Fig. 4. Soil pH in water (pH H₂O); exchangeable Ca (Ca_ex), Mg (Mg_ex), Mn (Mn_ex) and Al (Al_ex); and H₂O-soluble SO₄ (SO₄–H₂O) in the B horizons of the Hermine watershed for the period 1993 to 2002, inclusively. The lines represent the simple linear regression for the data of each of the three zones (Zone A: dashed line; Zone B: dotted line; and Zone C: full line).