Abstract
Little fractionation of nitrogen isotopes was observed during the uptake of nitrate and ammonia by a hydroponic experiment with Artemisia princeps. δ15N of the plants indicated a value close to the fertilizer in inorganic fertilizer plots, but lower than the fertilizer in organic fertilizer plots.δ15N of wet irrigation plots in a potassium nitrate plot and an organic fertilizer plot was significantly lower than standard irrigation plots. This suggests that denitrification occurred in the wet plots.
δ15N of nitrated nitrogen in Kokaigaike pond water was 15.8‰.δ15N of the plants on the waterside was 10.7‰, and for plants that depended on the nitrogen supplied from rainfall was-3.6‰. Approximately three quarters of the nitrogen that was absorbed by the waterside plants appeared to be derived from the pond water.
