Changes in soil, seepage water and needle chemistry between 1984 and 2004 after liming an N-saturated Norway spruce stand at the Höglwald, Germany

In 1984, a liming experiment with a surface application of 4 t ha−1 of dolomitic limestone was started at the acidic N-saturated Norway spruce forest “Höglwald” in southern Germany and monitored until 2004. The decay of surface humus due to the accelerated mineralisation accounted for 18.5 ± 2.7 t ha−1 C or 50% of the initial pool and 721.6 ± 115.0 kg ha−1 N or 46% for N. Due to some translocation of organic material to the mineral soil the values to 40 cm depth are slightly lower (13.5 ± 4.4 t ha−1 C or 15% of the initial pool and 631.6 ± 192.8 kg ha−1 N or 13% for N). In the control plot NO3− concentrations at 40 cm depth were above the European level of drinking water (0.8 mmolc l−1 or 50 mg NO3− l−1) for nearly the whole investigation period. Liming increased NO3− concentrations in seepage water for approximately 15 years, and accelerated leaching losses by 396.2 NO3−–N kg ha−1 from 1984 to 2003. The increase in pH of the soil matrix was more or less restricted to the humus layer and the upper 5 cm of the mineral soil during the whole time span, while the base cations Ca and Mg reached deeper horizons with seepage water. From 1984 to 2003, an amount that nearly equalled the applied Mg, was leached out of the main rooting zone, while most of the applied Ca was retained. The time series of the elemental concentrations in needles showed minor changes. Ca concentrations in needles increased with liming, while Mg remained nearly unchanged, and P decreased in older needles.