Forest restoration on degraded sites
In Central Europe many forest soils are highly acidified. In the future management of forests concepts have to be developed as to, how reclamation of these soils can be achieved. Liming and fertilizing is one option, which may be combined with the selecti
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Abstract In Central Europe many forest soils are highly acidified. In the future management of forests concepts have to be developed as to, how reclamation of these soils can be achieved. Liming and fertilizing is one option, which may be combined with the selection and planting of site-specific tree species and with the establishment of an appropriate soil vegetation and shrub layer. A field experiment in the SoIling region, Germany, is presented, where a highly acid soil (Oystric Cambisol) was limed and fertilized to study the effects on soil chemical changes. After a clear cut of the former spruce stand, lime was applied either on the soil surface at a dose of 4 t ha- I (LIM) or was mixed (22 t ha- ' ) with deeper soil by ploughing to ameliorate both the surface and the deeper soil acidity (LPF). In addition on LPF plot 50 kg K ha- I and 105 kg P ha- I were applied. European beech, Norway spruce and black alder were planted in mixed stands. Five years later soil solution concentration and soil solid phase were studied. In LIM pH, effective CEC, and exchangeable Ca and Mg increased in the litter layer. In the surface mineral soil (0-5 cm) of LIM only exchangeable Mg was higher. In LPF a base saturation of 40·50% was achived up to 70 cm depth. In the soil solutions from 20-30 cm depth alkalinity, Ca and Mg concentrations increased but Al concentration decreased in LPF, whereas in LIM Ca and Mg increase was the only change. At I m depth Ca in soil solution increased in LPF and Mg in LIM and LPF. Initially, mean N03 concentrations in the soil solutions of all treatments were 100-700 flmol L- 1. Afterwards, when dense vegetation cover had developed, N03concentrations decreased to 10-100 flmol L- 1• It is concluded, that mixing sufficient quantitiy of lime with the soil by ploughing or other means can ameliorate acidity of the whole soil solum within a few years, whereas lime applied on the soil surface may need more time to become effective. Nitrate losses with seepage water may be minimized by establishing a dense vegetation cover. Key words: cation exchange, base saturation, soil solution, calcium, magnesium, nitrate A. Dohrenbusch et al. (eds.), Forest Development © Springer-Verlag Berlin Heidelberg 2002
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K. J. Meiwes
4.1.1 Introduction
Forest soils of central Europe are highly degraded chemically, and as estimated by Vanmechelen et a!. (1997), 25% of the forest soils can be regarded as highly acid. The high level of soil acidity is partly due to the history of the land use, associated with excessive exploitation for a long time in the past, and partly due to the accentuated acidification process that has occurred due to high atmospheric acid inputs during the last few decades. Acidification is associated with the loss of base cations from the soil that can lead to high growth risk by lowering the vitality of trees. In highly acid soils, the trees tend to produce flat root systems, with only restricted access to soil volume for the uptake of nutrients and water. The regeneration (amelioration) of such soil
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