EFFECT OF NITROGEN ON THE DISTRIBUTION OF BIOMASS AND ELEMENT COMPOSITION OF THE ROOT SYSTEM OF MISCANTHUS x GIGANTEUS

Perennial bioenergy grass crops, despite a relatively similar production of aboveground biomass, show significant differences in the overall root biomass. Rhizomes play a key role in economizing nutrients in miscanthus. The aim of this research was to establish the effect of N (nitrogen) on the distribution of biomass and concentration of major macro- and micronutrients in the miscanthus root system, using simple experiment in pots. After two years of growth, the rhizomes and roots were taken out of the pots, cleaned of earth and analyzed. About 2/3 of the mass of the miscanthus root system consist of rhizome mass. The overall dry biomass of newly formed rhizomes and roots is decreased with the increase in the amount of applied N fertilization. Thereby, the N concentration in the entire root system, as well as in some of its parts, increased with the rise in applied amount of N. Our results show that increasing amounts of applied N consistently negatively correlate with P concentrations in the miscanthus root system, in contrast to Mn concentrations, with which they correlate positively.