Acid rain and soils of the Adirondacks. I. Changes in pH and available calcium, 1930-1984
1994
Johnson, A.H. | Anderson, S.B. | Siccama, T.G.
Interest in acid rain effects led us to resample 48 Adirondack soil profiles that had been sampled by Carl C. Heimburger in 1930-1932. Changes in pH and dilute-acid-extractable Ca were detected in 1984, which differed by horizon and were dependent on initial conditions. Moderately acidic organic horizons (pH 4.0) showed substantial decreases in pH and extractable Ca, while strongly acidic organic horizons (pH 4.0) showed a significant reduction in extractable Ca without a reduction in pH. The E horizons appeared to lose extractable Ca, while the B and C horizons showed no evidence of acidification. A partial Ca budget for the greater than or equal to 50-year interval for 16 sites in a mixed hardwood-softwood forest showed that Ca uptake was approximately equal to the loss of Ca from the soil, suggesting that this was a major cause of acidification. Acid-consuming processes apparently balanced acid additions in B and C horizons as no acidification was observed. While acid rain has increased hydrogen-ion loading and base-cation leaching, we did not find evidence of serious impacts on bulk soil chemistry in the Adirondacks through the mid-1980s
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