Nitrogen Transformations in Ponds Receiving Polluted Water from Nonpoint Sources1
- G. B. Reddy and
- K. R. Reddy2
A laboratory study was conducted to determine the role of N transformations in ponds receiving inorganic N-rich effluents from septic fields, agricultural, and pasture watersheds. Undisturbed sediment columns were obtained from three ponds. Floodwater in the columns was enriched with either 15NH+4-N or 15NO−3-N. Ammonium removal rates ranged from 55 to 85 mg N m−2 d−1, while NO−3-N removal rates ranged from 48 to 71 mg N m−2 d−1. Twenty-three to 49% of floodwater 15NH+4-N diffused into the sediment during a 22-d incubation period and was recovered in 15NH+4-N (6–12% of the floodwater 15NH+4-N) and organic 15N fractions (14–37% of the floodwater 15NH+4-N). When 15NO−3-N was added to the floodwater, about 7% was tied up in the sediment. Ponds receiving effluents from septic tanks and pastured areas retained less floodwater N in the sediment compared to sediments of the pond receiving runoff from agricultural watershed.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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