soil pits were mainly due to spatial variation in soil properties rather than differences among the four types of lysimeters (tension, zero tension, fritted glass, and ceramic plate). Nitrogen species showed the greatest response to the installation of lysimeters, with elevated concentrations of NO3- (120 to 160 equiv. L-1) observed during the first 2 years after installation. The high temporal and spatial variation of NO3- as well as its generation following lysimeter installation has important implications in assessing nitrogen dynamics of forest ecosystems.