Influence of nitrogen supply rates on growth and nutrient storage by water hyacinth eichhornia crassipes plants
Reddy, K.R.; Agami, M.; Tucker, J.C.
Aquatic Botany 36(1): 33-44
The effect of nitrogen (N) levels of the culture medium (0.5-50.5 mg N l-1 or 38-3820 mg N m-2 day-1) on net productivity and nutrient (N, phosphorus (P) and potassium (NK)) storage by water hyacinth (Eichhornia crassipes (Mart.) Solms) plants was investigated using outdoor tanks. Net productivity increased with N supply rate of up to 5.5 mg N l-1 (or 416 mg N m-2 day-1); higher concentrations did not significantly increase the yield. The net productivity increased until plant tissue N content reached 16 mg N g-1 dry weight, but additional increase in tissue N content did not improve yield. However, N storage in the plant tissue increased in response to N supply rate with maximum N storage (80 g N m-2) measured in plants cultured at 50.5 mg N l-1. Plant density affected N storge in the tissue; when water hyacinths were cultured in N-limited water, plant tissue-N decreased by 75% within 4 weeks of growth. The storage of P and K in the plant tissue was increased up to 5.5 mg N l-1 and 2.5 mg N l-1 in the culture medium.