Average plant dry weight at the start of the experiment was
calculated based on the 12 randomly selected plants of Iris and
Typha. Total removal capacity was calculated by determining the
total amount of nutrients added to each tank minus the amount of
TN and TP present in the tank at the end of the experiment (TN and
TP concentrations multiplied by the water volume). To determine
plant uptake of nitrogen and phosphorous during the experiment,
(estimated) dry weight at the start and end of the experiment was
multiplied by TN and TP tissue concentrations at both time points.
We did not correct for the addition of nutrients attributable to the
addition of groundwater after evapotranspiration because this
amount was negligible in comparison to the nutrient additions
attributable to Pokon and KNO3