Competition for nitrogen by three sympatric species of Eucalyptus

Abstract

Nitrogen (N) exists in the soil in a variety of different forms and thus plants may avoid competition by taking up N as different chemical forms. This study examined the uptake of nitrate, ammonium and glycine by three co-occurring species of Eucalyptus (E. obliqua, E. radiata and E. rubida) from dry sclerophyll forest in south-eastern Australia. Species preference for N forms was determined by measuring uptake of glycine, nitrate and ammonium from N-labelled solutions containing equimolar 100 μmol L concentrations of all three N forms. KCl extracts were used to assess the relative abundance of the different forms of N in the soil's exchangeable pool. KCl extracts of soil indicated that a..