Acidification and pH Buffering of Forest Soils1
- F. R. Magdoff,
- R. J. Bartlett and
- D. S. Ross2
Horizons (O, A, E, B, and C) of forest soils from Vermont, New York, New Hampshire, and Virginia were equilibrated with various rates of either acid (H2SO4) or base (CaCO3). Most titration curves had a logistic shape with a lower asymptote (between pH 0.3 and 3.1) and an upper asymptote (around pH 7). The lower pH asymptote was highly correlated with equilibration solution Al and with soil pH measured in 1 M NaF. The specific buffer capacity (SBC) of the 26 horizons was related to organic matter (OM). Higher OM levels caused greater SBC. The buffer capacity of the OM was 0.4 mol kg−1 OM−1 pH−1. Using pH, pHNuF, OM, and horizon depth, it is possible to estimate the amount of acid currently in the soil (compared to a reference pH), the quantity of acid needed to lower the pH by a given amount, the amount of pH decrease associated with a given amount of acid input, the lower pH asymptote, and the pH at which solution Al is above a given concentration.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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