Biomass production for the replacement of fossil fuels is one of the pillars of the EU strategy for use of renewable energy sources. In Europe, the most commonly used crop for biomass, especially for biogas production is maize which growing area expand the last few years very much. Maize growing in a sustainable way is difficult because of many factors limiting the cultivation of this crop. The cultivation of perennial plants and perennial grasses could be a good alternative for sustainable farming and for the replacement of annual plants in crop rotation.

The aim of the paper was to assess the effect of plantation establishing methods and various harvest dates on biomass production from perennial novel crops Sida hermaphrodita L. Rusby (Sida) and Silphium perfoliatum L. (Silphium) grown on marginal soil in north-western Poland.

The field experiment was conducted at the Agricultural Experimental Station of the West Pomeranian University of Technology in Szczecin in the years 2016-2020 on the light rust-brown sandy soil of a poor rye complex. The experiment was two-factorial: factor A — Virginia mallow (Sida hermaphrodita L. Rusby) and cup plant (Silphium perfoliatum L.) and factor B — a method of establishing a plantation using seeds (seed) and seedlings (planting). Moreover, the additional factor of the number of harvests in a season was introduced: one or two. The experiment was set-up at the turn of May 2016 in a split-plot design in four replications.