Nutrition and Early Growth of Pinus sylvestris L. on Extensively Meliorated Sandy Mine Spoil Soils

Based on common reclamation practice for lignite-rich and strongly acidic mine spoil soils today lignite-poor sandy mine spoils, which are more favorable for plant growth, are also reclaimed using the same intensive soil improvement measures to establish forest stands. The present study shows that intensive amelioration measures, e.g. loosening of the spoil, liming of the substratum and application of mineral fertilizers, are not a prerequisite for successful development of pine stands (Pinus sylvestris L.) on these substrata. The success of afforestation on these substrata depends more on the weather conditions after planting than on the soil conditions. In 1996 high temperatures and a long drought period after planting led to high mortality rates among the pine seedlings. Without any fertilization (K) and amelioration with silicate rock powder (W) the mortality rate amounted to 40% and 37%, respectively. Thus, amelioration with N-enriched silicate rock powder (RF) increased the mortality rate to 78% and re-planting was necessary. However, if planting takes place with sufficiently high soil water contents in the rooting zone (1997 and 1998) the mortality rate decreased to 11% on the control (K). Under these climatic conditions soil amelioration (W, RF) led to a mortality rate of up to 63%. Fertilization is not necessary at afforestation. Despite the nutrient poverty of the sandy substratum, nutrient storage in these raw soils is high enough to cover the nutrient demand of the pine seedlings during the first years after planting. Six years after application of silicate rock powder the effect of fertilization is seen in a larger growth as compared to the untreated control and to fertilization with N-enriched silicate rock powder (RFII and RFIII). Both, fertilization with silicate rock powder and N-enriched silicate rock powder led to improved N-, P-, K- and Mg-nutrition status of the pine needles compared to the untreated control. Three years after fertilization, N-, and K-concentrations in pine needles are higher compared to NPK-mineral fertilization. With regard to sustainability and from the ecological point of view silicate rock powder can be recommended as an alternative to the traditional reclamation practice of using mineral fertilizers.