Forest Soil Nutrient Status After 10 Years of Experimental Acidification and Base Cation Depletion: Results From Two Long-Term Soil Productivity Sites in the Central Appalachians.

Soil base cation depletion is hypothesized as an important effect of acidic deposition for forests, particularly in the central Appalachians.  In 1996 a study was begun to assess the effects of experimentally induced base cation depletion on long- term soil  productivity and evaluate the sustainability of forest stands.  To induce base cation depletion a combination of treatments were used: Whole-tree harvesting was used, along with removal of all down dead wood, to remove all aboveground nutrients.  Additions of ammonium sulfate fertilizer, at annual rates of 40.6  kg S/ha and 35.4 kg N /ha, have been applied since study initiation to increase the leaching of Ca and Mg from the soil, based on results from the Fernow Watershed Acidification Study.   The study was designed as a randomized complete block design, with 4 replication of  4 (or 5) treatments in each of two forests: a mixed hardwood forest on the Fernow Experimental Forest, WV, and a cherry-maple forest located on the Monongahela National Forest, WV.   Soils have been sampled repeatedly over the 10 years since the study began, and changes over time are evaluated.  There have been significant changes in soil Ca, N and some other nutrients over time, however the differences among the treatments have been less than we had hypothesized.  The differences due to forest characteristics are discussed, and preliminary data on diversity of herb layer species is also discussed.