Allelopathic properties of selected lawn cultivars of Poa pratensis and their utilization in garden compositions

The study objective was to assess the impact of the vegetative shoots of the lawn cultivars of Poa pratensis (one of the most valuable lawn grasses), cut and left on the lawn surface, on the species composition and overwinter survival of a lawn. The investigation was conducted in a field experiment. Each cultivar was sown in monoculture, on microplots covering 1 m2 each. In the control objects, the cut biomass was removed immediately after the cutting. The investigation showed that ‘Bila’ had the strongest negative impact on the share of sown lawn grass cultivars (sensitivity to the biomass of the same cultivar remaining after cutting). The smallest share of other, unsown grass species in objects where the cut biomass remained was observed in lawns with ‘Nandu’ and, in the case of dicotyledons – with ‘Bila’. The biomass left on the lawn surface after cutting did not have a significant influence on the overwinter survival of the plants. The negative impact of P. pratensis biomass, both on the sown cultivars and other groups of plants, can indicate its allelopathic properties. Therefore, the grass of this species should not be left on the lawn after cutting. The aboveground biomass cut and left on the lawn surface was shown to have a clearly varied influence on the soil pH: in the case of the ‘Ani’ and ‘Bila’ cultivars, the influence was unequivocally negative. In addition, the biomass of these cultivars did not result in significantly increased levels of assimilable forms of phosphorus, potassium and magnesium in the soil.