Soil S constituents were evaluated before and after the whole-tree harvesting of Watershed 5 (W5) at the Hubbard Brook Experimental Forest, New Hampshire. Soil solution and stream water concentrations of SO4/2-, NO3/-, and H+ were compared between W5 and W6 (reference watershed). Whole-tree harvesting increased phosphate-extractable SO4/2- (PSO4) in the E horizon, from 2 mg S · kg-1 soil in pre-harvest to 9 and 10 mg S · kg-1 soil 3 and 8 years post-harvest, respectively. Harvesting increased PSO4 in the Bh horizon from 11 mg S · kg-1 soil prior to harvesting to 20 and 25 mg S · kg-1 soil 3 and 8 years after harvesting, respectively. Temporal patterns in soil chemistry were also reflected in stream SO4/2-, NO3/-, and H+ concentrations. Eight years after harvesting, PSO4 concentrations in the mineral soil increased with elevation. This elevational pattern was likely due to the higher concentrations of SO4/2- and H+ in soil solutions that enhanced SO4/2- adsorption at the higher elevations. The high H+ concentrations were attributed to enhanced nitrification and differences in vegetation at upper elevations. The importance of these factors were discussed with respect to the effects of forest harvesting and changes in atmospheric S deposition.
ASJC Scopus subject areas
- Global and Planetary Change