Table 2 shows that
about 50% of the nitrogen were stored in the leaves of the
plants. This suggests routine aboveground biomass harvesting
may improve the overall nitrogen removal efficiency of
the wetland. In fact, based on the laboratory- and pilot-scale
experimental results, Koottatep and Polpresert reported that
the maximum total nitrogen removal of 84±86% and nitrogen
uptake rate of 7.1±7.5 kg/ha/day were achievable if the
plants were harvested once in 8 weeks.
to constitute 22 8% and 26 8% of the total nitrogen input.
Although these values are lower than the value of 55%
reported by Breen (1990) and 43% by Koottatep and
Polpresert (1997), they do indicate that plant uptake is one
of the major nitrogen removal pathways.