INVESTIGATION OF RELATIONS BETWEEN ABIOTIC VARIABLES, THEIR INFLUENCE ON THE PLANKTON PRIMARY PRODUCTIVITY AND THE MANURING EFFECT IN FISH PONDS

Le résumé fourni par la source

The experiment was carried out within three consecutive years (2004, 2005 and 2006). Seven earthen fish ponds (area varying from 1.8 to 3.9 dа) located in the Institute for Fishery and Aquaculture, Plovdiv, Bulgaria were included in the investigation. A manure dose of 3000 kg.ha–1 was used. The aim of this study was investigation of relations between the abiotic factors, their influence on the plankton primary productivity (PP) and the manuring effect in fish ponds. The bigger part of the abiotic factor variation was defined by the differences between the monthly sampling compared to the changes in the ponds within investigation period (2004/05/06). Concerning the abiotic factors there was a difference between first and last months. The great seasonal variability decreases the chance to find differences between the manured and the control ponds. The abiotic factors as the permanganate oxidability, oxygen content and рН value in the manured ponds had a higher level compared to control ponds during 2005. An increased level of the oxidability, phosphate phosphorus and рН value was found in the manured ponds during 2006.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.