Growing of energy woods on water treatment sludge

The aim of the experiment was establishe growing ability of used woods on soil with applied water treatment sludge, accumulation of some elements and compare suitability of growing these woods for energy purposes. In year 2001 (March), the field trials were established in area of sewerage plant in Jindrichuv Hradec (478 m above sea level, average annual temperature 6.5 deg C , annual sum precipitation 620 mm) with energy woods grey poplar \{Populus canadiensis), balsam poplar (Populus balzamea), grey alder (Alnus incane), common alder (Alnus glutinosa) and European black pine (Pinus nigra) on four variants of substratum: a - only soil (kambisol) b - soil and raw water treatment sludge pro rata 1:1 c - one year old (mature) treatment sludge d - raw water treatment sludge. European black pine was intended for Christmas-trees production. Forty individuals were set out in spacing 0.3 x 0.5 m (in case of poplar cutting, the other woods seedlings) on 20 m/2 plot. No inter-row tillage was done during vegetation period. The height of plant and increase of dry matter were masured at the end of the vegetation. The experiments were harvested in November 2001. Height of plants and increase of shoot biomass were determined at the end of vegetation (November). Contents of Al, Cd, Co, Cr, Ni, Pb, Zn, Cu, Fe, Mn, Ca, K and Mg were analysed in samples of soil, sludge and plants by atomic absorption spectrometry - flame technique (Spektra A640) for determination their accumulation in woods. To compare easily the transfer of the selekted elemets from soil to plant, transfer-coefficients (TC -proportion of the content in plant or plant part to the content in soil) are calculated for every element, crop and experimental variant. Transfer coefficients describe the element uptake independently of the concentration and thus allow a comparison among various elements. Balsam poplar (Populus balzamea) can be recommended for next experimental growing, this species was the most suitable woods for decontamination of contaminated soil. For growing energy woods using water treatment sludge mixture soil and raw water treatment sludge pro rata 1:1 can be recommended.