摘要：The paper herein identifies biological factors affecting the growth and biomass production of fast-growing energy woody crops of Salix genus. Experimental data on the growth rate, leaf area index (LAI), biomass production and dynamics of the assimilation pigments is in leaves were obtained in 2009 and 2010 in the stand of five fast-growing willow varieties of Swedish origin. The three-year old willow stands (first rotation cycle) were established on agricultural land belonging to SUA in Nitra in the cadastre of Kolíňany village. Other studied biological factors included the health of the willows and identification of impacts of diseases and pests on the observed willow varieties. The paper also discusses the impact of the weed competition. The fact that growth and biomass production are genotype-conditioned was confirmed. The determining factors are the leaf area index, the length of its functional activity and the content of assimilation pigments, which is in linear correlation with the size of LAI. The size of LAI and its dry weight decreased due to leaf area losses caused by pests and diseases as well as the premature defoliation. The European Union established a common framework for the promotion of renewable energy. The EU member states, among them also Slovakia, prepared their long term strategies concerning agricultural and non-agricultural use of crops for industrial purposes.
