Theses and Dissertations


Title: The effect of no fertilization and non-nitrogenous fertilization upon the chemistry of water, the plankton, bottom organism and fish production in ponds that had received complete (N-P-K) fertilizers for the preceding 15-year period

Name: Rabanal, Herminio Ranit

Degree: PhD

Chair: Dr. Homer S. Swingle

Resides: FAA Library

University: Auburn

Location: Auburn, Alabama

Date: 1960

Pages: 109

Keywords: Fertilization,Non-Nitrogenous Fertilization,Water Chemistry,Plankton Production,Bottom Organism Production,Complete Fertilization.

Abstract:

Two species of fish, common carp and goldfish, were used to test the effect of no fertilization (0-0-0), non-nitrogenous fertilization (0-8-2), and complete fertilization (8-8-2, N-P2O5-K20) in ponds that had received continued application of complete fertilizers during the preceding 15-year period. Complete fertilization (8-8-2) resulted in an average production of 348.8 pounds of carp and 700.6 pounds of goldfish per acre. No fertilization (0-0-0) produced an average of 275.2 pounds of carp and 422.6 pounds of goldfish per acre, or 73.6 pounds less for carp and 278.0 pounds less for goldfish than complete fertilization. These differences were significant with goldfish but not with carp. Ponds with non-nitrogenous fertilization (0-8-2) produced an average of 312.4 pounds of carp and 616.2 pounds of goldfish per acre, or 36.4 pounds less for carp and 84.4 pounds less for goldfish than in the ponds with complete fertilization. Although the 8-8-2 had consistently higher average production than the 0-8-2 ponds, the differences did not reach a level of significance. The effects of complete fertilization during the preceding 15-year period in ponds that were unfertilized in the present experiment were estimated to have increased carp production 3.7 times and goldfish production 1.7 times that obtained in their original unfertilized state. The amounts of aquatic insects and plankton in the fertilized 8-8-2 and 0-8-2 ponds were significantly higher than in the unfertilized (0-0-0) ponds. The averages per sampling period of these organisms (insects and plankton) were consistently higher in the 8-8-2 than in the 0-8-2 ponds, but the differences were not statistically significant. The concentrations of total nitrogen dissolved and in suspension in the water were significantly different among treatments: highest in the completely fertilized ponds, next highest in the phosphate-potash fertilized ponds, and lowest in the unfertilized ponds. The total nitrogen content of the unfertilized pond waters remained at about the same level throughout the experimental period: that of the 0-8-2 ponds gradually increased: and that in the 8-8-2 ponds increased at an even higher rate. Organic nitrogen followed a trend parallel to that of the total nitrogen in the pond waters. Inorganic nitrogen (ammonia plus nitrate) gradually decreased during the experimental period. Ammonia which was more abundant than nitrate declined rapidly while nitrate increased slightly. Carp ponds had significantly lower levels of ammonia but higher levels of nitrate than goldfish ponds receiving similar treatments. The concentrations of dissolved inorganic phosphorus were significantly higher in the 8-8-2 and 0-8-2 ponds than in the 0-0-0 ponds. Phosphorus after its application disappeared from solution at the calculated rate of 12.7 and 14.3 per cent per day in the 0-8-2 and 8-8-2 ponds respectively. The biological data indicated that discontinuance of fertilization limited fish, aquatic insect, and plankton production. The chemical data tended to suggest that indigenous pond sources played the major role in supplying nitrogen in ponds previously fertilized for a 15-year period and used for fish cultural purposes: the magnitude of elemental nitrogen fixation was not measured.

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