Ij. Fernandez et al., SOIL-SOLUTION CHEMISTRY IN A LOW-ELEVATION SPRUCE-FIR ECOSYSTEM, HOWLAND, MAINE, Water, air and soil pollution, 84(1-2), 1995, pp. 129-145
Soil solutions were collected monthly by tension and zero-tension lysi
meters in a low-elevation red spruce stand in east-central Maine from
May 1987 through December 1992. Soil solutions collected by Oa tension
lysimeters had higher concentrations of most constituents than the Oa
zero-tension lysimeters. In Oa horizon soil solutions growing season
concentrations for SO4, Ca, and Mg averaged 57, 43, and 30 mu mol L(-1
) in tension lysimeters, and 43, 28, and 19 mu mol L(-1) in zero-tensi
on lysimeters, respectively. Because tension lysimeters remove water h
eld by the soil at tensions up to 10 kPa, solutions are assumed to hav
e more time to react with the soil compared to freely draining solutio
ns collected by zero-tension lysimeters. Solutions collected in the Bs
horizon by both types of collectors were similar which was attributed
to the frequency of time periods when the water table was above the B
s lysimeters. Concentrations of SO4 and NO3 at this site were lower th
an concentrations reported for most other eastern U.S. spruce-fir site
s, but base cation concentrations fell in the same range. Aluminum con
centrations in this study were also lower than reported for other site
s in the eastern U.S. and Ca/Al ratios did not suggest inhibition of C
a uptake by roots. Concentrations of SO4, Ca, K, and Cl decreased sign
ificantly in both the Oa and Bs horizons over the 56-month sampling pe
riod, which could reflect decreasing deposition rates for sulfur and b
ase cations, climatic influences, or natural variation. A longer recor
d of measured fluxes will be needed to adequately define temporal tren
ds in solution chemistry and their causes.