Electronic Journal of Polish Agricultural Universities (EJPAU) founded by all Polish Agriculture Universities presents original papers and review articles relevant to all aspects of agricultural sciences. It is target for persons working both in science and industry,regulatory agencies or teaching in agricultural sector. Covered by IFIS Publishing (Food Science and Technology Abstracts), ELSEVIER Science - Food Science and Technology Program, CAS USA (Chemical Abstracts), CABI Publishing UK and ALPSP (Association of Learned and Professional Society Publisher - full membership). Presented in the Master List of Thomson ISI.

Copyright © Wydawnictwo Akademii Rolniczej we Wroclawiu, ISSN 1505-0297

Kolasa-Jamińska B. 2003. INFLUENCE OF THE DATE OF AUTUMN HARVESTING ON THE QUALITY OF DISCHARGED WATERS, EJPAU 6(2), #02.
Available Online: http://www.ejpau.media.pl/volume6/issue2/fisheries/abs-02.html

ABSTRACT

The rearing of carp K_2-3 in polyculture with a grass- carp, silver carp and European catfish was carried out within 1995- 1997, in six (1995-1996) or in seven (in 1997) variants of ponds differed in stocking densities as well as in kind of feed fed. The objective of the present paper was to verify if the change of harvest date from September into November can affect the quality of discharged waters. Estimation of discharged water quality was made on the basis of following chemical factors: dissolved oxygen, water pH, total suspended matter, chemical oxygen demand COD_Mn, ammonia nitrogen, nitrate nitrogen, nitrite nitrogen and phosphates. The change of harvest date for 40 days improved markedly the quality of discharged water. In November 1997 values of the hydrochemical parameters of water decreased twice on average, e.g. suspended matter from 600 to 200 mg dm ^–3, ammonium from 10.0 to 5.0 mg dm ^–3, while in November 1995 third or even five times

Key words: carp pond, hydrochemical parameters of water, water quality..

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