Effect of organic and chemical fertilization on growth performance, phytoplankton biomass and fish production in carp polyculture system

This study reports on the effect of organic (sheep and cow manure), and chemical fertilizers, on the phytoplankton, primary productivity and aquaculture production in the cultivation of carp in semi-intensive earthen ponds. The average biomass final (kg) were 1687.4, 1948.8 and 2370.6 kg / fed. in T1, T2 and T3, respectively. Treatment with chemical fertilizers was found to present the highest yield with 11.57 ± 0.67 kg/fed./day. It was followed by treatment with cow manure (9.20 ± 1.24 kg/fed./day) and sheep manure (7.79 ± 1.95 kg/fed./day). Concentrations of phytoplankton were significantly (p 0.05) higher in ponds fertilized with sheep and cow manures (1,824,726 and 1,416,416 cells/ml, respectively) than in ponds fertilized with chemical fertilizer (1,084,630 cells/ml). All of water quality parameters (P 0.05), were within the acceptable range during the present study. In general, conditions were adequate to obtain high yields without the commercial feed, therefore organic fertilizers application can be recommended, due to its availability and low costs.