Effects of competition and N and P supply on carbon isotope discrimination and 15N-natural abundance in four grassland species

Abstract

The effect of interspecific competition and element additions (N and P) on four grassland species (Poa pratensis, Lolium perenne, Festuca valida, Taraxacum officinale) grown under field conditions was studied. Two grasses (L. perenne, F. valida) grown in monoculture (absence of competition) showed lower carbon isotope discrimination (Δ13C) and enriched δ 15N values. Nitrogen addition (as urea) had inconsistent effects on species Δ13C while caused enrichment of δ15N of P. pratensis and F. valida but strong depletion of δ15N of T. officinale. Phosphorous had no significant effect on Δ13C but depleted δ 15N of all species.