Ratarstvo 45. hrvatski i 5. međunarodni simpozij agronoma 841 ORIGINAL SCIENTIFIC PAPER The role of wood ash in the forest nutrition Marianna Marozsán 1 , Éva Gajdos 2 , Nñra Bákonyi 2 , Brigitta Tñth 2 , Szilvia Veres 2 , Lászlñ Lévai 2 1 Nyírerdő Nyírségi Forestry Corporation, Kótaji út 29, Nyíregyháza, Hungary (marozsanm@nyirerdo.hu), 2 University of Debrecen, Institute of Plant Science, Division of Agricultural Botany and Crop Physiology, Böszörményi út 138, Debrecen, Hungary Abstract The effects of wood ash were investigation on the radial and height growth of tree. The relative chlorophyll contents, the concentration of some elements in the wood ash also were measured. The effects of wood ash are primarily governed by application rate and soil type. The benefits are maximized at higher low dose rates. For most forest sites, a single wood ash application per rotation could replace all the nutrients lost after whole-tree harvesting (excepting N). The greatest reported adverse ecological effects are to acidophilic ecosystems, particularly the constituent bryophyte, soil bacteria and ectomycorhizal communities. Key words: wood ash, height growth, chlorophyll contents Introduction It is claimed that the damage to European forests is caused by the acidification of soils. The acidic rain can be one of the reasons, but the decrease of cations in forest soils can also play a significant role in this process. The trees accumulate the minerals from the soils in several decades, and by the lumber of forest, as a consequence, large amounts of cations are also transferred from the field. These cations play a role in the maintenance of the buffer capacity of soils, removing the cations the buffer capacity decreases, the soils become more acidic, the uptake of heavy metals increases, which may cause toxicity and eventually the destruction of forests. The use of wood is expanding in power stations. The energy-forests and energy grasses will play an important role, as renewing energy resources, since the planting of these cultures are governmentally supported. Large amounts of minerals, in the form of wood ash, will be accumulated near the power stations, as a by-product, which may cause environmental damage if in high concentrations. To provide the sustainable soil quality, the buffer capacity of soils, it is necessary to complete the soils with minerals. It seems to be obvious, that the most economic solution can be to feed back the wood ash in order to maintain the sustainability of soils of forest, and energy grasses. The effect of wood ash was longer lasting in liming experiments and the production of crops was higher. The sustainability in agriculture means the maintenance of available nutrients (Husti, 2006). Increase of yields was observed in long term experiments, when the micronutrients were applied in an optimum level (Singh, et al. 2005). The potassium supply increases the yield (Kovaţeviš, et al., 2006), and the stress tolerance of crop plants. The main problem to use the wood ash in agriculture is its cadmium contents; although the cadmium is a natural component of our soils. The aim of this work was to investigate the effects of wood-ash for the development of some crop plants. Matherials and methods The experiments have been conducted at the 2 forest blocks of Nyìrerdő Forestry Corporation. The first block is Debrecen 294 H (Jñzsa) with chernozem brown forest soil.