Prairie cordgrass is a perennial C4 grass characterized by high adaptability to different habitats. The highest yields are obtained on sites with sufficient water supply, on soils of coarse or medium texture and with a wide range of the C:N ratio. Sewage sludge may be the source of nutrients for the crops grown for renewable energy purposes. The objective of the research was to evaluate the effect of sewage sludge fertilization on the growth and yield of prairie cordgrass and the content of crude ash, macronutrients and heavy metals in the plant biomass in the first three years of cultivation. The experiments were conducted at the Pawłowice Agricultural Experimental Station near Wroclaw, in 2008-2010. Their aim was to investigate the impact of differentiated sewage sludge applications and harvest periods on the growth, yield formation and chemical composition of prairie cordgrass. Two-factor experiments in a split-plot design were conducted. The first factor was a dose of sewage sludge: 0, 1.4, 2.8 and 4.2 t ha-1 DM, corresponding to the nitrogen fertilization of 0, 50, 100, 150 kg ha-1, and the second factor was the harvest time: autumn and winter. The sewage sludge dose of 2.8 t ha-1 DM, compared to the control, significantly increased the plant height by 4%, one shoot mass by 11%, the number of shoots per 1 m2 by 14% and the dry mass yield by 22%, but it showed no influence on the yield structure formation and the content of macronutrients and heavy metals. The postponement of the harvesting time from autumn to winter resulted in drier plants, lower dry mass yield and less crude ash, K, Mg and S.

19.4.2014