Fig. 2. Effect size of the ratio between potential root-associated denitrification and plant N-uptake rates of plant species growing in situ for the vegetation period (ln mean ± SE, n ¼ 5). Values above and below zero indicate denitrification and plant N- uptake, respectively, as the main N-removal pathway. Different letters above the bars indicate significant differences among plant species (p < 0.05). Asterisks denote a significant difference between plant uptake and denitrification within each species (p < 0.05).