Johnson, D.W., R.B. Susfalk, and W.T. Swank. 1998. Simulated effects of
atmospheric deposition and species change on nutrient cycling in
loblolly pine and mixed deciduous forests. Chpt. 27, pp.503-524
In: R. A. Mickler and S. Fox (eds.). The Productivity and
Sustainability of Southern Forest Ecosystems in a Changing Environment. Springer, New York.
892p.
Forest soils of the South, like those in several other parts of the
world, are undergoing changes which may have bearing upon the future
health and productivity of southern forest ecosystems. In this paper, we
explored the interacting effects of atmospheric deposition and species
change on soil changes through simulations with the Nutrient Cycling
Model (NuCM). Simulation results suggest that
changes in atmospheric deposition
can have major effects upon soil solution concentrations and the
distribution of soil nutrients within the profile, but little effect
upon overall soil capital or growth. Over the long-term, the
simulations suggest that, aside from N, P is the nutrient most likely
to become limiting with time in these forest ecosystems, and point to
a need for better information on atmospheric P deposition rates.
Finally, the simulations suggest that replacement of pines by
hardwoods or vice-versa causes large differences in Ca uptake and
accumulation by vegetation. This in turn causes a chain of events
(increased Mg leaching, reduced base saturation, reduced soil solution pH,
bicarbonate, and sulfate leaching) which significantly alters the fluxes
and accumulation of most other nutrients in the system. Many of these
changes have been corroborated in field studies of loblolly pine and
mixed deciduous forests near Oak Ridge, Tennessee.