LAUSR

Nutrient uptake by plants in nutrient-rich water in competitive conditions was investigated with two mixed culture combinations of Limnocharis flava/Pistia stratiotes and Limnocharis flava/Ipomoea aquatica by using various initial planting densities. Further, the biomass production and other growth-related parameters were measured to understand the dominant competitive behavior. The effects of interspecific competition on influencing nutrient uptake were substantial. In both experiments, the superior competitor produced a higher biomass regardless of the initial density, which was the dominant factor in determining the total nutrient uptake from water. Both aboveground competition and belowground competition appeared to be important in influencing competitive outcomes. Optimal removal of nutrients was produced by a treatment ratio of 5.31: 5.31 Limnocharis flava/Ipomoea aquatica plants/m2, which gave the highest observed nutrient removal, of which approximately 52% of TN removal and 90% of TP removal were due to plant uptake.