Comparative evaluation of the fertilizer value of human urine, cow manure and their mix for the production of carp fingerlings in small holding tanks

Advanced fry of Indian carps and post-larvae of freshwater prawn were reared for 120?days in 18 small holding tanks using each treatment in triplicate as: (a) non-aerated and (b) aerated fresh human urine (0.01%), (c) cow manure (1.8?kg tank^?1), mixed treatment with cow manure and human urine under (d) iso-phosphorus and (e) iso-nitrogenous conditions and (f) control. Examination of water quality, primary productivity of phytoplankton, plankton and fish growth from different treatments revealed that the total fish yield was maximum in the cow manure treatment (621.5?g?tank^?1) followed by the mixed treatments under iso-nitrogenous (428?g?tank^?1) and iso-phosphorus (333?g?tank^?1) conditions. Fish yield in different treatments was the direct function of the gross and net primary productivity of phytoplankton which, in turn, were directly related to the concentrations of nitrate and phosphate levels of water as well as their ratios in different treatments employed.