STREAM WATER AND SOIL SOLUTION RESPONSES TO 5 YEARS OF NITROGEN AND SULFUR ADDITIONS AT THE FRENOW EXPERIMENTAL FOREST, WEST-VIRGINIA

To examine the effects of elevated N and S inputs on a central hardwoo d forest, a whole-watershed acidification experiment was initiated in 1989 on the Fernow Experimental Forest, West Virginia. Annual experime ntal additions of 40 kg S ha(-1) year(-1) and 35 kg N ha(-1) year(-1) as ammonium sulfate fertilizer were applied to a 34 ha watershed with a 25-year-old stand of central Appalachian hardwoods. An adjacent wate rshed served as the control. After 5 years of treatment (total additio ns of 275 kg S ha(-1) and 220 kg N ha(-1)), stream water NO3-, Ca2+, M g2+ concentrations and export increased. Soil solution concentrations provide evidence that the treatment watershed is nitro en saturated, w hich was unexpected for such a young stand. No statistically significa nt changes in annual SO42- export were observed, but peak stream water concentrations of SO42- did increase during the treatment period. Cha nges in soil solution chemistry suggest that the treated watershed als o may be approaching SO42- saturation. (C) 1997 Published by Elsevier Science B.V.