Prethodno priopćenje
INFLUENCE OF TECHNOLOGICAL MEASURES ON CHANGES IN WATER CHEMISTRY OF CARP FISH PONDS
Krešimir Fašaić
; Ribarski centar, Zagreb
Ljubica Debeljak
; Agronomski fakultet, Sveučilište u Zagrebu, Zagreb
Biserka Stojić
; INA-Odjel za primjenu gnojiva, Kutina
Mirko Turk
; Ribarski centar, Zagreb
Sažetak
Investigations on the changes of water chemistry in conditions of variously treated fish ponds for culture of consumption fish with special emphasis on the incoming water was carried out on the fish farm »Draganići« in six experimental fish ponds: without fertilizer (variant I) and fertilized with mineral fertilizer NPK (12:12:12) of a total amount of 900 kg.ha-1 (variant II) together with supplement feeding the fish with grains, and without fertilizer with supplement feeding the fish with industrial brickets with 18% protein (variant III). The stock density of fish in all fish ponds was 3300 ind.ha-1.
During the culturing season from June to October, in all experimental fish ponds and in incoming water from the Stojnica brook, an expressed variation of individual chemical determinants were found, and the changes in the experimental ponds in comparison with the incoming water was established. The results are presented in Tables 2-5.
The minimum values 02 in variants II and III in comparison with the incoming water were less by 27%, while the maximum values were increased by 33%. This shows the expression of a fluctuation of these chemical variables in the experimental fish ponds.
The amount of NH4+ increased in all experimental fish ponds in relation to the incoming water, in variant I by 43%, in variant II by 93% and in variant III by 75%, on the average.
The amount of N03- increased in comparison to the incoming water by 10% (variant I), by 6% (variant II), and by 13% (variant III), on average, and the amount of P043- increased by 17% (variant I), by 207% (variant II) and by 28% (variant III). The maximum values of orthophosphate increased in variant II by 236%, while in variants I and III it was on the same level of the incoming water.
Ključne riječi
carp pond; water chemistry; fish nutrition; mineral fertilizer
Hrčak ID:
70515
URI
Datum izdavanja:
29.9.1994.
Posjeta: 956 *