Growth dynamics and biomass accumulation of 8-year-old hybrid poplar clones in a short-rotation plantation on a clayey-sandy mining substrate with respect to plant nutrition and water budget

In 1995 a short-rotation plantation (2.5 ha) was established in the mining region Welzow-Sud in Brandenburg, Germany, on a clayey-sandy, lignite- and pyrite-free substrate in order to study the biomass potentials of fast-growing tree species (hybrid poplar clones). In this study, special emphasis was placed on yield aspects as well as on the interaction between soil and plants, especially with regard to the plant nutrition and soil-water relationships. So far, the results indicate that the cultivation of hybrid poplar clones in a short-rotation plantation is an adequate tool for establishing alternative land-use systems in the post-mining landscape as a potential source of biomass energy. Aboveground biomass production ranged from 24-49 t dry matter (DM) per hectare at age 8. In particular during this period of investigation, nitrogen nutrition of the clones decreased to below a threshold of 20 mg g(-1) supercript stop DM in the year 2002. Investigations of the water budget of low- and high-yielding clones indicated that differences in the biomass accumulation seemed to be accompanied by different water-use efficiencies.