Abstract

In order to contribute to the improvement of the productivity of rice-fish farming systems, the evaluation of growth performances and the survival rate of Oreochromis niloticus and Clarias gariepinus, through the use of local organic fertilizers in comparison with mineral fertilization have been carried out. The trial was conducted in the Western Highlands of Cameroon between May and October 2022. Thus, 3 treatments namely TB (cow dung at 1000 kg/h/week), TU (urea at 80 kg/ha) and a control (T0, i.e. non-fertilized), were repeated twice in a complete random design. Physico-chemical parameter readings were taken every months and periphyton samples collected at the end of the test. A sample of 30% of the total number of each species of fish was weighed and measured at the start and end of the test. Ultimately, fertilization with cow dung leads to a drop of oxygen levels (2.94 mg/l) as well as nitrogenous nutrient salts and an increase of water conductivity. Regarding periphytons, 6 genera divided into 3 families have been identified. The density was influenced (p<0.05) by the 2 fertilizers and was higher (p<0.05) with cow dung (35.105) than with urea (1.4*106) and the controller (2.21*106). Fertilization affected (p<0.05) the survival of C. gariepinus (84% with cow dung against 64% with urea), but not that of O. niloticus. The highest (p<0.05) growth performances were obtained whatever the species in the batches having received cow dung. Gains of 0.40 and 1.03 g/D with cow dung and 0.31 and 0.64 g/D with urea respectively for O. niloticus and C. gariepinus were obtained. Concerning the yields, the speculations (rice-fish), they were significantly higher with cow dung irrespective of the speculations. Also, and regardless of speculation, batch fertilized with cow dung had the significantly highest yields (fish and rice).